TROJ_MDROPPR.NX

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.

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%\vmtools.exe - detected as BKDR_YART.A

(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, or C:\Users\{user name}\AppData\Local\Temp on Windows Vista and 7.)

It drops the following non-malicious file:

• %User Temp%\¥Ç©`¥¿¥µ¥ó¥×¥ë.xls

(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, or C:\Users\{user name}\AppData\Local\Temp on Windows Vista and 7.)

Dropping Routine

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

• (MS12-027) Vulnerability in Windows Common Controls Could Allow Remote Code Execution (2664258)

Other Details

This Trojan opens the following files:

• %User Temp%\¥Ç©`¥¿¥µ¥ó¥×¥ë.xls

(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, or C:\Users\{user name}\AppData\Local\Temp on Windows Vista and 7.)

NOTES:

When a machine is affected with this malware, MS Excel exits and runs again opening the non-malicious .XLS file to trick users into thinking that it is opening a normal .XLS file.