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TROJ_MERETAM.E

August 30, 2018
 Analysis by: Arvin Roi Macaraeg
 ALIASES:

Trojan:Win32/MereTam.A (Microsoft), Trojan.Win32.Crypt.aeoo (Kaspersky), Trojan-FPRW!D9E10DD7DA74 (McAfee)

 PLATFORM:

Windows

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

  • 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:

577,536 bytes

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

08 Aug 2018

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%\msdesk\{Malware 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, XP, and Server 2003, or C:\Users\{user name}\AppData\Roaming on Windows Vista, 7, and 8.)

It adds the following processes:

  • cmd.exe /c sc stop WinDefend
  • cmd.exe /c powershell Set-MpPreference -DisableRealtimeMonitoring $true

Other System Modifications

This Trojan deletes the following files:

  • %System%\Tasks\Microsoft\Windows Defender\MP Scheduled Scan

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

Dropping Routine

This Trojan drops the following files:

  • %Application Data%\msdesk\FAQ
  • %Application Data%\msdesk\README.md
  • %Application Data%\msdesk\Modules\systeminfo32
  • %Application Data%\msdesk\Modules\injectDll32
  • %Application Data%\msdesk\Modules\injectDll32_configs\dinj
  • %Application Data%\msdesk\Modules\injectDll32_configs\sinj
  • %Application Data%\msdesk\info.dat
  • %Application Data%\msdesk\Modules\networkDll32
  • %Application Data%\msdesk\Modules\networkDll32_config\dpost
  • %Application Data%\Microsoft\Windows\Recent\CustomDestinations\d93f411851d7c929.customDestinations-ms
  • %System%\Tasks\MsSysToken
  • %Application Data%\msdesk\Modules\injectDll32_configs\dpost

(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, XP, and Server 2003, or C:\Users\{user name}\AppData\Roaming on Windows Vista, 7, and 8.. %System% is the Windows system folder, where it usually is C:\Windows\System32 on all Windows operating system versions.)

Other Details

This Trojan connects to the following possibly malicious URL:

  • http://{BLOCKED}o.net/plain
  • {BLOCKED}.{BLOCKED}.40.98
  • {BLOCKED}.{BLOCKED}.119.186
  • {BLOCKED}.{BLOCKED}.210.130
  • {BLOCKED}.{BLOCKED}.43.224
  • {BLOCKED}.{BLOCKED}.170.65

  SOLUTION

Minimum Scan Engine:

9.850

FIRST VSAPI PATTERN FILE:

14.440.05

FIRST VSAPI PATTERN DATE:

08 Aug 2018

VSAPI OPR PATTERN File:

14.441.00

VSAPI OPR PATTERN Date:

08 Aug 2018

Step 1

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

Step 2

Note that not all files, folders, and registry keys and entries are installed on your computer during this malware's/spyware's/grayware's execution. This may be due to incomplete installation or other operating system conditions. If you do not find the same files/folders/registry information, please proceed to the next step.

Step 3

Remove the malware/grayware file dropped/downloaded by TROJ_MERETAM.E. (Note: Please skip this step if the threat(s) listed below have already been removed.)

     
    • %Application Data%\msdesk\FAQ
    • %Application Data%\msdesk\README.md
    • %Application Data%\msdesk\info.dat
    • %Application Data%\msdesk\Modules\systeminfo32
    • %Application Data%\msdesk\Modules\injectDll32
    • %Application Data%\msdesk\Modules\injectDll32_configs\dinj
    • %Application Data%\msdesk\Modules\injectDll32_configs\sinj
    • %Application Data%\msdesk\Modules\injectDll32_configs\dpost
    • %Application Data%\msdesk\Modules\networkDll32
    • %Application Data%\msdesk\Modules\networkDll32_configs\dpost
    • %Application Data%\\Microsoft\Windows\Recent\CustomDestinations\d93f411851d7c929.customDestinations-ms
    • %System%\Taks\MySysToken

Step 4

Scan your computer with your Trend Micro product to delete files detected as TROJ_MERETAM.E. 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 5

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.

  • %System%\Tasks\Microsoft\Windows Defender\MP Scheduled Scan


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