JS_LOCKY.DLDSAPA

 Analysis by: Cris Nowell Pantanilla

 ALIASES:

TrojanDownloader:JS/Nemucod (Microsoft), Trojan-Downloader.JS.Agent.mmo (Kaspersky), JS.Downloader (Symantec)

 PLATFORM:

Windows

 OVERALL RISK RATING:
 REPORTED INFECTION:

  • 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 executes the downloaded files. As a result, malicious routines of the downloaded files are exhibited on the affected system.

  TECHNICAL DETAILS

File Size:

62,933 bytes

File Type:

JS

Memory Resident:

No

Initial Samples Received Date:

19 Sep 2016

Payload:

Downloads files

Arrival Details

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

Download Routine

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

  • http://{BLOCKED}eimshi.com/cpboa
  • http://{BLOCKED}fid.com/z3zeg
  • http://{BLOCKED}awaac.net/wzwzjply

It saves the files it downloads using the following names:

  • %User Temp%\{random}.DLL - detected as Ransom_LOCKY.DLDSAOT

(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 then executes the downloaded files. As a result, malicious routines of the downloaded files are exhibited on the affected system.

Other Details

This Trojan does the following:

  • It executes the downloaded file using the following command:
    • rundll32.exe %User Temp%\{random}.DLL,qwerty 323

(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:

9.800

FIRST VSAPI PATTERN FILE:

12.786.08

FIRST VSAPI PATTERN DATE:

19 Sep 2016

VSAPI OPR PATTERN File:

12.787.00

VSAPI OPR PATTERN Date:

20 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

Remove malware/grayware files dropped/downloaded by JS_LOCKY.DLDSAPA. (Note: Please skip this step if the threats listed below have already been removed.)

Step 3

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