More than 100 Victims Infected with DevilsTongue Spyware using Microsoft 0-day Vulnerabilities

Description

FortiGuard Labs is aware of a report that a commercially sold spyware "DevilsTongue" infected more than 100 victims by leveraging a couple of then 0-day Windows vulnerabilities which led Microsoft to release patches as part of Patch Tuesday July, 2021. The list of the victims includes politicians, human rights activists, journalists, academics, embassy workers, and political dissidents around the globe. The "DevilsTongue" spyware was developed by a private company that Microsoft labeled as "Sourgum" (a.k.a Candiru) and the company is believed to have sold its products to various government agencies.

How Serious of an Issue is This?

MEDIUM. While the "DevilsTongue" spyware infected more than 100 victims around the globe, the targets appear to have been carefully selected by the Sourgum clients, thus the attack is limited. Additionally, Microsoft has released patches for the 0-day vulnerabilities exploited by Sourgum.

How Widespread is this Attack?

According to Microsoft, "approximately half of the victims were found in Palestinian Authority, with most of the remaining victims located in Israel, Iran, Lebanon, Yemen, Spain (Catalonia), United Kingdom, Turkey, Armenia, and Singapore" and the targets are "politicians, human rights activists, journalists, academics, embassy workers, and political dissidents".

What Vulnerabilities were Exploited by DevilsTongue?

CVE-2021-31979 (Windows Kernel Elevation of Privilege Vulnerability) and CVE-2021-33771 (Windows Kernel Elevation of Privilege Vulnerability)

Are Patches Available for Reported Vulnerabilities Leveraged by DevilsTongue?

Yes, Microsoft released the patches for them as part of Patch Tuesday July, 2021.

Who was the Threat Actor that Carried out the Attack?

While DevilsTongue was developed and sold by Sourgram, the actual attacks were carried out by its clients that purchased the spyware.

Are there any Reports of Nation State Activity Associated with the Attack?

Yes. According to Microsoft and Citizen Lab, various government agencies used DevilsTongue to infect the victims. However there is no evidence that Sourgum is backed by any nation state. However there is no evidence that Sourgum, the developer of DevilsTongue, is backed by any nation state.

What do We Know about Sourgum (Candiru)?

Sourgum is a private company based in Israel and is specialized in developing and operating spyware for government agencies.

According to Citizen Lab, the company was initially founded as Candiru, their registration name has changed multiple times over the years.

What's the Goal of the Attacks?

From various reports, the goal of the attacks is to exfiltrate information from the victims.

Are there other Attacks that Sourgum was Linked to?

Citizen Lab believes Sourgum is linked to CHAINSHOT exploit kit that was used to deliver spyware as well as recent attacks reported by Google that leverage Chrome vulnerabilities. Again, Sourgum only develops and sells offensive tools but is not believed to carry out actual attacks.

What are the Chrome Vulnerabilities that were Exploited in the Attack that Sourgum may be Associated with?

CVE-2021-21166 (Chrome Object Lifecycle Issue in Audio) and CVE-2021-30551 (Chrome Type Confusion in V8).

Are the Patches Available for the Chrome Vulnerabilities?

Patch for CVE-2021-21166 and CVE-2021-30551 was released in March, 2021 and June, 2021 respectively.

What is the Status of Coverage?

FortiGuard Labs has IPS coverage in place for the vulnerabilities that were leveraged by DevilsTongue and other attacks referenced in this Threat Signal that are linked to Sourgum:

• MS.Windows.Kernel.CVE-2021-31979.Privilege.Elevation (definitions version 18.119)
• MS.Windows.Kernel.CVE-2021-33771.Privilege.Elevation (definitions version 18.119)
• Google.Chrome.V8.Property.Interceptor.Type.Confusion

All known network IOC's are blocked by the FortiGuard WebFiltering Client.

Are there any Indicators Available to Determine Whether my Computer is Infected with DevilsTongue?

Microsoft provided the following Indicator of Compromises in their blog post:

File locations

The hijack DLLs are in subfolders of \system32\ime\ with names starting with 'im'. However, they are blended with legitimate DLLs in those folders. To distinguish between the malicious and benign, the legitimate DLLs are signed (on Windows 10) whereas the DevilsTongue files aren't. Example paths:

• C:\Windows\System32\IME\IMEJP\imjpueact.dll
• C:\Windows\system32\ime\IMETC\IMTCPROT.DLL
• C:\Windows\system32\ime\SHARED\imecpmeid.dll

The DevilsTongue configuration files, which are AES-encrypted, are in subfolders of C:\Windows\system32\config\ and have a .dat extension. The exact paths are victim-specific, although some folder names are common across victims. As the files are AES-encrypted, any files whose size mod 16 is 0 can be considered as a possible malware config file. The config files are always in new folders, not the legitimate existing folders (e.g., on Windows 10, never in \Journal, \systemprofile, \TxR etc.). Example paths:

• C:\Windows\system32\config\spp\ServiceState\Recovery\pac.dat
• C:\Windows\system32\config\cy-GB\Setup\SKB\InputMethod\TupTask.dat
• C:\Windows\system32\config\config\startwus.dat

Commonly reused folder names in the config file paths:

• spp
• SKB
• curv
• networklist
• Licenses
• InputMethod
• Recovery

The .ini reg file has the unique name WimBootConfigurations.ini and is in a subfolder of system32\ime\. Example paths:

• C:\Windows\system32\ime\SHARED\WimBootConfigurations.ini
• C:\Windows\system32\ime\IMEJP\WimBootConfigurations.ini
• C:\Windows\system32\ime\IMETC\WimBootConfigurations.ini

The Physmem driver is dropped into system32:

• C:\Windows\system32\physmem.sys

Behaviors

The two COM keys that have been observed being hijacked for persistence are listed below with their default clean values. If their default value DLL is in the \system32\ime\ folder, the DLL is likely DevilsTongue.

• HKLM\SOFTWARE\Classes\CLSID\{CF4CC405-E2C5-4DDD-B3CE-5E7582D8C9FA}\InprocServer32 = %systemroot%\system32\wbem\wmiutils.dll (clean default value)
• HKLM\SOFTWARE\Classes\CLSID\{7C857801-7381-11CF-884D-00AA004B2E24}\InProcServer32 = %systemroot%\system32\wbem\wbemsvc.dll (clean default value)

Appendix

• Protecting customers from a private-sector offensive actor using 0-day exploits and DevilsTongue malware (Microsoft)
• Hooking Candiru Another Mercenary Spyware Vendor Comes into Focus (Citizen Lab)
• How we protect users from 0-day attacks (Google)
• CVE-2021-31979 (Windows Kernel Elevation of Privilege Vulnerability)
• CVE-2021-33771 (Windows Kernel Elevation of Privilege Vulnerability)
• CVE-2021-21166 (Chrome Object Lifecycle Issue in Audio)
• CVE-2021-30551 (Chrome Type Confusion in V8)