Analysis by: Jennifer Gumban
ALIASES:

TrojanDownloader:O97M/Adnel (Microsoft), W97M/Downloader.atg (McAfee), Trojan-Downloader.MSWord.Agent.xw (Kaspersky), Troj/DocDl-ANF (Sophos)

 PLATFORM:

Windows

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

  • Threat Type: Trojan

  • Destructiveness: No

  • Encrypted:

  • In the wild: Yes

  OVERVIEW

Infection Channel: Downloaded from the Internet, Dropped by other malware

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.

However, as of this writing, the said sites are inaccessible.

  TECHNICAL DETAILS

File Size: 82,432 bytes
File Type: XLS
Memory Resident: No
Initial Samples Received Date: 16 Dec 2015
Payload: Connects to URLs/IPs

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:

  • %User Temp%\thestrong.exe - detected as BKDR_DRIDEX.CP

(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 connects to the following possibly malicious URL:

  • http://{BLOCKED}mpsroumain.org/98g654d/4567gh98.exe
  • http://{BLOCKED}g.{BLOCKED}t.t-online.de/98g654d/4567gh98.exe

However, as of this writing, the said sites are inaccessible.

  SOLUTION

Minimum Scan Engine: 9.800
FIRST VSAPI PATTERN FILE: 12.214.07
FIRST VSAPI PATTERN DATE: 16 Dec 2015
VSAPI OPR PATTERN File: 12.215.00
VSAPI OPR PATTERN Date: 17 Dec 2015

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 X2KM_DRIDEX.YYSPX. (Note: Please skip this step if the threats listed below have already been removed.)

     
    • BKDR_DRIDEX.CP

Step 3

Scan your computer with your Trend Micro product to delete files detected as X2KM_DRIDEX.YYSPX. 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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