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Trojan.Win32.MSISTAH.J

February 04, 2020
 Modified by: Mohammed Malubay
 ALIASES:

HEUR:Backdoor.Win32.Remcos.gen(KASPERSKY); Trojan.Win32.Injector(IKARUS);

 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:

357,746 bytes

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

28 Jan 2020

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:

  • %User Profile%\AppData\Roaming\IDMComp\Common\diskpart.exe

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

It drops the following files:

  • %User Temp%\nsnBF2.tmp
  • %User Temp%\notebookbarpopup.ui
  • %User Temp%\59.opends60.dll
  • %User Temp%\co6005fromstring.cs
  • %User Temp%\MakeZipExe.exe
  • %User Temp%\businesspatterns-3.gif
  • %User Temp%\CrmIntSdk.hxt
  • %User Temp%\function
  • %User Temp%\Satang
  • %User Temp%\adminicle.exe
  • %User Temp%\Brigalow.dll
  • %User Temp%\{random characters}.lnk --> targets the dropped copy

(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).)

Autostart Technique

This Trojan drops the following shortcut pointing to its copy in the User Startup folder to enable its automatic execution at every system startup:

  • diskpart.lnk

Other System Modifications

This Trojan modifies the following file(s):

  • %Windows%\win.ini

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

It adds the following registry entries:

HKEY_CURRENT_USER\Software\WIER1x (2.5)
(Default) = C:\Users\{user name}\AppData\Local\Temp

  SOLUTION

Minimum Scan Engine:

9.850

FIRST VSAPI PATTERN FILE:

15.648.03

FIRST VSAPI PATTERN DATE:

28 Jan 2020

VSAPI OPR PATTERN File:

15.649.00

VSAPI OPR PATTERN Date:

29 Jan 2020

Step 1

Trend Micro Predictive Machine Learning detects and blocks malware at the first sign of its existence, before it executes on your system. When enabled, your Trend Micro product detects this malware under the following machine learning name:

    Troj.Win32.TRX.XXPE50FFF034

Step 2

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 3

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 4

Restart in Safe Mode

[ Learn More ]

Step 5

Delete this registry value

[ Learn More ]

Important: Editing the Windows Registry incorrectly can lead to irreversible system malfunction. Please do this step only if you know how or you can ask assistance from your system administrator. Else, check this Microsoft article first before modifying your computer's registry.

  • In HKEY_CURRENT_USER\Software\WIER1x (2.5)
    • (Default) = C:\Users\{user name}\AppData\Local\Temp

Step 6

Search and delete this file

[ Learn More ]
There may be some files 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 Startup%\diskpart.lnk
  • %User Temp%\nsnBF2.tmp
  • %User Temp%\notebookbarpopup.ui
  • %User Temp%\59.opends60.dll
  • %User Temp%\co6005fromstring.cs
  • %User Temp%\MakeZipExe.exe
  • %User Temp%\businesspatterns-3.gif
  • %User Temp%\CrmIntSdk.hxt
  • %User Temp%\function
  • %User Temp%\Satang
  • %User Temp%\adminicle.exe
  • %User Temp%\Brigalow.dll
  • %User Temp%\{random characters}.lnk
  • %User Profile%\AppData\Roaming\IDMComp\Common\diskpart.exe

Step 7

Restart in normal mode and scan your computer with your Trend Micro product for files detected as Trojan.Win32.MSISTAH.J. 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 this Knowledge Base page for more information.

Step 8

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.


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