The REvil (also known as Sodinokibi) ransomware was first identified on April 17, 2019. It is used by the financially motivated GOLD SOUTHFIELD threat group, which distributes ransomware via exploit kits, scan-and-exploit techniques, RDP servers, and backdoored software installers. Secureworks® Counter Threat Unit™ (CTU) analysis suggests that REvil is likely associated with the GandCrab ransomware due to similar code and the emergence of REvil as GandCrab activity declined. CTU™ researchers attribute GandCrab to the GOLD GARDEN threat group


In one intrusion, the first second-stage custom loader (TEARDROP) was introduced to the environment by BusinessLayerHost.exe at around 10:00 AM UTC. 7z.dll), Far Manager (e.g. The Variant 2 custom loaders were mostly compiled from open-source source code of legitimate applications, such as 7-Zip and Far Manager (i.e. the open-source source code for these applications was modified to add in the malicious code). In some instances, certain development artifacts were left behind in the custom loader samples. For example, the following C++ header (.hpp) path was observed in a loader compiled from a modified Far Manager open-source source code (c:\build\workspace\cobalt_cryptor_far (dev071)\farmanager\far\platform.concurrency.hpp


KernelCallbackTable is initialized to an array of callback functions when user32.dll is loaded into memory, which are used whenever a graphical call (GDI) is made by the process. To hijack the control flow, malware replaces the USER32. _fnDWORD callback in the table with the malicious WMIsAvailableOffline function. Once the flow is hijacked and malicious code is executed the rest of the code takes care of restoring the KernelCallbackTable to its original state


In this case, repotaj.dll, which is ServHelper, will be extracted to %TEMP% and execute with the “feast” parameter as its export function. Once ServHelper is executed, it runs a PowerShell script to get information from the infected machine


The malware tries to delete the shadow copies two times, once before crypting the files in the infected system and secondly after crypting them


Apart from being a flexible and easy-to-use scripting language, BLADABINDI’s use of AutoIt is notable. It uses AutoIt (the FileInstall command) to compile the payload and the main script into a single executable, which can make the payload — the backdoor — difficult to detect


DEATHRANSOM creates an RSA-2048 public and private key pair. The shared secret is SHA256 hashed and used as the key to Salsa20 encrypt the RSA public and private keys. The RSA public key is used to encrypt the individual symmetric keys that are used to encrypt each file. A Base64 encoded version of the encrypted RSA keys and the victim’s Curve25519 public key is included in the ransom note, providing the threat actors the information needed to decrypt the victim's files. For the symmetric key, DEATHRANSOM calls RtlGenRandom to generate 32 random bytes. This is the 32 byte key used to AES encrypt each file. After the file is encrypted, the AES key is encrypted with the public RSA key and appended to the file. DEATHRANSOM lastly appends the four magic bytes of AB CD EF AB at the end of the encrypted file and uses this as a check to ensure that it does not encrypt an already encrypted file. The analyzed DEATHRANSOM sample used for comparison does not change the file extension


The final stage, however, is a dotnet application that takes several commands such as directory listing, screenshot, compress, upload, etc. It then creates random long string folder names in temp directories to host the collected files per category before compressing, encrypting and uploading to the C2 server


In an uninhibited Emotet infection, it’s likely the malware would have then attempted to move laterally to other machines in the environment. Malwarebytes has some good analyses of Emotet if you’re looking for further reading


Another interesting artefact is that the script modifies the modification, access and creation (MAC) times of the local log file to match the times of a legitimate file – desktop.ini in that example, as shown in Figure 13


infpub.dat appears to be capable of brute-forcing NTLM login credentials to Windows machines that have pseudo-random IP addresses


The code of this module is loaded directly into the exploited application and has several methods of payload execution. One of method uses a very interesting technique of payload execution which is designed mostly to bypass modern anti-malware products. This uses an interesting bug in the Windows DDE component. It is not a secret that anti-malware systems trigger on special system functions that are called in the context of potential vulnerable applications to make a deeper analysis of API calls such as CreateProcess, WinExec or ShellExecute


Although tracking threats like Winnti involves old-fashioned investigative work, Microsoft Threat Intelligence analysts take advantage of machine learning to work at scale. When attackers used Winnti to maintain access to web servers, they hid the implant in plain sight by masquerading it as a trusted, legitimate file


The attackers are using a tool with name plainpwd in order to dump Windows credentials from memory. This tool is a slightly modified version of the open-source project mimikatz


So attackers specify an external C&C server in the command line and the tool connects to this server using HTTP. This remote server is used as a proxy by attackers: the connection that goes to this server is redirected to the internal network by the tool and any response that the tool gets from a computer in the internal network goes to the C&C server. Thus, attackers can communicate with internal servers that are normally unreachable from the internet


IronNetInjector is made of an IronPython script that contains a .NET injector and one or more payloads. The payloads can be also .NET assemblies (x86/64) or native PEs (x86/64). When an IronPython script is run, the .NET injector gets loaded, which in turn injects the payload(s) into its own or a remote process


Prior to executing fully, Karagany uses a robust anti-VM detection function that can detect most commonly used virtualization platforms such as VMWare, VirtualBox, VPC, and generic virtualization techniques. Only the VMWare and VirtualBox checks retained, mainly based on loaded drivers and file paths. This change dramatically reduced the file size of the malware


Next, the dropper checks its own parent process for indications that it is running in a sandbox setup. It calculates the MD5 hash of the lower-case process image name and terminates if one of the following conditions are met


As with other versions of Winnti, the core component of the malware doesn’t natively provide the operators with distinct functionality⁸. This component is primarily designed to handle communications and the deployment of modules directly from the command-and-control servers. However, prior reporting⁹ suggests that the operators commonly deploy plugins for remote command execution, file exfiltration, and socks5 proxying on the infected host. We expect similar functionality to be leveraged via additional modules for Linux


In the third phase of the operation, the attackers harvested credentials stored on the compromised machines and performed lateral movement and infected new machines. The attackers also introduced a very rare and stealthy technique to communicate with their servers and exfiltrate data using Microsoft Outlook


The crypter mainly contains junk code to increase entropy of the sample and hide the actual code. We have found 2 crypter variants with some code differences, but mostly with the same logic applied


In this section, we describe how the various payloads are delivered based on what we have seen in our customer networks, as well as what we have established through open-source research. Unit 42 has yet to see any evidence of weaponized documents used to deliver BackConfig being attached on phishing emails and that phishing URL links in emails appear to be the Hangover group’s modus operandi


The updated module is called tvncDLL and allows the threat actor to monitor the victim and collect information that would enable pivoting to valuable systems on the network


The operators used the HyperBro Trojan as their last-stage in-memory remote administration tool (RAT). The timestamps for these modules are from December 2017 until January 2018. The anti-detection launcher and decompressor make extensive use of Metasploit’s shikata_ga_nai encoder as well as LZNT1 compression


For readers unaware of ngrok, this site is a simple reverse proxy used to let Internet-based users connect to servers located behind firewalls or on local machines that don't have a public IP address


At this stage the malware disables the Windows screen saver, then changes both the desktop wallpaper and the lock screen images to a custom image. These are the pair of identical JPEG and BMP images presenting the logo of Iran’s Railways and the message similar to the one displayed on the platform boards of different railway stations in Iran


Actors have downloaded POWERTRICK, Metasploit Meterpreter, and Cobalt Strike BEACON payloads following the initial compromise. BEACON payloads have commonly been executed after moving laterally to new hosts within the victim network. The attackers have employed Cobalt Strike payloads crafted to maintain persistence through reboot via a scheduled task on critical systems in victim environments. We have observed actors executing encoded PowerShell commands that ultimately executed instances of the PowerShell EMPIRE backdoor. In at least once case, attackers have maintained access to a victim environment using stolen credentials to access corporate VPN infrastructure configured to require only single-factor authentication


Initially the Cobalt group focused on jackpotting ATMs: they launched a program that sent commands directly to the dispenser to issue cash. Network penetration In all cases investigated by Group-IB, the Cobalt group used a set of spear phishing emails to gain initial access to the corporate infrastructure. However, some of the email addresses belong to employees that no longer work at the organization, which means that the Cobalt group likely uses out-of-date mailing lists. Each message contains an attachment that loads the payload – part of Cobalt Strike software – to the computer's operating memory. In order to make this download possible, attackers have tried several different formats of attachments and emails, as their primary task is to bypass mail filters, protection measures, and the company's security policy. 3 Example of a message with an executable attachment (.exe) The archive is password-protected in order to bypass anti-virus scans, security systems, and mail filters. However, when there is use of a security policy that prohibits the transfer of encrypted archives, such an email message may be blocked, so the attackers would send .doc files that contain exploits for Microsoft Office (fig. For organizations that perform timely updates of their systems and adhere to strict security policies, the Cobalt group employs another method to deliver malicious code through emails with Word documents containing a malicious macro. 6 Example of a message sent by attackers from a domain whose name is similar to the name of a real domain . As soon as the attachment is launched and the malicious code is executed, the Cobalt Strike payload is loaded in the memory. Provision of the malware survivability The Cobalt group uses different methods to ensure malware survivability on corporate networks


Both masscan and pnscan have been used before by TeamTNT actors. However, the addition of zgrab, a GoLang network scanner, marks the first time that a GoLang tool has been witnessed incorporated into TeamTNT’s TTPs. There was also an update to the masscan network scanner operation to include searching for TCP port 5555. This could indicate a new unknown target set for expanding TeamTNT cryptojacking operations. However, there is little evidence to support TeamTNT targeting Android devices


The attackers execute several Base64-encoded PowerShell commands in order to determine if the infected machine’s user is in the admin or domain admin group


The “pc” binary checks whether the infected system’s OS is Debian or RHEL/CentOS. Its routine, which involves dropping the cryptocurrency miner and other components, depends on OS. For Debian-based systems, it drops the cryptocurrency miner payload to /tmp/miner2. For CentOS/RHEL systems, it will download a tar (tape archive) file from the URL, hxxp://pm[.]ipfswallet[.]tk/cos7[.]tar[.]gz, containing the cryptocurrency miner and its multiple components, which is unpacked and then installed


The injected payload is known as Cobalt Strike Beacon and can be used to execute commands, inject other processes, elevate current processes or impersonate other processes, and upload and download files. The Get-NetComputer command from PowerView is renamed by the attackers to a random name


Once unpacked, the malware creates a copy of its own process with a suspended thread and injects the unpacked code into the new process before calling the ResumeThread API. Breaking on this function call in a debugger allows an analyst to dump the process and extract the unpacked Karagany binary for further analysis


After that, stage 2 payloads are still retrieved as Bitmap (BMP) images that use Least Significant Bit (LSB) Steganography to hide the real payloads. These images appear normal in image viewers


It also uses “ActiveXObject” utility to help in its execution through Microsoft products and internet browsers. The ActiveXObject object is used to create instances of OLE Automation objects in Internet Explorer on Windows operating systems. Several applications (Microsoft Office Word, Microsoft Office Excel, Windows Media Player, etc) provide OLE Automation objects to allow communication with them


h) It also uses “ActiveXObject” utility to help in its execution through Microsoft products and internet browsers. The ActiveXObject object is used to create instances of OLE Automation objects in Internet Explorer on Windows operating systems. Several applications (Microsoft Office Word, Microsoft Office Excel, Windows Media Player, etc) provide OLE Automation objects to allow communication with them


With the above done, the malware logs off all users and executes a small program — a “locker” — in a new thread. The path to the locker file named mssetup.exe is retrieved from the configuration. Finally, before moving to its main cause — wiping the system — the malware creates a scheduled task that assures its own persistence in the system. The scheduled task will be executed every time the system starts


Malware uses xor key [0x09, 0xff, 0x20] to decrypt content in .data section and get string “aHR0cDovLzUxLjE1LjE5Ni4zMC8xL2luZGV4LnBocA”. Then malware does base64 decoding to get the C2 address


Activation of these hooks is done by Ebury injecting its dynamic library into every descendant processes of sshd. To inject itself into subprocesses, Ebury hooks execve and use the dynamic linker LD_PRELOAD variable. Every time a new process is created, Ebury adds LD_PRELOAD=<Ebury_filename> to its environment. Once the new process is executed, Ebury’s dynamic library is loaded and its constructor is called, executing the hooking routines


One of the credential theft techniques identified by CrowdStrike was the use of a PowerShell script to execute Mimikatz in-memory. While in-memory Mimikatz is not particularly unique, the script executed by the threat actor was heavily obfuscated and encrypted the output using AES256. CrowdStrike was able to reconstruct the PowerShell script from the PowerShell Operational event log as the script’s execution was logged automatically due to the use of specific keywords. CrowdStrike recommends that organizations upgrade PowerShell on their systems, as this functionality is only available with PowerShell version 5 and above


Once the user enters the targeted website, the attacker is notified and can take over the device remotely. As the victim accesses their online banking account, the attacker can display full-screen overlay images (hence the name “remote overlay”) designed to appear like they are part of the bank’s website. These pages can either block the victim’s access to the site, allowing the attacker to move money after initial authentication, or include additional data fields that the user is prompted to fill out


Each of these weaponized documents used the same tactic for their attacks. Upon opening the document, it leveraged the ability of Microsoft Word to retrieve a remote template to then load a malicious macro document as seen in Figure 4


Daserf also uses file and folder names related to legitimate programs often found in Windows environments in order to blend in. Observed folder names include HP, Intel, Adobe, and perflogs and folders are generally created in either the root drive or the Application Data or Program Files folders. File names used in recent attacks include adobe.exe, adobe_sl.exe, intel.exe, and intellog.exe


Microsoft has been monitoring these attacks and notifying targeted customers for several months, but only recently reached a point in our investigation where we can attribute the activity to Strontium with high confidence. MSTIC’s investigation revealed that Strontium has evolved its tactics since the 2016 election to include new reconnaissance tools and new techniques to obfuscate their operations. In recent months, it has engaged in brute force attacks and password spray, two tactics that have likely allowed them to automate aspects of their operations. Strontium also disguised these credential harvesting attacks in new ways, running them through more than 1,000 constantly rotating IP addresses, many associated with the Tor anonymizing service. Strontium even evolved its infrastructure over time, adding and removing about 20 IPs per day to further mask its activity


Apart from targeting Gmail users, Pawn Storm has also abused OAuth in credential phishing attacks against high profile Yahoo users. Here is an example from 2015 where “McAfee Email Protection” is offered


Daserf — This backdoor has the functionality of a remote shell and can be used to execute commands, upload and download data, capture screenshots, and log keystrokes. As of this publication, BRONZE BUTLER demonstrates a preference for concurrently using Datper and xxmm in its operations. T-SMB Scan — This SMB scanning tool was originally published on a Chinese program-sharing website (pudn.com). BRONZE BUTLER removed its help message functionality. Use malware to upload the large list of enumerated files to the C2 server. Select specific files to steal, creating a new list. Use downloaders or other malware to send the new list to a compromised host. Use archiving software to collect files in a password-protected archive. Use an uploader or other malware to send the archived files to an attacker-controlled server. The uploader software is proprietary to this group, but Datper and xxmm also contain an uploading feature. Search proxy log files for evidence of web server scanning using the URL patterns associated with BRONZE BUTLER activity


an extra executable; - process hollowing shellcode; - a list of predefined executable names, which the malware uses as a future process name


ISMAgent prioritizes HTTP as its mechanism to communicate with the C2 server, but if it is unable to reach the C2 server it will switch to the DNS tunneling mechanism. To carry out its HTTP C2 communications, the Trojan prepends "www. to the configured C2 domain and issues a DNS query to resolve this domain


Last week, Unit 42 released a blog on a newly named threat group called DarkHydrus that we observed targeting government entities in the Middle East. The attack that we discussed in our previous publication involved spear-phishing to deliver a PowerShell payload we call RogueRobin; however, we are aware of DarkHydrus carrying out a credential harvesting attack in June 2018. It also appears that this an ongoing campaign, as we have evidence of previous credential harvesting attempts using the same infrastructure dating back to the Fall of 2017. The credential harvesting attacks used spear-phishing emails that contained malicious Microsoft Office documents that leveraged the “attachedTemplate” technique to load a template from a remote server. When attempting to load this remote template, Microsoft Office will display an authentication dialog box to ask the user to provide login credentials. When entered, these credentials are then sent to the C2 server, which allows DarkHydrus to collect the user account credentials. Based on Unit 42’s analysis, DarkHydrus used the open-source Phishery tool to create two of the known Word documents used in these credential harvesting attacks. As discussed in our previous blog, this further strengthens DarkHydrus’ use of the open source for their attack tools. A phishing attack to steal credentials like this is not new: US-CERT warned of the same technique by a different threat group in 2017. Based on this, we can reasonably presume this group will continue to carry out attacks against these kinds of targets in the Middle East in the near-future


The instance of Warzone we trapped has the ability to bypass UAC on the latest version of Windows 10. In this blog we’re going to talk about the XLS used as the attack vector and the UAC bypass technique used


Aside from security programs and other programs used daily that can be used to profile its targets, the DUBNIUM malware also checks for various program analysis tools including Pin and DynamoRIO. It also checks for a virtual machine environment. If some of these are detected, it quits its execution. Overall, the malware is very cautious and deterministic in running its main code


SMOKEDHAM communicates with its C2 server using HTTPS. The backdoor uses domain fronting to obfuscate its true C2 server. The fronted domain is configured by an earlier stage of execution and the actual domain is hard-coded in the backdoor. Mandiant observed the fronted domain lumiahelptipsmscdnqa.microsoft[.]com and hard-coded domain max-ghoster1.azureedge[.]net used for C2 server communication


The Leeson, Neoichor, and NumbIdea malware families typically use the Internet Explorer (IE) COM interface to connect and receive commands from hardcoded C2 servers


To deliver the malware to the victim machines, the Rocke group exploits vulnerabilities in Apache Struts 2, Oracle WebLogic, and Adobe ColdFusion. For example, by exploiting Oracle WebLogic vulnerability CVE-2017-10271 in Linux shown in Figure 1, a compromised Linux victim machine downloads backdoor 0720.bin and opens a shell


This version includes the stealer features mentioned in the previous version and additionally Remote Administration Tool features such as file uploading/download and arbitrary command execution. An interesting element is that the malware looks for filenames created with the previous version of KONNI. This implies that the malware targeted the same people as the previous version and they are designed to work together


In the period between January and March 2017 the TeleBots attackers compromised a software company in Ukraine (not related to M.E. Doc), and, using VPN tunnels from there, gained access to the internal networks of several financial institutions


The malware displays fake forms on top of the banking sites and intercepts credentials from the victims. It can also display a fake Windows Update whenever there is nefarious activity in the background, as seen in Figure 23


Zlh.exe is a legitimate, signed Norman Safeground AS application, which is used to sideload a malicious nflogger.dll DLL.The encrypted ZeroT payload is usually named NO.2.mui. The sideloaded DLL does not always use the same vulnerable executable, but it is always similar in functionality. Usually the DLL is not packed, but we have observed instances compressed by UPX. This malicious DLL is usually obfuscated with the same junk code: dummy API calls inserted in between real instructions (Fig. 7). The same obfuscation can be found in multiple functions in ZeroT itself


TA505 has also recently used LOLbins and legitimate Windows OS processes to perform malicious activities and deliver a payload without being detected. As the entry point of an attack, it delivers a sophisticated email containing a malicious Excel or Word file. The group notably abuses Excel 4.0 macro — a particularly old macro likely used to evade typical macro detection


During one investigation, APT32 was observed using a privilege escalation exploit (CVE-2016-7255) masquerading as a Windows hotfix. In another investigation, APT32 compromised the McAfee ePO infrastructure to distribute their malware as a software deployment task in which all systems pulled the payload from the ePO server using the proprietary SPIPE protocol. APT32 also used hidden or non-printing characters to help visually camouflage their malware on a system. For example, APT32 installed one backdoor as a persistent service with a legitimate service name that had a Unicode no-break space character appended to it. Another backdoor used an otherwise legitimate DLL filename padded with a non-printing OS command control code


The attackers also ran the nmap utility on the router VM and scanned ports on systems within the restricted segment of the enterprise network. On September 27, the attackers started removing all traces of their activity from the router, using the logrotate utility to set up automatic deletion of log files


PipeMon is a modular backdoor where each module is a single DLL exporting a function called IntelLoader and is loaded using a reflective loading technique. Each module exhibits different functionalities that are shown in Table 2


The next step after installing the malicious service would be to set up tunnels to access to the infected machine from remote hosts, for example using the following command


Turla, also known as Snake, is an infamous espionage group recognized for its complex malware. To confound detection, its operators recently started using PowerShell scripts that provide direct, in-memory loading and execution of malware executables and libraries. This allows them to bypass detection that can trigger when a malicious executable is dropped on disk


Four files tested in 2014 are based on the open-source project, cryptcat. Analysis of these cryptcat binaries indicates that the actor continually modified them to decrease AV detection rates. One of these files was deployed in a TEMP.Veles target’s network. The compiled version with the least detections was later re-tested in 2017 and deployed less than a week later during TEMP.Veles activities in the target environment. TEMP.Veles’ lateral movement activities used a publicly-available PowerShell-based tool, WMImplant. On multiple dates in 2017, TEMP.Veles struggled to execute this utility on multiple victim systems, potentially due to AV detection. Four files tested in 2014 are based on the open-source project, cryptcat. Analysis of these cryptcat binaries indicates that the actor continually modified them to decrease AV detection rates. One of these files was deployed in a TEMP.Veles target’s network. On multiple dates in 2017, TEMP.Veles struggled to execute this utility on multiple victim systems, potentially due to AV detection


The stage’s 0x102 resource is parsed and the files are dropped in either %ProgramFiles% or %AppData% in the randomly chosen folder. The creation times are changed to have the same values as kernel32.dll


Central Command network, including computers both in the headquarters and in the combat zones.The threat involved into this incident is referred as Agent.btz. There is even a clash with another threat that is also detected as Agent.btz by another vendor – but that's a totally different threat with different functionality. When loaded, its exported function DllEntryPoint() will be called automatically. Once a removable disk is connected to a computer infected with Agent.btz, the active malware will detect a newly recognized drive. It will drop its copy on it and it will create autorun.inf file with an instruction to run that file. Agent.btz file is not packed. Thus, it’s not known what kind of code could have been injected into the browser process. Agent.btz locates this resource by looking for a marker 0xAA45F6F9 in its memory map.File wmcache.nldThe second spawned thread will wait for 10 seconds. The collected network details are also saved into the log file.File winview.ocxThe second spawned thread will log threat activity into the file %system32%\winview.ocx.This file is also encrypted with the same XOR mask. Note: an attempt to run a valid thumb.db file, which is an OLE-type container has no effect.Files thumb.dd and mssysmgr.ocxAgent.btz is capable to create a binary file thumb.dd on a newly connected drive


The last retrieved module is a persistence module. If the victim appears valuable to the attackers, a GRIFFON implant installer is pushed to the victim’s workstation. This module stores another instance of the GRIFFON implant inside the registry to achieve persistence. Here is a PowerLinks-style method used by the attackers to achieve persistence and execute the GRIFFON implant at each user logon. The new GRIFFON implant is written to the hard drive before each execution, limiting the “file-less” aspect of this method


Another interesting discovery was a tool that was used during attacks to make queries to Active Directory using LDAP. This tool is able to dump detailed information about computers and usernames listed in Active Directory, and is tailored for a specific victim’s domain


The attackers then created scheduled tasks that would launch the ransomware with names based on variants of Windows Update Security or Windows Update Security Patches


Mouse position: Darkhotel repeatedly checks for the position of the mouse cursor on the screen. If the cursor remains at the center of the desktop, it is unlikely that a real user is using the system. Because of this, most sandboxes periodically move the mouse cursor or perform some other type of interaction with the desktop


In what appears to be a first on the cyber-espionage scene, a nation-state-backed hacking group has used a Google Chrome extension to infect victims and steal passwords and cookies from their browsers


The Python/TeleBot malware uses exactly the same approach; the Python backdoor code is obfuscated and packed into a standalone executable using PyInstaller. In addition, the Python code is ROT13 encoded, AES encrypted, compressed using zlib library and then Base64 encoded


But what really makes this backdoor interesting is the way in which it communicates with attackers in order to receive commands. Python/TeleBot abuses the Telegram Bot API from Telegram Messenger to communicate with the attackers. We have informed Telegram of this abuse of their communication platform


The shellcode loaded by the macro contains an encrypted DLL which is decrypted at runtime and then manually mapped into memory by the shellcode. After mapping the DLL, the shellcode jumps to the entry point of that DLL. The shellcode uses some kind of custom hashing method to resolve the APIs. We used hollows_hunter to dump the DLL and reconstruct the IAT once it is fully mapped into memory


It imports the specified Active Directory database NTDS.dit and registry file SYSTEM and exports the found password hashes into RecordedTV_pdump.txt and user details in RecordedTV_users.csv


The malware accomplishes this through querying the netsvc group value data located in the svchost group registry key which is HKLM\SOFTWARE\Microsoft\Windows NT\CurrentVersion\SvcHost


In most of the samples collected by the CTU research team, Sakula maintains persistence by setting the registry Run key (SOFTWARE\Microsoft\Windows\CurrentVersion\Run\) in either the HKLM or HKCU hive. Through 2013, registry persistence was set using standard Windows APIs. In the samples compiled in 2014, the adversary switched to adding the Run key by invoking cmd.exe


Delete the shadow volumes with vssadmin (“vssadmin Delete Shadows /all /quiet”). - Resize the shadow storage for all units starting from C to H units’ letters (hardcoded letters) to avoid the shadow volumes being made again. Using bcedit program to disable the recovery options in the boot of the machine and set to ignore any failure in the boot warning the user


The plugin is a Mimikatz version compiled in the Second_Release_PowerShell configuration. This version can be loaded into the address space of a PowerShell process via reflective DLL loading as implemented in the Exfiltration module of PowerSploit


It also has some basic anti-sandbox detection that tries to detect Virtual PC, Sandboxie, and VMware (example in Figure 6


When Xbash finds a destination has Hadoop, Redis or ActiveMQ running, it will also attempt to exploit the service for self-propagation. Three known vulnerabilities are targeted


RunningRat is a remote access Trojan (RAT) that operates with two DLLs. This DLL serves three main functions: killing antimalware, unpacking and executing the main RAT DLL, and obtaining persistence. The malware drops the Windows batch file dx.bat, which attempts to kill the task daumcleaner.exe; a Korean security program. The batch file then attempts to remove itself


A tool used by the adversary which wasn’t installed on the servers by default, was DSInternals. DSInternals is a PowerShell module that makes use of internal Active Directory features. The files and directories found on various systems of a victim match with DSInternals version 2.16.1. We have found traces that indicate DSInternals was executed and at which time, which match with the rest of the traces of the intrusion. We haven’t recovered traces of how the adversary used DSInternals, but considering the phase of the intrusion the adversary used the tool, it is likely they used it for either account discovery or privilege escalation, or both


From the attacks observed by Volexity, what is most notable is that Patchwork has pivoted its targeting and has launched attacks directly against US-based think tanks. Volexity has also found that, in addition to sending malware lures, the Patchwork threat actors are leveraging unique tracking links in their e-mails for the purpose of identifying which recipients opened their e-mail messages. This domain was not only used to send the phishing e-mails, but also to track which targets opened the e-mail. Within each of the HTML-formatted messages, an embedded image tag is used to beacon home to the attacker's domain, containing an unique identifier specific to the recipient. While the use of e-mail recipient tracking, a linked RTF document, and a final payload (QuasarRAT variant) remained the same, certain elements differed across campaigns observed. Exploitation and Malware Execution . Upon opening the above attachments, the recipient will be presented with a document that is a direct copy of a blog post or report released by the think tank organization being impersonated. Its called the "packager trick" because any file embedded in an RTF file using packager will be automatically dropped to the %tmp% folder (c:\Users\%username%\AppData\Local\Temp) when the RTF document is opened. Second, the threat actors exploit CVE-2017-8570 to achieve code execution via a malicious "scriptlet" file, or .sct file, which is also embedded in the malicious RTF document. The Patchwork threat actors also appear to have adopted a technique seen from other APT groups where they are now tracking the effectiveness of their campaigns by recording which recipients have opened the phishing message. Contact . Connect . This Website uses cookies, which are necessary to its functioning and required to achieve the purposes illustrated in our Cookie Policy


The malware launches another thread that scans for new drives attached to the system every three seconds. If a new drive is attached to the system and is not identified as a type CDROM drive, the malware begins the encryption process on the new drive. On new drives attached to the system, the malware may create the directory <Drive_letter>:\$RECYCLE and execute the following command


Shamoon enables the service RemoteRegistry, which allows a program to remotely modify the registry. It also disables remote user account control by enabling the registry key LocalAccountTokenFilterPolicy


SUNSPOT appends an entry in the log file with the date and time of the backdoor attempt and waits for the MsBuild.exe process to exit before restoring the original source code and deleting the temporary InventoryManager.bk file. If the Orion solution build is successful, it is backdoored with SUNBURST


TA505 uses fast flux, a DNS technique used to mask botnets by quickly shifting among compromised hosts, which allows cybercriminals to delay or evade detection. The domains the group has been using to distribute payloads were usually resolved across a lot of IPs


In at least one instance of EnvyScout delivery, we observed further enumeration of the executing browser’s environment, wherein the user-agent was used to determine whether a Windows machine received an ISO payload. If the visitor arrived via iOS, they were redirected to external infrastructure


Based on our technical analysis, telemetry, and data from submissions, we can assert with high confidence that this is the work of the Hidden Cobra group. These initial findings appear to be the first stage of Operation GhostSecret. For more on the global aspect of this threat, see “Global Malware Campaign Pilfers Data from Critical Infrastructure of Entertainment, Finance, Health Care, and Other Industries


Enumerate all CLRs loaded in the AD FS process Microsoft.IdentityServer.ServiceHost.exe - For each CLR, enumerate all running application domains and perform the following actions for each domain: Read the contents of the following encrypted FoggyWeb backdoor file into memory: C:\Windows\SystemResources\Windows.Data.TimeZones\pris\Windows.Data.TimeZones.zh-PH.pri Decrypt the encrypted FoggyWeb backdoor file using the Lightweight Encryption Algorithm (LEA). The LEA-128 key schedule uses the following hardcoded master key to generate the round keys: - Read the contents of the following encrypted FoggyWeb backdoor file into memory: C:\Windows\SystemResources\Windows.Data.TimeZones\pris\Windows.Data.TimeZones.zh-PH.pri - Decrypt the encrypted FoggyWeb backdoor file using the Lightweight Encryption Algorithm (LEA). The LEA-128 key schedule uses the following hardcoded master key to generate the round keys


Interestingly, the ChChes samples we observed were digitally signed using a certificate originally used by HackingTeam and later part of the data leaked when they were themselves hacked. Wapack labs also observed a similar sample targeting Japan in November. It’s not clear why the attackers chose to use this certificate, as it was old, had been leaked online, and had already been revoked by the time they used it. Digital certificates are typically used because they afford an air of legitimacy, which this one definitely does not


That persistence is achieved by adding a new task in the task scheduler – it deploys the malicious sample after every minute, to ensure that it keeps running


To further confuse anti-malware solutions, the loader contains the entire unobfuscated code of a legitimate open source application called Blink (https://github.com/crosire/blink), which never gets executed


The Calisto installation file is an unsigned DMG image under the guise of Intego’s security solution for Mac


The software installed on the compromised computer is of particular interest. Which programs are installed on the system. Which of them are executed automatically at each system start or user logon. Which programs are used by a particular user. If the attackers are interested, they are only one command away from these valuable data


The service-based DLL implant traverses to the /htdocs/ directory on the FTP server and looks for any files with the keywords


Finally, Grandoreiro detects two virtual environments – VMWare via its special I/O port and Virtual PC via the vpcext instruction


The attacker’s choice of IP addresses was also optimized to evade detection. The attacker primarily used only IP addresses originating from the same country as the victim, leveraging Virtual Private Servers


SUNSPOT is StellarParticle’s malware used to insert the SUNBURST backdoor into software builds of the SolarWinds Orion IT management product. SUNSPOT monitors running processes for those involved in compilation of the Orion product and replaces one of the source files to include the SUNBURST backdoor code. Several safeguards were added to SUNSPOT to avoid the Orion builds from failing, potentially alerting developers to the adversary’s presence


When the newer service variant of BitPaymer is run, it first determines if it is being executed from an alternate data stream. If it is not executed from an alternate data stream, the malware creates a file in the %APPDATA% folder with a random file name between three and eight characters long, containing uppercase and lowercase letters as well as numbers. It then copies itself to the alternate data stream :bin of the newly created file and creates a new process from the stream


Flame appears to have two modules designed for infecting USB sticks, called “Autorun Infector” and “Euphoria”. We haven’t seen them in action yet, maybe due to the fact that Flame appears to be disabled in the configuration data. Nevertheless, the ability to infect USB sticks exists in the code, and it’s using two methods


The modules are signed by an invalid digital certificates listed as “Tencent Technology (Shenzhen) Company Limited” with serial numbers, copied from real Tencent certificates


Capable of stealing documents sent to the printer queue. Steals written CD images. Capable of stealing files previously seen on removable drives once they are available again. Steals Internet Explorer, Netscape Navigator, FireFox and RealNetworks cookies. If deleted from Frontend file or related registry values, it will reappear after reboot with a new name and startup type


Recall that when the malicious code is executed, it invokes the extract_ei function on its own binary image, to check if the file is infected. If so, it opens itself, and reads the trailer to get the offset of where the file’s original bytes are located. It then writes these bytes out to a new file named: .<orginalfilename>1. This file is then set executable (via chmod) and executed (via execl


Next, the shellcode iterates through the PEB’s loader module list looking for the base address of Kernel32.dll. This is typical of shellcode, as the Kernel32.dll base address is necessary to resolve any dependency files required by the shellcode to run. With this address, the shellcode loads its dependency modules and resolves any necessary Windows Application Programming Interface (API) calls using standard shellcode API hashing. The following modules are loaded


Receive a file path from the C2 for a file to read. The target file is read and then split into smaller files named "<target_filename>.part_<part_number>" and stored on disk. This capability can be used to break large files of interest into smaller chunks to prepare them for exfiltration


This introduction of string obfuscation also suggests a development change aimed at evading detection. The header codes, filename references, and all of the operator commands were obfuscated and only decoded during execution of the KeyBoy DLL. Figure 6 shows a sampling of these strings, after decoding


The developer implemented a total of seven techniques to identify if the compromised system is a virtual machine. Additionally, the malware checks the SerialNumber and the version of the BIOS. The third technique uses the Win32_Computer entry in WMI. It checks if the manufacturer contains "VIRTUAL", "VMWARE" or "VirtualBox". The fourth technique checks the Processor ID of the system. The WMI request simply replies "not supported". This behaviour can be used to detect if the targeted system is a real machine. The last technique uses the MAC Address of the infected system. If the MAC Address starts by a well-known hexadecimal number, the system is identified as a virtual machine. The variant version of GX is used in the URI


COBALT DICKENS uses publicly available tools, including the SingleFile plugin available on GitHub and the free HTTrack Website Copier standalone application, to copy the login pages of targeted university resources. Metadata in a spoofed login page created on August 1 suggests that COBALT DICKENS sometimes uses older copied versions of target websites. A comment left in the source code indicates it was originally copied on May 1, 2017 (see Figure 3). However, the university was targeted by numerous COBALT DICKENS operations, including the August 2018 and August 2019 campaigns


NOBELIUM, with existing administrative permissions, was observed to drop a malicious loader named version.dll in the %WinDir%\ADFS\ folder where the AD FS service executable Microsoft.IdentityServer.ServiceHost.exe is located. Once the system or the AD FS service is restarted, Microsoft.IdentityServer.ServiceHost.exe loads mscoree.dll, which in turn loads mscoreei.dll. As mentioned above, mscoreei.dll has a delay load import named version.dll


In recent BitPaymer IR engagements, Falcon Intelligence linked the initial infection vector to fake updates for a FlashPlayer plugin and the Chrome web browser. These fake updates are served via legitimate websites that have been compromised, and use social engineering to trick users into downloading and running a malicious executable. These fake update campaigns appear to be a pay-per-install service that is simply used by INDRIK SPIDER to deliver its malware, as other malware has also been delivered via the same campaigns


One of the reconnaissance commands was to run a modified nbtscan tool ("NetBIOS nameserver scanner") to identify available NetBIOS name servers locally or over the network. Nbtscan has been used by APT10 in Operation Cloud Hopper to search for services of interest across the IT estate and footprint endpoints of interest. It is also capable of identifying system information


The attacker used a temporary file replacement technique to remotely execute utilities: they replaced a legitimate utility with theirs, executed their payload, and then restored the legitimate original file. They similarly manipulated scheduled tasks by updating an existing legitimate task to execute their tools and then returning the scheduled task to its original configuration. They routinely removed their tools, including removing backdoors once legitimate remote access was achieved


Modifying the Standard Information timestamps (created, modified, accessed) of every downloaded executable to match a randomly selected file from the System32 directory that was created prior to 2013


1) Suckfly's first step was to identify a user to target so the attackers could attempt their initial breach into the e-commerce company's internal network. 2) On April 22, 2015, Suckfly exploited a vulnerability on the targeted employee's operating system (Windows) that allowed the attackers to bypass the User Account Control and install the Nidiran back door to provide access for their attack. 3) After the attackers successfully exploited the employee’s system, they gained access to the e-commerce company's internal network. To do this the attackers used a signed credential-dumping tool to obtain the victim's account credentials. With the account credentials, the attackers were able to access the victim's account and navigate the internal corporate network as though they were the employee. 4) On April 27, the attackers scanned the corporate internal network for hosts with ports 8080, 5900, and 40 open. Ports 8080 and 5900 are common ports used with legitimate protocols, but can be abused by attackers when they are not secured. Based on Suckfly scanning for common ports, it’s clear that the group was looking to expand its foothold on the e-commerce company's internal network. 5) The attackers’ final step was to exfiltrate data off the victim’s network and onto Suckfly’s infrastructure. While we know that the attackers used the Nidiran back door to steal information about the compromised organization, we do not know if Suckfly was successful in stealing other information


After these strings are decrypted, the malware will load a series of Microsoft Windows API calls to be used later on. After these functions are loaded, Comnie determines if it is running within the %TEMP% directory of the victim machine. In the event it is not running within this directory, it will copy itself to %TEMP% and execute this newly created file with an argument of the original file’s path. A total of 64MB of garbage data is appended to this copied file, likely as a way to deter any security products in place that may be scanning files on disk. After running within the %TEMP% path, Comnie will delete the original file. After Comnie has been copied to the %TEMP% directory, it will look for the presence of the ‘DQuit.tmp’ file in this path. It is unclear how this file is used exactly, as it does not appear to ever be written during runtime by Comnie. Comnie continue to enter its installation routine. In doing so, it will attempt to detect the following Anti-Virus products via various techniques


This list of strings differs from previously analyzed SofacyCarberp samples, such as the variant discussed in our June 2016 blog “New Sofacy Attacks Against US Government Agency“ that chose from a list of strings .xml, .pdf, .htm or .zip. After establishing that the system has Internet access, the Trojan will gather detailed system information and send it to the C2 server


In April, security researchers in the Microsoft Threat Intelligence Center discovered infrastructure of a known adversary communicating to several external devices. Further research uncovered attempts by the actor to compromise popular IoT devices (a VOIP phone, an office printer, and a video decoder) across multiple customer locations. The investigation uncovered that an actor had used these devices to gain initial access to corporate networks. In two of the cases, the passwords for the devices were deployed without changing the default manufacturer’s passwords and in the third instance the latest security update had not been applied to the device


When exploiting the intended targets, the threat actors used malicious .docx files to capture user credentials. The documents retrieved a file through a “file://” connection over SMB using Transmission Control Protocol (TCP) ports 445 or 139. When a user attempted to authenticate to the domain, the C2 server was provided with the hash of the password. Local users received a graphical user interface (GUI) prompt to enter a username and password, and the C2 received this information over TCP ports 445 or 139. Note: a file transfer is not necessary for a loss of credential information. Symantec’s report associates this behavior to the Dragonfly threat actors in this campaign. 1](link is external


Otherwise, the malware bypasses UAC and escalates privileges with two different approaches – one for Windows 10 and the other for older versions


The logging functions are hooked so that whenever the backdoor is used, nothing gets sent to the logging facility, leaving no trace of the backdoor in the log files on disk. If the backdoor is not in use, logging will behave normally and function calls will get redirected to the original function implementation


The second part of API hooking hooks on “GetExtendedTcpTable. GetExtendedTcpTable” is used for retrieving a table that contains a list of TCP endpoints available to the application, and it is frequently used in some network-related commands, such as netstat. The purpose of the hook is to remove TCP endpoint records of certain PIDs. The second function, “GetRTTAndHopCount,” acts as the place to put the injected hooking code


The output of the downloaded batch file is saved to “%PUBLIC%\Libraries\tp\<batch filename>.txt”. The script will then upload the output of this batch file by including the data in a sequence of DNS queries. The exfiltrates the output of the batch script by splitting up the data within the text file into chunks up to 23 bytes and sends the data within a series of DNS queries that have the following structure


Installs UnionCryptoTrader in folder /Applications/UnionCryptoTrader.app/Contents/MacOS/ - Installs .unioncryptoupdater in folder /Applications/UnionCryptoTrader.app/Contents/Resources/ Note: the leading “.” makes it unlisted in the Finder app or default Terminal directory listing - Note: the leading “.” makes it unlisted in the Finder app or default Terminal directory listing - Executes a postinstall script Moves .vip.unioncrypto.plist to folder LaunchDaemons Changes the file permissions on the plist to Root Runs unioncryptoupdater Moves .unioncryptoupdater to folder /Library/UnionCrypto/unioncryptoupdater Makes .unioncryptoupdater executable - Moves .vip.unioncrypto.plist to folder LaunchDaemons - Changes the file permissions on the plist to Root - Runs unioncryptoupdater - Moves .unioncryptoupdater to folder /Library/UnionCrypto/unioncryptoupdater - Makes .unioncryptoupdater executable


It uses GetlogicalDrives to get a bitmask of all the drives available on the system, then iterates over each possible drive letter


Ryuk does not encrypt files from within its own process memory space, but injects into a remote process. Before injecting into a remote process, Ryuk attempts to adjust its token privileges to have the SeDebugPrivilege. Before injecting into a remote process, Ryuk also calls CreateToolhelp32Snapshot to enumerate all running processes. If a process is found that is not named csrss.exe, explorer.exe, lsaas.exe, or is running under NT AUTHORITY system account, Ryuk will inject itself into this single process. By ensuring that the process is not running under NT AUTHORITY, the developers are assuming the process is not running under another account and therefore can be written to. Ryuk uses a combination of VirtualAlloc, WriteProcessMemory and CreateRemoteThread to inject itself into the remote process


Next, the third-stage DLL will load the "Waqybg" resource into memory. As the resource is stored in reverse byte order, the third-stage DLL will restore it by reversing the bytes and then proceed to decompress it. The decompressed data is the fourth stage wiper payload. After decompressing the data, the third-stage DLL copies a legitimate Windows utility "InstallUtil.exe" into the %TEMP% directory, creates a suspended process with it and injects the fourth-stage wiper into the process. Finally, it resumes the process and transfers the execution flow to the fourth-stage wiper. Creates InstallUtil.exe process


Whitefly has consistently used a technique known as search order hijacking to run Vcrodat. This technique takes advantage of the fact that Windows does not require an application to provide a specific path for a DLL that it wishes to load. If no path is provided, Windows searches for the DLL in specific locations on the computer in a pre-defined order. Attackers can therefore give a malicious DLL the same name as a legitimate DLL but place it ahead of the legitimate version in the search order so that it will be loaded when Windows searches for it. Whitefly frequently delivers Vcrodat as a malicious DLL that has the same name as DLLs belonging to legitimate software from various security vendors. The group leverages search order hijacking to assure that its malicious DLLs will be executed. Targeting security applications could allow the attackers to gain higher privileges for the malware, since the vendor’s component may be run with elevated privileges


The malware’s next action is to check if the execute privilege is SYSTEM. When the execute privilege is SYSTEM, the malware will get the process “Explorer.exe”, get the token of the user that launched the process and impersonate it. It is a downgrade from SYSTEM to another user with less privileges to avoid affecting the desktop of the SYSTEM user later


The threat actors commonly created web shells on the intended targets’ publicly accessible email and web servers. The threat actors used three different filenames (“global.aspx, autodiscover.aspx and index.aspx) for two different webshells


Currently LockerGoga does not support any worm-like capabilities that would allow it to self-propagate by infecting additional hosts on a target network. We have observed LockerGoga moving around a network via the server message block (SMB) protocol, which indicates the actors simply manually copy files from computer to computer


Finally, command line tried to execute (iex is an alias for Invoke-Expression) the code downloaded from the IP address 104[.]168[.]237[.]21. Threat actors abused sslip.io for connection to C&C - a service that provides free IP to domain mapping to make SSL certificate generation easier for traffic encryption. While this service is legitimate and widely used, the malware abused it in an attempt at evading detection when connecting to C&C servers


If the payload determines it is not running in a sandbox, it will attempt to install itself to the system to persistently execute


With the file written to the system, the Trojan calls the "GetishideAbById" SOAP action to determine whether or not the C2 server wishes to execute the newly dropped file in a hidden window. This request is followed by a call to "GetisrunasAbById" to determine if the Trojan should use "runas" to execute the downloaded executable with elevated privileges, which would display the UAC dialog for the user to click


Numbered Panda has a long list of high-profile victims and is known by a number of names including: DYNCALC, IXESHE, JOY RAT, APT-12, etc. Numbered Panda has targeted a variety of victims including but not limited to media outlets, high-tech companies, and multiple governments. Numbered Panda has targeted organizations in time-sensitive operations such as the Fukushima Reactor Incident of 2011, likely filling intelligence gaps in the ground cleanup/mitigation operations. One of the most interesting techniques that Numbered Panda likes to use is to dynamically calculate the Command and Control (C2) port by resolving a DNS. The malware will typically use two DNS names for communication: one is used for command and control; the other is used with an algorithm to calculate the port to communicate to. There are several variations of the algorithm used to calculate the C2 port, but one of the most common is to multiply the first two octets of the IP address and add the third octet to that value. This is typically represented as: (A * B) + C – common values might be 200.2.43.X, which would result in communication on port 443. Numbered Panda will frequently use blogs or WordPress in the c2 infrastructure, which helps to make the network traffic look more legitimate. CrowdStrike has observed Numbered Panda targeting high-tech, defense contractors, media organizations, and western governments


Appending a file signature header to all encrypted data, prior to upload or download, by randomly selecting from the file types


Figure 5 shows the splash image displayed by the Enigma protector prior to executing the malicious payload, which is a wallpaper image available at wallpaperswide.com. The splash screen feature acts as a sandbox evasion technique, as it requires user interaction in the form of clicking the screen before the malicious code runs


Conti uses a multithreading technique to fast encrypt all the files. This routine takes seconds to just a few minutes depending on the number of files on the machine. Each sample has a unique extension that the malware adds to the encrypted files. While using Cybereason with prevention mode off to allow investigation of the ransomware execution, it is possible to see the encryption activity and the creation of new files


Besides of fetching a list of scanning targets, Xbash will also request C2 server via URI “/p” to fetch a list of weak passwords for brute forcing


Some versions of the Orz backdoor have 32- and 64-bit embedded DLLs, stored internally as base64 strings. Their purpose is to simply run another binary. These are used as loaders for future executable payloads, using the well-known process hollowing technique. To use the MockDll, the backdoor creates a configuration .ini file like that shown in Figure 14


The shellcode loader was observed on one infected device as updater.exe with the Metasploit-style service name APTYnDS1ABEuUHEA, indicating that it was installed as a service


From one of the hosts, we discovered that the actor executed a credential harvesting tool named Responder and moved laterally using Windows commands. Lazarus overcame network segmentation, exfiltrating data from a completely isolated network segment cut off from the internet by compromising a router virtual machine, as we explain below under “Overcoming network segmentation


1) If the malware was executed with the "install" command-line argument, which uses .NET Framwork’s InstallHelper method to install the malware as a service. 3) If no arguments are provided and the malware determines it is running in a Windows environment, it saves a DLL to the system that it injects into the explorer.exe process. The injected DLL executable loads the malware’s executable and runs it within memory of the explorer.exe process


This static set of characteristics, combined with the minimal use of obfuscation in their phishing attacks, may benefit organizations that are potential targets for IRON TILDEN.ToolsTaegis™ XDR Adversary Software Coverage Tool


Browser credential stealing: Capability to steal credentials (username and password) from the installed browsers, Microsoft Internet Explorer (MSIE), and Google Chrome browser. Figures 7 and 8 show the code sections responsible for stealing the credentials from MSIE and Chrome browser respectively


The malware then grants itself debugging privileges by modifying its security token to add SeDebugPrivilege. This step is a prerequisite for the remainder of SUNSPOT’s execution, which involves reading other processes’ memory


Interestingly, there is an option in the RC2CL module to turn off its backdoor functionality and act as a proxy. In this case, the malware turns off the Windows firewall and creates a server that relays communication between a client and C&C server, or between two clients


The legitimate application is a digitally signed sample of Kaspersky Anti-Virus (AV) 6.0 for Windows Workstations. When the Kaspersky application is run, it loads a file named msi.dll, which is located within the same directory. The XOR-decode process, which skips zeroes, uses the single-byte key 0x88


In this attack, spear phishing was used as the initial infection vector. Before launching the attack, the group studied publicly available information about the targeted organization and identified email addresses belonging to various departments of the company


In order to avoid raising suspicions from the victim, CSPY Downloader exploits a known UAC bypass technique that uses the SilentCleanup task to execute the binary with elevated privileges


If the ransomware is not executed with administrator rights or if the infected host runs Windows Vista or later, it will attempt to elevate its privileges. In short, WastedLocker uses a well-documented UAC bypass method [1] [2]. It chooses a random file (EXE/DLL) from the Windows system32 folder and copies it to the %APPDATA% location under a different hidden filename. Next, it creates an alternate data stream (ADS) into the file named bin and copies the ransomware into it. WastedLocker then copies winsat.exe and winmm.dll into a newly created folder located in the Windows temporary folder


A service that ensures Carbon’s persistency is created. Its name can either be “srservice”, “ipvpn” or “hkmsvc” depending of the operating system version running on the compromised machine


After having registered the Print Processor, PipeMon restarts the print spooler service (spoolsv.exe). As a result, the malicious print process is loaded when the spooler service starts. Note that the Print Spooler service starts at each PC startup, which ensures persistence across system resets


After patching, the threat actor can use the Skeleton Key password configured at the time of deployment to log in as any domain user. Legitimate users can still log in using their own passwords


Create a Safe Array and copy the decrypted FoggyWeb backdoor bytes to the array. It then calls the Load() function for the current application domain to load the FoggyWeb DLL into the application domain. After the FoggyWeb DLL is loaded into the current application domain, the loader invokes the following method from the DLL: Microsoft.IdentityServer.WebExtension.WebHost. Create a Safe Array and copy the decrypted FoggyWeb backdoor bytes to the array. It then calls the Load() function for the current application domain to load the FoggyWeb DLL into the application domain. After the FoggyWeb DLL is loaded into the current application domain, the loader invokes the following method from the DLL: Microsoft.IdentityServer.WebExtension.WebHost


In the first path, obtaining the SAML signing certificate normally entails first querying the private encryption key that resides on the AD FS container and then using that key to decrypt the signing certificate. The certificate can then be used to create illicit but valid SAML tokens that allow the actor to impersonate users, enabling them to access enterprise cloud applications and services


The websites contain numerous articles and content to make them seem legitimate; in some cases the websites have over 10,000 individual news articles. Volexity has found the content is largely scraped and reposted in full from various other legitimate online news outlets. This appears to be done in an automated fashion and most likely through WordPress plugins. Numerous posted articles and images can be directly tracked back to other online blogs and newspapers; sometimes the byline or even watermark in images show directly where the article was sourced. In some cases, only a small number of pages on the site contains malicious code; in other cases, the profiling code is pervasive


Checking for specific keyboards and languages is a known evasion tactic meant to avoid running on analysis systems not configured, as the actor’s targeted victim would be configured


MSTIC has observed NICKEL drop their malware into existing installed software paths. They did this to make their malware appear to be files used for an installed application. The following are example paths


If the bot is running with a regular user privilege, persistence is established using the registry “Run” method. The loader DLL component is written to “%APPDATA%\mswinload[.]dll” and a “mswinload” value is added to the “Run” key to execute ordinal #1 of the DLL with rundll32[.]exe


In order to deploy an implant for the final payload, ScarCruft uses a multi-stage binary infection scheme. As a rule, the initial dropper is created by the infection procedure. One of the most notable functions of the initial dropper is to bypass Windows UAC (User Account Control) in order to execute the next payload with higher privileges. Afterwards, the installer malware creates a downloader and a configuration file from its resource and executes it. The downloader malware uses the configuration file and connects to the C2 server to fetch the next payload. In order to evade network level detection, the downloader uses steganography. The downloaded payload is an image file, but it contains an appended malicious payload to be decrypted


Bisonal main module The DLL (pvcu.dll) is Bisonal malware but using a different cipher for C2 communication that other publicly documented samples. Booz Allen Hamilton in 2014 and AhnLab in 2015 reported on Bisonal using a simple XOR cipher to hide the C2 address strings in the body. The Bisonal sample we observed in this case employs the RC4 cipher with the key “78563412”. To date, all Bisonal samples we have seen using RC4 use this same key. The oldest sample we have dates to 2014, so this variant has been in the wild for several years. Adding to the change in encryption type, a large part of the code such as network communication procedures, and the persistence method have been re-written. For example, the Bisonal malware in 2012 used send() and recv() APIs to communicate with its C2


At the end of the encryption process, Pay2Key will also terminate the MS SQL service using the following command net stop mssqlserver > nul in order to release the files locked by the service


As a previous write-up on H1N1 by Arbort Networks describes, the LINK command in this instance results in H1N1 downloading and executing a file from a remotely hosted URL using WinINet HTTP requests. The loader also has the functionality of downloading and executing a base64 encoded file contained in the response from the command and control server via the FILE command


PLEAD also uses CVE-2017-7269, a buffer overflow vulnerability Microsoft Internet Information Services (IIS) 6.0 to compromise the victim’s server. This is another way for them to establish a new C&C or HTTP server


The Trojan does not encrypt the data sent via DNS beacons, rather it converts the ASCII characters into their hexadecimal values and includes these values in cleartext. The DNS beacons sent from the Helminth executable have the following structure, which is very similar to the script version


In addition, the threat actors created a scheduled task named reset, which was designed to automatically log out of their newly created account every eight hours


Wrote indicators based on observed attacker activity • Identified lateral movement, unique backdoors, credential theft, data theft, recon, persistence creation, etc


The Conti Ransomware uses AES-256 encryption via a hard-coded public key. The unique factor is the use of multiple threads for the encryption process, which allows faster encryption as compared to other ransomwares. The ransomware uses a CreateIoCompletionPort() call to create 32 thread instances which work simultaneously to encrypt files. After encryption, the ransomware adds extension to all the encrypted files. It can be seen in the image below


Over a few days' span, the threat actors install remote access tools on additional systems based upon the results of the network reconnaissance. They use At.exe to schedule tasks to run self-extracting RAR archives, which install either HttpBrowser or PlugX. CTU researchers observed the threat actors collecting Cisco VPN profiles to use when accessing the victim's network via VPN (see Figure 13


The organizational backup server was among the first targeted. When Ryuk was detected and stopped on the backup server, the attackers used the icacls command to modify access control, giving them full control of all the system folders on the server


This thread searches for for files with the following extensions on fixed drives and sends them to C2 every 60 minutes


The delivery document uses the XLSX extension typically used by OpenXML documents, but the file itself is actually an OLE (XLS) document. The file extension to file type discrepancy was caused by the actor using Excel's built-in encryption capability, which stores XLSX ciphertext and the information needed for decryption in an OLE document


We identified new MSIL components deployed by Zebrocy. While recent Zebrocy versioning was 7.1, some of the related Zebrocy modules that drop file-stealing MSIL modules we call Covfacy were v7.0. For example, one sent out to a handful of countries identifies network drives when they are added to target systems, and then RC4-like-encrypts and writes certain file metadata and contents to a local path for later exfiltration. The stealer searches for files 60mb and less with these extensions


Earlier versions of UPPERCUT used the hard-coded string “this is the encrypt key” for Blowfish encryption when communicating with a C2. However, in the latest version, the keys are hard-coded uniquely for each C2 address and use the C2’s calculated MD5 hash to determine which key to use, as shown in Figure 10


With this approach, the luring message shown in the Figure 2 now serves another purpose. Not only does it lure the victim into enabling the macros, but it also is assigned an alternate text: “fkwarning”, as seen in Figure 5. The macro has code to check this attribute to make sure the luring message shape object is present. If this object is not found, the macro will exit without downloading additional payloads


That new instance of RegAsm.exe is then responsible for handling the brunt of the malicious activity (data harvesting, exfiltration). We can also see frequent use of ‘Process Hollowing’ as an injection method. Process Hollowing allows for the creation or manipulation of processes through which sections of memory are unmapped (hollowed) with that space then being reallocated with the desired malicious code


To deploy the file injector, the instrumentor downloads additional payloads to be injected into a benign process


The program copies itself as <Hangul full path>HncReporter.exe and changes the default program association in the registry to open HWP documents. To do so, it alters following registry values


Another tool written in Go, GoldFinder was most likely used as a custom HTTP tracer tool that logs the route or hops that a packet takes to reach a hardcoded C2 server. When launched, the malware issues an HTTP request for a hardcoded IP address (e.g. hxxps://185[.]225[.]69[.]69/) and logs the HTTP response to a plaintext log file (e.g. loglog.txt created in the present working directory). GoldFinder uses the following hardcoded labels to store the request and response information in the log file


Another interesting technique this malware uses is Visual Studio’s Resource Manager. This is a feature built into Visual Studio that allows one to attach basically any file to the original binary and get a pointer to its data with a few simple API calls. Siloscape uses this method to write the Tor archive to the disk, as well as the unzip binary used to open the archive. It also uses Tor to securely connect to its C2


The source code of SUNBURST was likely sanitized before being included in SUNSPOT. The use of generic variable names, pre-obfuscated strings, and the lack of developer comments or disabled code is similar to what could be obtained after decompiling a backdoored Orion binary, as illustrated in Figure 2, which provides a comparison between the injected source code (top) and a decompilation output (bottom


Ebury sequentially tries the generated domain names until it finds one that has a TXT record set by the operator. To verify the ownership of the domain, Ebury checks whether the TXT record can be decrypted using an RSA public key embedded in its code


The first backdoor that the TeleBots group relied heavily on was Python/TeleBot.A, which was rewritten from Python in the Rust programming language. The functionality remains the same: it is a standard backdoor that uses the Telegram Bot API in order to receive commands from, and send responses to, the malware operator


After the extensive validation described above, the backdoor enters its main execution stage. At its core, the backdoor is a very standard one that receives instructions from the C2 server, executes those instructions, and sends back information. The type of commands that can be executed range from manipulating of registry keys, to creating processes, and deleting files, etc. effectively providing the attackers with full access to the device, especially since it’s executing from a trusted, signed binary


Get.exe appears to be a custom tool used to scan IP-ranges for HTTP service information. NCC Group and Fox-IT decompiled the tool for analysis. This showed the tool was written in the Python scripting language and packed into a Windows executable file. Though Fox-IT didn’t find any direct occurrences of the tool on the internet, the decompiled code showed strong similarities with the source code of a tool named GetHttpsInfo. GetHttpsInfo scans the internal network for HTTP & HTTPS services. The reconnaissance tool getHttpsInfo is able to discover HTTP servers within the range of a network


In July 2018, Unit 42 analyzed a targeted attack using a novel file type against at least one government agency in the Middle East. It was carried out by a previously unpublished threat group we track as DarkHydrus. Based on our telemetry, we were able to uncover additional artifacts leading us to believe this adversary group has been in operation with their current playbook since early 2016. Once opened, Excel will retrieve whatever object is at the URL inside the file. These files have most recently been found in use by criminals to deliver commodity RATs such as Flawed Ammyy. In DarkHydrus's case, the preferred payload retrieved in their previous attacks were exclusively open-source legitimate tools which they abuse for malicious purposes, such as Meterpreter and Cobalt Strike. However, in this instance, it appears that this group used a custom PowerShell based payload that we call RogueRobin


Some payloads leveraged DLL side loading, a technique that involves running a legitimate, typically digitally signed, program that loads a malicious DLL. The DLL acts as a stub loader, which loads and executes shell code. BRONZE UNION previously used this technique to enable execution of PlugX and HttpBrowser tools in a way that is challenging for network defenders to detect


To execute the main downloaded payload, the loader tries to masquerade as a legitimate Windows service, claiming in its fake description, that it is used to support packed applications


Prior to downloading secondary payloads, CSPY Downloader initiates an extensive series of checks to determine if it is being debugged or running in a virtual environment, by searching for specific virtualization-related loaded modules, the process PEB structure, various file paths, registry keys, and memory


When executed, the malware first establishes a SOCKS5 connection to 192.157.198.103 using TCP port 1913. The malware sends the SOCKS5 connection request "05 01 00" and verifies the server response starts with "05 00". The malware then requests a connection to 192.184.60.229 on TCP port 81 using the command "05 01 00 01 c0 b8 3c e5 00 51" and verifies that the first two bytes from the server are "05 00" (c0 b8 3c e5 is the IP address and 00 51 is the port in network byte order


PIONEER KITTEN’s namesake operational characteristic is its reliance on SSH tunneling, through open-source tools such as Ngrok and the adversary’s custom tool SSHMinion, for communication with implants and hands-on-keyboard activity via Remote Desktop Protocol (RDP


This is likely to make it appear as if nothing is amiss to the user (as high CPU usage is a red flag of cryptocurrency-mining malware


The VBShower backdoor has the same philosophy of the validator version of PowerShower. Its aim is to complicate forensic analysis by trying to delete all the files contained in “%APPDATA%\..\Local\Temporary Internet Files\Content.Word” and “%APPDATA%\..\Local Settings\Temporary Internet Files\Content.Word


The VBScript in turn runs rundll32.exe, activating the Cobalt Strike DLL (step #5) using a clean parent/child process tree completely disconnected from the SolarWinds process. Finally, the VBScript removes the previously created IFEO value to clean up any traces of execution (step #6) and also deletes the following registry keys related to HTTP proxy


The threat actor also attempted to use OWA account credentials likely acquired during an earlier phase of the intrusion. BRONZE UNION appeared to leverage other compromised infrastructure, presumably to make reentry attempts seem legitimate. This attempt illustrates the importance of thorough planning when conducting an eviction and the need for continuous vigilance for evidence of reentry


Next, the loader checks that it’s not running in a virtualized environment (VMWare or Hyper-V) or under a debugger. For the hardware virtualization check, the loader obtains the hardware device list and checks if the MD5 of the vendor ID is equal to a predefined list


If the bot is running as admin on Windows XP or 7, persistence is established using application shimming [1]. It uses a method very similar to the one described by FireEye in their blog post “To SDB, Or Not To SDB: FIN7 Leveraging Shim Databases for Persistence” [3]. A shim database (SDB) is created (Figure 13) to patch services[.]exe with the loader code and then installed with sdbinst[.]exe


To suppress the User Access Control (UAC) prompt that normally occurs during privilege elevation, the malware uses a UAC bypass technique first documented in August 2016. This bypass requires temporarily setting either the registry key HKCU\Software\Classes\ms-settings\shell\open\command on Windows 10, or the registry key HKCU\Software\Classes\mscfile\shell\open\command on Windows 7 to execute the malware. Once the registry key is set, the malware launches the Windows event viewer process eventvwr.msc, which will inadvertently launch the malware set in the registry keys with elevated privileges


Malicious actors commonly maintain persistence on a victim’s system by installing the malware-as-a-service. Volgmer queries the system and randomly selects a service in which to install a copy of itself. The malware then overwrites the ServiceDLL entry in the selected service's registry entry. In some cases, HIDDEN COBRA actors give the created service a pseudo-random name that may be composed of various hardcoded words


The first stage shellcode contains an interesting NOP sled with alternative instructions, which was most likely designed in such a way to avoid detection by antivirus products looking for large NOP blocks inside flash files


The C2 server address is not embedded directly inside Tomiris: instead, it connects to a signalization server that provides the URL and port to which the backdoor should connect. Then Tomiris sends GET requests to that URL until the C2 server responds with a JSON object of the following structure


First, it captures the desktop window and sets the background color to black. It then writes "All your files are encrypted. For more information see “README-FOR-DECRYPT.txt" with DrawText API to a bitmap image and saves it as "encr.bmp" in the public pictures folder. Finally, it changes the desktop wallpaper to the new image using the SystemParametersInfoAPI with the SPI_SETDESKWALLPAPER flag


FIN7 has consistently utilized legally purchased code signing certificates to sign their CARBANAK payloads. Finally, FIN7 has leveraged several new techniques that we have not observed in other CARBANAK related activity


This code invokes time twice, with a sleep in between …then compares if the differences between the two calls to time match the amount of time that was system slept for. To detect sandboxes that patch (speedup) calls to sleep


At the beginning of October 2021, Proofpoint researchers identified public samples of Gamaredon RTF template injection documents which impersonated the Ukrainian Ministry of Defense. This tactic is consistent with reporting on this APT group that links Gamaredon to the Russian FSB operating in the Republic of Crimea and the city of Sevastopol. The files communicate with the domain pretence77.glorious[.]nonima[.]ru which also was a remote template delivery URL used by several Microsoft Office Word documents that impersonated Ukrainian government organizations. These Office files communicate with actor infrastructure using a URI pattern previously observed among Gamaredon malicious Microsoft Office phishing documents. Specifically, the Microsoft Office documents used remote template injection to retrieve malicious payload files using URIs with the directory “/ELENAPC/principles/” on several occasions. Additionally, in several instances the resources retrieved delivered an MP3 file as a delivery resource


The main C2 loop starts after the initial upload of the reconnaissance data, iterating once every approximately 30 seconds. For the first five minutes, each iteration will capture a screenshot of the display and upload it to the "normal" subdirectory with an encoded timestamp as the filename. After the first five minutes, the screenshot uploads once every five minutes


Since the FoggyWeb loader version.dll is an unmanaged application, it cannot directly access the virtual runtime environment that the managed AD FS code is executed within. The loader overcomes this limitation and loads the backdoor alongside the AD FS code by leveraging the CLR hosting interfaces and APIs to access the virtual runtime environment within which the AD FS code is executed


The instrumentor script also performs a cleanup of the cookies for Google Chrome and Microsoft Edge browsers. This activity is performed after the implants are in place to force users to reauthenticate. This is done by simply terminating any browser processes running on the system and then deleting the cookie files on disk


If the bot is running with admin privileges on a Windows version newer than Windows 7, persistence is established using the registry “image file execution options” method


Daserf — This backdoor has the functionality of a remote shell and can be used to execute commands, upload and download data, capture screenshots, and log keystrokes. It uses RC4 encryption and custom Base64 encoding to obfuscate HTTP traffic. Datper uses an RC4-encrypted configuration to obfuscate HTTP traffic. xxmm (also known as Minzen) — This RAT and likely successor to Daserf AES-encrypts HTTP communications using a one-time encryption key. As of this publication, BRONZE BUTLER demonstrates a preference for concurrently using Datper and xxmm in its operations. Source: Secureworks) - RarStar — This custom tool uploads RAR archives to a specified URL as POST data (see Figure 6). RarStar encodes the POST data using Base64 and a custom XOR algorithm. RarStar HTTP POST request. T-SMB Scan — This SMB scanning tool was originally published on a Chinese program-sharing website (pudn.com). BRONZE BUTLER removed its help message functionality. When exfiltration is complete, the uploader (or Datper or xxmm) immediately uses the del command to delete the RAR archives. Search proxy log files for evidence of web server scanning using the URL patterns associated with BRONZE BUTLER activity


An analysis of these files found that they all leveraged a remote template injection technique that allows the documents to pull down the malicious code once they are opened. This allows the attacker to have control over what content is sent back to the victim in an otherwise benign document. Recent examples of the remote template “dot” file URLs these documents use include the following


These anti-forensic recovery commands are quite interesting and appear to make use of an undocumented feature of the vssadmin resize command. While the first command in Figure 2 above, vssadmin Delete Shadows /all /quiet, is commonly used by ransomware, the command option vssadmin resize shadowstorage is rarely used. In situations where shadow copies were not created by vssadmin, but by third-party applications (such as backup software), vssadmin can display an error and not delete the backups. Try removing them with the backup application which created them. The vssadmin resize shadowstorage command is a “hack” that relies on vssadmin to delete storage when the shadow copies are resized. It forces the shadow copies to be deleted regardless of their context. The command works by resizing the default shadow volume size from 10 percent to 401 MB (the minimum size is 300 MB). Then the shadow storage is set to unbounded, which allows it to use all available disk space. The shadow copies are then deleted by calling the command vssadmin Delete Shadows /all /quiet a second time


After initialization, SUNSPOT monitors running processes for instances of MsBuild.exe, which is part of Microsoft Visual Studio development tools. Copies of MsBuild.exe are identified by hashing the name of each running process and comparing it to the corresponding value, 0x53D525. The hashing algorithm used for the comparison is ElfHash and is provided in Python in Figure 1


The “WmiApCom.bat” file is simply used to start “WmiApCom”, which happens to be the exact same file as the one dropped by the malicious Word documents. However, this is most likely meant to be a mechanism to update the compromised host with a new version of the LOWBALL malware


Although it has only recently been launched, IcedID already uses redirection attacks. The redirection scheme IcedID uses is not a simple handover to another website with a different URL. Rather, it is designed to appear as seamless as possible to the victim. These tactics include displaying the legitimate bank’s URL in the address bar and the bank’s correct SSL certificate, which is made possible by keeping a live connection with the actual bank’s site


TG-3390 uses DLL side loading, a technique that involves running a legitimate, typically digitally signed, program that loads a malicious DLL. CTU researchers have observed the threat actors employing legitimate Kaspersky antivirus variants in analyzed samples. The DLL acts as a stub loader, which loads and executes the shell code. The adversaries have used this technique to allow PlugX and HttpBrowser to persist on a system


messengers. Figures 9 and 10 show FakeM attempting to resemble MSN or Yahoo. Messenger traffic, as the first 32-bytes contain data that resemble legitimate traffic generated by these chat programs


At execution, it installs an application-defined Windows hook. The hook gets windows messages indicating when a network drive has been attached. Upon adding a network drive, the hook calls its “RecordToFile” file stealer method


The first way in which the malware can be launched is by hijacking a DLL. Being placed in the same folder as explorer.exe, the wrapper DLL is loaded during the Windows startup into the Windows Explorer process instead of the legitimate library located in the %windir%\system32 folder


proxy-servers, web-servers, or software update servers. After that, these intermediary servers are used by ProjectSauron as internal proxy nodes for silent and inconspicuous data exfiltration, blending in with high volumes of legitimate traffic


As mentioned in the Hermes to Ryuk section, Ryuk uses a combination of symmetric (AES) and asymmetric (RSA) encryption to encrypt files. Without the private key provided by WIZARD SPIDER, the files cannot be decrypted and are unrecoverable. A thread is created for the encryption of each file and each file is encrypted with its own AES key. After the file has been encrypted, a file extension of .RYK is appended to the file. All directories will have a ransom note of (RyukReadMe.txt) written to the directory


The original variant of FakeM generates network beacons to its C2 server that begin with a 32-byte header that in most cases is meant to blend into network traffic generated by legitimate applications. Following this 32-byte header, the original variant of FakeM includes data encrypted using a custom encryption cipher that uses an XOR key of “YHCRA” and bit rotation between each XOR operation


Carbanak campaigns can also use legitimate programs and remote access software for command and control. They also employ standard non-application layer protocols for communication.


After this, the Carbanak backdoor can then be used to log keystrokes and capture screenshots, steal and delete cookies, inject malicious code on sites, and monitor various traffic. For lateral movement, the malware abuses remote and system administration tools.


For FIN7 attack routines, data can be compressed and/or encrypted before being exfiltrated.


FIN7 gathers information on network shares.


The other infection chain involves an attached .XLS file containing an Excel formula that utilizes a PowerShell command (Figure 2) to access paste.ee, a Pastebin alternative, that accesses a second encrypted PowerShell command (Figure 3).


In Carbanak attacks, the groups’ attacks can involve logging into services that accept remote connections and using stolen password hashes through the “pass the hash” method


On the other hand, FIN7 takes advantage of Mshta, a utility that can execute VBScript, and scheduled tasks to run malicious code on user systems.


In both Carbanak and FIN7 attacks, communication with users’ compromised systems is done through bypassing firewalls or network detection systems via commonly used ports, using connection proxies to avoid direct connections to the threat group’s infrastructure, employing the command-and-control channel to remotely copy files from an external system, blending in with existing network traffic by using standard application layer protocol, and taking advantage of standard cryptographic protocol to disguise command-and-control traffic.


Panda Stealer is deployed through spam emails posing as business quote requests to lure unwary victims into opening malicious Excel files. We have identified two infection chains: in one, an .XLSM attachment contains macros that download a loader (Figure 1). Then, the loader downloads and executes the main stealer.


FIN7 attacks can and inject code into processes and hijack the search order used to load DLL files.


Decoding these PowerShell scripts revealed that they are used to access paste.ee URLs for easy implementation of fileless payloads. The CallByName export function in Visual Basic is used to call the load of a .NET assembly within memory from a paste.ee URL.


Carbanak also collects information on accounts, files and directories, group permissions, and registries.


FIN7 utilizes guardrails to restrict execution and abused utilities that allow indirect command execution that can go past security restrictions


After moving through the network and identifying assets to target, the next step would be to gather key data. At the collection phase, Carbanak and FIN7 campaigns harvest data from local system sources and through input and screen capture (as performed in a related campaign using the Tirion malware).


They also add programs to a startup folder that can be referenced with a registry run key. We detected a variant of the Carbanak malware that adds registry entries and keys as an autostart technique. Credentials of existing valid accounts were also abused.


Cobalt Strike was also used to continuously communicate with the main command-and-control (C&C) server.


This example of BazarLoader generated command and control (C2) activity, retrieving BazarBackdoor using HTTPS traffic from 104.248.174[.]225 over TCP port 443.


Use the latest attack patterns, Kubernetes (K8s) or Docker API targeting, which were featured in two reports focusing on TeamTNT operations, Black-T: New Cryptojacking Variant from TeamTNT and Hildegard: New TeamTNT Cryptojacking Malware Targeting Kubernetes.


The attacker then executed a persistent malicious PowerShell code that was used to download and execute another PowerShell backdoor file in the server from the malicious IP address 185[.]82[.]219[.]201, as shown in Figure 7.


The PowerShell command executed after the Microsoft Exchange exploitation is responsible for downloading and executing another PowerShell script from the command-and-control (C&C) server 185[.]82[.]219[.]201


This PowerShell backdoor was observed to be related to the SystemBC malware as a service. The script has a hard coded C&C server IP address and port number to connect to, with data passed to the “Rc4_crypt” function before connection.


In our case study, approximately two minutes after Cobalt Strike activity started, a tool to enumerate an AD environment appeared on the infected host at C:\ProgramData\AdFind.exe.


Our analysis shows that the Crimson RAT malware is compiled as a .NET binary with minimal obfuscation. This could indicate that the cybercriminal group behind this campaign is possibly not well-funded.


Earth Karkaddan actors are known to use the Crimson RAT malware in its campaigns to communicate with its command-and-control (C&C) server to download other malware or exfiltrate data.


After downloading and executing these files, one of the child processes created other files and the executable setup.exe/setup-installv1.3.exe, which was extracted from 320yea_Teamviewer_15206.zip via WinRAR.exe. This file seems to be the source of most of the downloaded malicious files, as seen in the following figure.


The BazarLoader DLL was immediately copied to another location and made persistent through the Windows registry


These infections provide backdoor access that criminals use to determine whether the host is part of an Active Directory (AD) environment. If so, criminals deploy Cobalt Strike and perform reconnaissance to map the network


The malicious Excel spreadsheet was discovered on Wednesday, Aug. 18, 2021, and it has a last modified date of Tuesday, Aug. 17. The filename had an .xlsb file extension. This file has macros designed to infect a vulnerable Windows host with BazarLoader. Figure 2 shows a screenshot of the Excel file.


Once the executable file is executed, it will proceed to unzip a file named mdkhm.zip and then execute a Crimson RAT executable named dlrarhsiva.exe.


BazarLoader is Windows-based malware spread through various methods involving email


The loaded module is a simple dropper. Upon loading the module, the AutoOpen method will be invoked. The malicious code in this method drops the final payload executable into %AppData%\service.exe and executes it (see Figure 6)


The spreadsheet’s macro code retrieved a malicious Dynamic Link Library (DLL) file for BazarLoader from the following URL


this Excel template was created by a threat actor trying to instill confidence by taking advantage of the DocuSign brand name and image.


Crimson RAT can steal credentials from browsers, collect antivirus information, capture screenshots, and list victim drives, processes, and directories. We have observed how an infected host communicates with a Crimson RAT C&C server to send exfiltrated information including PC name, operating system (OS) information, and the location of the Crimson RAT malware inside the system.


Cobalt Strike leads to reconnaissance of an infected host’s environment. In our lab environments, this reconnaissance activity can start within a few minutes after Cobalt Strike traffic first appears.