Analysis by: Cris Nowell Pantanilla
ALIASES:

Exploit:Win32/CVE-2015-1641 (Microsoft), MSWord/CVE_2015_1641!exploit (Fortinet), Exploit.MSWord.CVE-2012-0158.fx (Kasspersky)

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

  TECHNICAL DETAILS

File Size: 285,796 bytes
File Type: DOC
Memory Resident: No
Initial Samples Received Date: 19 Sep 2016
Payload: Drops files

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%\system.exe - detected as BKDR_ANDROM.YYSMM
  • %User Profile%\Local Settings\Temporary Internet Files\Content.Word\~WRO0000.doc - detected as TROJ_CVE20151641.BZC

(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.. %User Profile% is the current user's profile folder, which is usually C:\Documents and Settings\{user name} on Windows 2000, XP, and Server 2003, or C:\Users\{user name} on Windows Vista and 7.)

It takes advantage of the following software vulnerabilities to drop malicious files:

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

  SOLUTION

Minimum Scan Engine: 9.800
FIRST VSAPI PATTERN FILE: 12.786.06
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 TROJ_ANDROM.VTKK. (Note: Please skip this step if the threats listed below have already been removed.)

     BKDR_ANDROM.YYSMM

Step 3

Scan your computer with your Trend Micro product to delete files detected as TROJ_ANDROM.VTKK. 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. Microsoft Security Bulletin MS15-033


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