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JS_NEMUCOD.SMB

April 13, 2015
 Analysis by: Ryan Gardo
 ALIASES:

JS/Downloader.Agent(AVG); JS/JSDldr.V!tr(Fortinet); Trojan-Downloader.JS.Agent.hch(Kaspersky)

 PLATFORM:

Windows

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

  • Threat Type: Trojan

  • Destructiveness: No

  • Encrypted: No

  • 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:

8,432 bytes

File Type:

JS

Memory Resident:

No

Initial Samples Received Date:

23 Feb 2015

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.

Download Routine

This Trojan accesses the following websites to download files:

  • http://{BLOCKED}xedesign.com/document.php?id=545C535E0B0E05010A240D0A001605070B0914050A1D4A070B09&rnd=712221
  • http://{BLOCKED}edesign.com/document.php?id=545C535E0B0E05010A240D0A001605070B0914050A1D4A070B09&rnd=130772

It saves the files it downloads using the following names:

  • %User Temp%\78490338.exe
  • %User Temp%\85925084.exe

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

  SOLUTION

Minimum Scan Engine:

9.750

FIRST VSAPI PATTERN FILE:

11.548.05

FIRST VSAPI PATTERN DATE:

19 Mar 2015

VSAPI OPR PATTERN File:

11.549.00

VSAPI OPR PATTERN Date:

19 Mar 2015

Step 1

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 2

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

Step 3

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.
  • %User Temp%\78490338.exe
  • %User Temp%\85925084.exe

Step 4

Restart in normal mode and scan your computer with your Trend Micro product for files detected as JS_NEMUCOD.SMB. 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.


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