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Trojan.MSIL.MALREP.THJOHAI

October 08, 2019
 ALIASES:

Trojan:MSIL/CryptInject!MTB (Microsoft); HEUR:Trojan.MSIL.Disfa.gen (Kaspersky)

 PLATFORM:

Windows

 OVERALL RISK RATING:
 DAMAGE POTENTIAL:
 DISTRIBUTION POTENTIAL:
 REPORTED INFECTION:

  • Threat Type: Trojan

  • Destructiveness: No

  • Encrypted:

  • In the wild: Yes

  OVERVIEW


This Trojan arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.

  TECHNICAL DETAILS

File Size:

699,904 bytes

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

08 Oct 2019

Arrival Details

This Trojan arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.

Installation

This Trojan drops the following copies of itself into the affected system:

  • %Application Data%\filename.exe

(Note: %Application Data% is the current user's Application Data folder, which is usually C:\Documents and Settings\{user name}\Application Data on Windows 2000(32-bit), XP, and Server 2003(32-bit), or C:\Users\{user name}\AppData\Roaming on Windows Vista, 7, 8, 8.1, 2008(64-bit), 2012(64-bit) and 10(64-bit).)

It adds the following processes:

  • "%Windows%\Microsoft.NET\Framework\v2.0.50727\vbc.exe"
  • %System%\lsass.exe
  • %Windows%\Microsoft.NET\Framework\v4.0.30319\mscorsvw.exe
  • %Windows%\Microsoft.NET\Framework64\v4.0.30319\mscorsvw.exe
  • %System%\svchost.exe -k LocalServiceAndNoImpersonation
  • %System%\sppsvc.exe
  • "%System Root%\Program Files\Windows Media Player\wmpnetwk.exe"
  • %System%\svchost.exe -k WerSvcGroup

(Note: %Windows% is the Windows folder, where it usually is C:\Windows on all Windows operating system versions.. %System% is the Windows system folder, where it usually is C:\Windows\System32 on all Windows operating system versions.. %System Root% is the Windows root folder, where it usually is C:\ on all Windows operating system versions.)

It creates the following folders:

  • %User Temp%\2fda
  • %Windows%\ServiceProfiles\NetworkService\AppData\Local\Microsoft

(Note: %User Temp% is the current user's Temp folder, which is usually C:\Documents and Settings\{user name}\Local Settings\Temp on Windows 2000(32-bit), XP, and Server 2003(32-bit), or C:\Users\{user name}\AppData\Local\Temp on Windows Vista, 7, 8, 8.1, 2008(64-bit), 2012(64-bit) and 10(64-bit).. %Windows% is the Windows folder, where it usually is C:\Windows on all Windows operating system versions.)

Other System Modifications

This Trojan deletes the following files:

  • %Application Data%\filename.exe:Zone.Identifier

(Note: %Application Data% is the current user's Application Data folder, which is usually C:\Documents and Settings\{user name}\Application Data on Windows 2000(32-bit), XP, and Server 2003(32-bit), or C:\Users\{user name}\AppData\Roaming on Windows Vista, 7, 8, 8.1, 2008(64-bit), 2012(64-bit) and 10(64-bit).)

Dropping Routine

This Trojan drops the following files:

  • %User Temp%\2fda\nss3.dll
  • %User Temp%\2fda\api-ms-win-crt-time-l1-1-0.dll
  • %User Temp%\2fda\api-ms-win-crt-runtime-l1-1-0.dll
  • %User Temp%\2fda\api-ms-win-core-rtlsupport-l1-1-0.dll
  • %User Temp%\2fda\api-ms-win-core-profile-l1-1-0.dll
  • %All Users Profile%\Microsoft\Windows\DRM\v3ks.sec
  • %User Temp%\2fda\api-ms-win-core-processenvironment-l1-1-0.dll
  • %User Temp%\2fda\api-ms-win-crt-conio-l1-1-0.dll
  • %User Temp%\12548660886267455292336.tmp-shm
  • %User Temp%\2fda\api-ms-win-crt-utility-l1-1-0.dll
  • %User Temp%\2fda\vcruntime140.dll
  • %User Temp%\2fda\api-ms-win-crt-convert-l1-1-0.dll
  • %User Temp%\2fda\nssdbm3.dll
  • %User Temp%\2fda\api-ms-win-core-util-l1-1-0.dll
  • %User Temp%\2fda\mozglue.dll
  • %User Temp%\2fda\api-ms-win-core-localization-l1-2-0.dll
  • %User Temp%\2fda\api-ms-win-core-timezone-l1-1-0.dll
  • %User Temp%\2fda\api-ms-win-core-processthreads-l1-1-0.dll
  • %User Temp%\2fda\api-ms-win-core-file-l1-2-0.dll
  • %User Temp%\2fda\api-ms-win-core-memory-l1-1-0.dll
  • %User Temp%\2fda\api-ms-win-crt-heap-l1-1-0.dll
  • %User Temp%\2fda\api-ms-win-crt-process-l1-1-0.dll
  • %User Temp%\2fda\api-ms-win-crt-private-l1-1-0.dll
  • %User Temp%\2fda\api-ms-win-core-interlocked-l1-1-0.dll
  • %User Temp%\2fda\api-ms-win-core-sysinfo-l1-1-0.dll
  • %User Temp%\2fda\api-ms-win-crt-stdio-l1-1-0.dll
  • %User Temp%\2fda\softokn3.dll
  • %User Temp%\2fda\api-ms-win-crt-math-l1-1-0.dll
  • %User Temp%\2fda\api-ms-win-core-synch-l1-2-0.dll
  • %User Temp%\2fda\api-ms-win-core-heap-l1-1-0.dll
  • %AppDataLocal%\Microsoft\Media Player\CurrentDatabase_372.wmdb
  • %User Temp%\2fda\api-ms-win-crt-filesystem-l1-1-0.dll
  • %User Temp%\2fda\api-ms-win-core-libraryloader-l1-1-0.dll
  • %User Temp%\2fda\api-ms-win-core-datetime-l1-1-0.dll
  • %User Temp%\2fda\api-ms-win-core-errorhandling-l1-1-0.dll
  • %User Temp%\2fda\ucrtbase.dll
  • %User Temp%\2fda\freebl3.dll
  • %User Temp%\2fda\api-ms-win-core-handle-l1-1-0.dll
  • %User Temp%\2fda\api-ms-win-core-processthreads-l1-1-1.dll
  • %User Temp%\12548660886267455292336.tmp-wal
  • %User Temp%\2fda\msvcp140.dll
  • %User Temp%\2fda\api-ms-win-core-file-l1-1-0.dll
  • %User Temp%\2fda\api-ms-win-crt-locale-l1-1-0.dll
  • %User Temp%\2fda\api-ms-win-core-namedpipe-l1-1-0.dll
  • %User Temp%\2fda\api-ms-win-core-synch-l1-1-0.dll
  • %User Temp%\2fda\api-ms-win-core-debug-l1-1-0.dll
  • %User Temp%\2fda\api-ms-win-core-string-l1-1-0.dll
  • %User Temp%\curbuf.dat
  • %All Users Profile%\Microsoft\Windows\DRM\drmstore.hds
  • %User Temp%\2fda\api-ms-win-crt-multibyte-l1-1-0.dll
  • %User Temp%\2fda\api-ms-win-core-console-l1-1-0.dll
  • %User Temp%\2fda\api-ms-win-crt-string-l1-1-0.dll
  • %User Temp%\2fda\api-ms-win-core-file-l2-1-0.dll
  • %User Temp%\2fda\api-ms-win-crt-environment-l1-1-0.dll

(Note: %User Temp% is the current user's Temp folder, which is usually C:\Documents and Settings\{user name}\Local Settings\Temp on Windows 2000(32-bit), XP, and Server 2003(32-bit), or C:\Users\{user name}\AppData\Local\Temp on Windows Vista, 7, 8, 8.1, 2008(64-bit), 2012(64-bit) and 10(64-bit).. %All Users Profile% is the common user's profile folder, which is usually C:\Documents and Settings\All Users on Windows 2000(32-bit), XP, and Server 2003(32-bit), or C:\ProgramData on Windows Vista, 7, 8, 8.1, 2008(64-bit), 2012(64-bit) and 10(64-bit). . %AppDataLocal% is the Local Application Data folder, which is usually C:\Documents and Settings\{user name}\Local Settings\Application Data on Windows 2000(32-bit), XP, and Server 2003(32-bit), or C:\Users\{user name}\AppData\Local on Windows Vista, 7, 8, 8.1, 2008(64-bit), 2012(64-bit) and 10(64-bit).)

Other Details

This Trojan connects to the following possibly malicious URL:

  • http://{BLOCKED}s.org

This report is generated via an automated analysis system.

  SOLUTION

Minimum Scan Engine:

9.850

Step 1

Before doing any scans, Windows 7, Windows 8, Windows 8.1, and Windows 10 users must disable System Restore to allow full scanning of their computers.

Step 2

Identify and terminate files detected as Trojan.MSIL.MALREP.THJOHAI

[ Learn More ]
  1. Windows Task Manager may not display all running processes. In this case, please use a third-party process viewer, preferably Process Explorer, to terminate the malware/grayware/spyware file. You may download the said tool here.
  2. If the detected file is displayed in either Windows Task Manager or Process Explorer but you cannot delete it, restart your computer in safe mode. To do this, refer to this link for the complete steps.
  3. If the detected file is not displayed in either Windows Task Manager or Process Explorer, continue doing the next steps.

Step 3

Search and delete these components

[ Learn More ]
There may be some components that are hidden. Please make sure you check the Search Hidden Files and Folders checkbox in the "More advanced options" option to include all hidden files and folders in the search result.
  • %User Temp%\2fda\nss3.dll
  • %User Temp%\2fda\api-ms-win-crt-time-l1-1-0.dll
  • %User Temp%\2fda\api-ms-win-crt-runtime-l1-1-0.dll
  • %User Temp%\2fda\api-ms-win-core-rtlsupport-l1-1-0.dll
  • %User Temp%\2fda\api-ms-win-core-profile-l1-1-0.dll
  • %All Users Profile%\Microsoft\Windows\DRM\v3ks.sec
  • %User Temp%\2fda\api-ms-win-core-processenvironment-l1-1-0.dll
  • %User Temp%\2fda\api-ms-win-crt-conio-l1-1-0.dll
  • %User Temp%\12548660886267455292336.tmp-shm
  • %User Temp%\2fda\api-ms-win-crt-utility-l1-1-0.dll
  • %User Temp%\2fda\vcruntime140.dll
  • %User Temp%\2fda\api-ms-win-crt-convert-l1-1-0.dll
  • %User Temp%\2fda\nssdbm3.dll
  • %User Temp%\2fda\api-ms-win-core-util-l1-1-0.dll
  • %User Temp%\2fda\mozglue.dll
  • %User Temp%\2fda\api-ms-win-core-localization-l1-2-0.dll
  • %User Temp%\2fda\api-ms-win-core-timezone-l1-1-0.dll
  • %User Temp%\2fda\api-ms-win-core-processthreads-l1-1-0.dll
  • %User Temp%\2fda\api-ms-win-core-file-l1-2-0.dll
  • %User Temp%\2fda\api-ms-win-core-memory-l1-1-0.dll
  • %User Temp%\2fda\api-ms-win-crt-heap-l1-1-0.dll
  • %User Temp%\2fda\api-ms-win-crt-process-l1-1-0.dll
  • %User Temp%\2fda\api-ms-win-crt-private-l1-1-0.dll
  • %User Temp%\2fda\api-ms-win-core-interlocked-l1-1-0.dll
  • %User Temp%\2fda\api-ms-win-core-sysinfo-l1-1-0.dll
  • %User Temp%\2fda\api-ms-win-crt-stdio-l1-1-0.dll
  • %User Temp%\2fda\softokn3.dll
  • %User Temp%\2fda\api-ms-win-crt-math-l1-1-0.dll
  • %User Temp%\2fda\api-ms-win-core-synch-l1-2-0.dll
  • %User Temp%\2fda\api-ms-win-core-heap-l1-1-0.dll
  • %AppDataLocal%\Microsoft\Media Player\CurrentDatabase_372.wmdb
  • %User Temp%\2fda\api-ms-win-crt-filesystem-l1-1-0.dll
  • %User Temp%\2fda\api-ms-win-core-libraryloader-l1-1-0.dll
  • %User Temp%\2fda\api-ms-win-core-datetime-l1-1-0.dll
  • %User Temp%\2fda\api-ms-win-core-errorhandling-l1-1-0.dll
  • %User Temp%\2fda\ucrtbase.dll
  • %User Temp%\2fda\freebl3.dll
  • %User Temp%\2fda\api-ms-win-core-handle-l1-1-0.dll
  • %User Temp%\2fda\api-ms-win-core-processthreads-l1-1-1.dll
  • %User Temp%\12548660886267455292336.tmp-wal
  • %User Temp%\2fda\msvcp140.dll
  • %User Temp%\2fda\api-ms-win-core-file-l1-1-0.dll
  • %User Temp%\2fda\api-ms-win-crt-locale-l1-1-0.dll
  • %User Temp%\2fda\api-ms-win-core-namedpipe-l1-1-0.dll
  • %User Temp%\2fda\api-ms-win-core-synch-l1-1-0.dll
  • %User Temp%\2fda\api-ms-win-core-debug-l1-1-0.dll
  • %User Temp%\2fda\api-ms-win-core-string-l1-1-0.dll
  • %User Temp%\curbuf.dat
  • %All Users Profile%\Microsoft\Windows\DRM\drmstore.hds
  • %User Temp%\2fda\api-ms-win-crt-multibyte-l1-1-0.dll
  • %User Temp%\2fda\api-ms-win-core-console-l1-1-0.dll
  • %User Temp%\2fda\api-ms-win-crt-string-l1-1-0.dll
  • %User Temp%\2fda\api-ms-win-core-file-l2-1-0.dll
  • %User Temp%\2fda\api-ms-win-crt-environment-l1-1-0.dll

Step 4

Search and delete these folders

[ Learn More ]
Please make sure you check the Search Hidden Files and Folders checkbox in the More advanced options option to include all hidden folders in the search result.
  • %User Temp%\2fda
  • %Windows%\ServiceProfiles\NetworkService\AppData\Local\Microsoft

Step 5

Scan your computer with your Trend Micro product to delete files detected as Trojan.MSIL.MALREP.THJOHAI. If the detected files have already been cleaned, deleted, or quarantined by your Trend Micro product, no further step is required. You may opt to simply delete the quarantined files. Please check the following Trend Micro Support pages for more information:

Step 6

Restore this file from backup only Microsoft-related files will be restored. If this malware/grayware also deleted files related to programs that are not from Microsoft, please reinstall those programs on you computer again.

  • %Application Data%\filename.exe:Zone.Identifier


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