Analysis by: Rhena Inocencio
ALIASES:

Trojan:O97M/Madeba.A!det (Microsoft), VBA/TrojanDropper.Agent.BDO trojan (ESET)

 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 executes the dropped file(s). As a result, malicious routines of the dropped files are exhibited on the affected system.

  TECHNICAL DETAILS

File Size: Varies
File Type: DOC
Memory Resident: No
Initial Samples Received Date: 24 May 2016

Arrival Details

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

Dropping Routine

This Trojan drops the following files:

  • %User Temp%\harakiri.pfx - encoded harakiri.exe
  • %User Temp%\harakiri.exe - detected as TSPY_DRIDEX.YVD

(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 the dropped file(s). As a result, malicious routines of the dropped files are exhibited on the affected system.

Other Details

This Trojan does the following:

  • The embedded malicious macro code executes the following command to decode and execute a malicious binary:

    cmd /c certutil -decode %TMP%\harakiri.pfx %TMP%\harakiri.exe & start %TMP%\harakiri.exe

  SOLUTION

Minimum Scan Engine: 9.800
FIRST VSAPI PATTERN FILE: 12.546.06
FIRST VSAPI PATTERN DATE: 24 May 2016
VSAPI OPR PATTERN File: 12.547.00
VSAPI OPR PATTERN Date: 25 May 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

Remove the malware/grayware file dropped/downloaded by W2KM_DRIDEX.YVD. (Note: Please skip this step if the threat(s) listed below have already been removed.)

     
    • TSPY_DRIDEX.YVD

Step 4

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%\harakiri.pfx
  • %User Temp%\harakiri.exe

Step 5

Scan your computer with your Trend Micro product to delete files detected as W2KM_DRIDEX.YVD. 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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