Analysis by: Jasen Sumalapao
ALIASES:

Exploit:Win32/CVE-2012-0158 (Microsoft), Trojan.Mdropper (Symantec), Exp/20120158-A (Sophos), Exploit.CVE-2012-0158.Gen (Bitdefender)

 PLATFORM:

Windows 2000, Windows XP, Windows Server 2003

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

  • Threat Type: Trojan

  • Destructiveness: No

  • Encrypted:

  • In the wild: Yes

  OVERVIEW

This Trojan arrives as an attachment to email messages spammed by other malware/grayware or malicious users. It arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.

It exploits software vulnerabilities to automatically execute attachments once a user reads or previews spammed messages. It does this action to allow easy execution of email attachments without the user opening the said attachments.

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: 127,408 bytes
File Type: RTF
Memory Resident: No
Initial Samples Received Date: 07 Aug 2012

Arrival Details

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

It 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 and executes the following files:

  • %User Temp%\{random filename}.exe - detected as TROJ_DAPATO.EVL

(Note: %User Temp% is the current user's Temp folder, which is usually C:\Documents and Settings\{user name}\Local Settings\Temp on Windows 2000, XP, and Server 2003.)

Propagation

This Trojan exploits the following software vulnerabilities to automatically execute attachments once a user reads or previews a spammed message:

  • CVE-2012-0158

Dropping Routine

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

  SOLUTION

Minimum Scan Engine: 9.200
FIRST VSAPI PATTERN FILE: 9.308.08
FIRST VSAPI PATTERN DATE: 07 Aug 2012
VSAPI OPR PATTERN File: 9.309.00
VSAPI OPR PATTERN Date: 08 Aug 2012

Step 1

For Windows XP and Windows Server 2003 users, before doing any scans, please make sure you disable System Restore to allow full scanning of your computer.

Step 2

Remove malware files dropped/downloaded by TROJ_ARTIEF.OU

    • TROJ_DAPATO.EVL

Step 3

Scan your computer with your Trend Micro product to delete files detected as TROJ_ARTIEF.OU. 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.

Step 4

Download and apply these security patches Refrain from using these products until the appropriate patches have been installed. Trend Micro advises users to download critical patches upon release by vendors.

  • http://technet.microsoft.com/en-us/security/bulletin/ms12-027


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