Analysis by: Paulo Samson
 ALIASES:

TrojanDownloader:JS/Nemucod.G!MSR (MICROSOFT) ;

 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

Tipo de compactação: 40,293 bytes
Tipo de arquivo: JS
Data de recebimento das amostras iniciais: 21 Aug 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 files:

  • %ProgramData%\{Random Characters}.bat
  • %ProgramData%\{Random Characters}.bat
  • %ProgramData%\{Random Characters}.bat

(Note: %ProgramData% is a version of the Program Files folder where any user on a multi-user computer can make changes to programs. This contains application data for all users. This is usually C:\ProgramData on Windows Vista, 7, 8, 8.1, 2008(64-bit), 2012(64-bit) and 10(64-bit), or C:\Documents and Settings\All Users on Windows Server 2003(32-bit), 2000(32-bit) and XP.)

It adds the following processes:

  • "%System%\schtasks.exe" /Create /SC ONCE /TN {Random Characters} /TR "cmd /c \"start /min %ProgramData%\{Random Characters}.bat\"" /ST 20:52
  • "%System%\schtasks.exe" /Change /Disable /TN {Random Characters}
  • "%System%\schtasks.exe" /Delete /TN {Random Characters} /F
  • "%System%\schtasks.exe" /Create /SC ONCE /TN {Random Characters} /TR "cmd /c \"start /min %ProgramData%\{Random Characters}.bat\"" /ST 20:52
  • "%System%\schtasks.exe" /Delete /TN {Random Characters} /F
  • "%System%\schtasks.exe" /Create /SC ONCE /TN {Random Characters} /TR "cmd /c \"start /min %ProgramData%\{Random Characters}.bat\"" /ST 20:52
  • "%System%\schtasks.exe" /Delete /TN {Random Characters} /F

(Note: %ProgramData% is a version of the Program Files folder where any user on a multi-user computer can make changes to programs. This contains application data for all users. This is usually C:\ProgramData on Windows Vista, 7, 8, 8.1, 2008(64-bit), 2012(64-bit) and 10(64-bit), or C:\Documents and Settings\All Users on Windows Server 2003(32-bit), 2000(32-bit) and XP.)

Other Details

This Trojan connects to the following possibly malicious URL:

  • backup.{BLOCKED}ebooks.com
  • chs.{BLOCKED}arbari.com

  SOLUTION

Mecanismo de varredura mínima: 9.800
Primeiro arquivo padrão VSAPI: 16.180.01
Data do lançamento do primeiro padrão VSAPI: 21 Aug 2020
VSAPI OPR Pattern Version: 16.181.00
VSAPI OPR Pattern veröffentlicht am: 21 Aug 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:

     
    • Downloader.JS.TRX.XXJSE9EFF014

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

Search and delete these files

[ 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.
  • %ProgramData%\{Random Characters}.bat

Step 6

Restart in normal mode and scan your computer with your Trend Micro product for files detected as Trojan.JS.NEMUCOD.USMANHOFDM. 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.


Did this description help? Tell us how we did.