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JS_LOCKY.AGNS

August 29, 2016
 Analysis by: Michael Jay Villanueva
 ALIASES:

JS/Nemucod.ASB!tr.dldr (Fortinet); JS/Locky.AR (F-Protect); JS/TrojanDownloader.Nemucod.ASH (ESET-NOD32)

 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 as attachment to mass-mailed email messages.

It executes downloaded files whose malicious routines are exhibited by the affected system.

  TECHNICAL DETAILS

File Size:

51,974 bytes

File Type:

JS

Memory Resident:

No

Initial Samples Received Date:

24 Aug 2016

Arrival Details

This Trojan arrives as attachment to mass-mailed email messages.

Download Routine

This Trojan saves the files it downloads using the following names:

  • %User Temp%\MuLWehMe8gT
  • %User Temp%\MuLWehMe8gT.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.)

It executes downloaded files :

  • %User Temp%\MuLWehMe8gT.dll
    using this command: "%System%\rundll32.exe" {Malware Path and Filename},qwerty 323

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

whose malicious routines are exhibited by the affected system.

Other Details

This Trojan connects to the following possibly malicious URL:

  • http://dongguklee.{BLOCKED}o.to/samr1lp7
  • http://{BLOCKED}nepowers.us/crwtsb0
  • http://moussayer.{BLOCKED}l.be/8aju22
  • http://{BLOCKED}r.org/txb1n2bm
  • http://{BLOCKED}malw.ws/09n7n

  SOLUTION

Minimum Scan Engine:

9.800

VSAPI OPR PATTERN File:

12.735.00

VSAPI OPR PATTERN Date:

25 Aug 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%\MuLWehMe8gT
  • %User Temp%\MuLWehMe8gT.dll

Step 4

Scan your computer with your Trend Micro product to delete files detected as JS_LOCKY.AGNS. 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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