Analysis by: Jennifer Gumban
 PLATFORM:

Windows 2000, Windows Server 2003, Windows XP (32-bit, 64-bit), Windows Vista (32-bit, 64-bit), Windows 7 (32-bit, 64-bit)

 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 takes advantage of software vulnerabilities to allow a remote user or malware/grayware to download files. It executes the downloaded files. As a result, malicious routines of the downloaded files are exhibited on the affected system. As of this writing, the said sites are inaccessible.

  TECHNICAL DETAILS

File Size: 45,207 bytes
File Type: DOCX
Memory Resident: No
Initial Samples Received Date: 19 Apr 2016
Payload: Connects to URLs/IPs, 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 takes advantage of the following software vulnerabilities to allow a remote user or malware/grayware to download files:

  • Office Buffer Overflow Vulnerability (CVE-2013-1331)

After successfully exploiting the said vulnerability, this malware connects to the following URLs to possibly download other malicious files:

  • http://www.{BLOCKED}nglinks.com/somebody/4688/space.gif..............................................................................................................................................php?a=95146-555210c567278074917c1d11f25a6221

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

As of this writing, the said sites are inaccessible.

NOTES:

This malware uses XML Tag Relationship as a technique to download resources.

  SOLUTION

Minimum Scan Engine: 9.800
FIRST VSAPI PATTERN FILE: 12.476.02
FIRST VSAPI PATTERN DATE: 19 Apr 2016
VSAPI OPR PATTERN File: 12.477.00
VSAPI OPR PATTERN Date: 19 Apr 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

Scan your computer with your Trend Micro product to delete files detected as TROJ_CVE20131331.EA. 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 3

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.


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