Analysis by: Michael Jay Villanueva

ALIASES:

TrojanDownloader:JS/Swabfex.P (Microsoft); JS/Nemucod.mt (McAfee); JS/TrojanDownloader.Nemucod.AVG (ESET-NOD32)

 PLATFORM:

Windows

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

  • Threat Type: Trojan

  • Destructiveness: No

  • Encrypted: Yes

  • In the wild: Yes

  OVERVIEW

Infection Channel: Spammed via email

This Trojan arrives as an attachment to email messages spammed by other malware/grayware or malicious users.

It does not have any propagation routine.

It does not have any backdoor routine.

  TECHNICAL DETAILS

File Size: 30,231 bytes
File Type: JS, Other
Memory Resident: No
Initial Samples Received Date: 06 Sep 2016

Arrival Details

This Trojan arrives as an attachment to email messages spammed by other malware/grayware or malicious users.

Propagation

This Trojan does not have any propagation routine.

Backdoor Routine

This Trojan does not have any backdoor routine.

Download Routine

This Trojan connects to the following website(s) to download and execute a malicious file:

  • http://www.{BLOCKED}s.{BLOCKED}t.ru/87b3ff3rc?ClKmkSII=GLdeUD -> Inaccessible
  • http://www.{BLOCKED}naomc.com/87b3ff3rc?ClKmkSII=GLdeUD - > Inaccessible
  • http://{BLOCKED}c.{BLOCKED}daancha.net/87b3ff3rc?ClKmkSII=GLdeUD -> Accessible
  • http://{BLOCKED}ppppsr.biz/js/87b3ff3rc?ClKmkSII=GLdeUD -> Inaccessible

It saves the files it downloads using the following names:

  • %User Temp%\ttqqcenUID1 ->temporary storage for encrypted downloaded file
  • %User Temp%\ttqqcenUID2 -> temporary storage for encrypted downloaded file
  • %User Temp%\ttqqcenUID3 -> temporary storage for encrypted downloaded file
  • %User Temp%\ttqqcenUID4 -> temporary storage for encrypted downloaded file
  • %User Temp%\ttqqcenUID1.dll -> decrypted file
  • %User Temp%\ttqqcenUID2.dll -> decrypted file
  • %User Temp%\ttqqcenUID3.dll -> decrypted file
  • %User Temp%\ttqqcenUID4.dll -> decrypted file

(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.)

Other Details

This Trojan does the following:

  • It executes the downloaded files using the following commands: "%System%\rundll32.exe" "%User Temp%\{filename}",qwerty
    where {filename} could be one of the following:
    • ttqqcenUID1.dll
    • ttqqcenUID2.dll
    • ttqqcenUID3.dll
    • ttqqcenUID4.dll

(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.)

NOTES:

It does not have rootkit capabilities.

It does not exploit any vulnerability.

  SOLUTION

Minimum Scan Engine: 9.800
FIRST VSAPI PATTERN FILE: 12.760.03
FIRST VSAPI PATTERN DATE: 06 Sep 2016
VSAPI OPR PATTERN File: 12.761.00
VSAPI OPR PATTERN Date: 07 Sep 2016

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

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%\ttqqcenUID1
  • %User Temp%\ttqqcenUID2
  • %User Temp%\ttqqcenUID3
  • %User Temp%\ttqqcenUID4
  • %User Temp%\ttqqcenUID1.dll
  • %User Temp%\ttqqcenUID2.dll
  • %User Temp%\ttqqcenUID3.dll
  • %User Temp%\ttqqcenUID4.dll

Step 4

Scan your computer with your Trend Micro product to delete files detected as JS_NEMUCOD.ELDSAOL. 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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