Trojan-Proxy:W32/Grum.A

Trojan-Proxy:W32/Grum.A may arrive in the system in a spam email message containing an image that links to the real malware.

Here is the image associated with the message:

This malware is hosted at the following links:

• http://tvz-archive.com/I[REMOVED}.exe
• http://abnoba.net/I[REMOVED]0.exe

Installation

If the user executes the file they are directed to by the spam message, it creates a copy of itself on the user's computer at the following path and filename:

• %temp%\winlogon.exe

Grum.A uses the following batch file created on the same directory where the malware was to delete the executed copy of itself:

• sys.bat

To enable automatic execution upon system boot, it adds the following auto start registry:

• HKCU\\Software\Microsoft\Windows\CurrentVersion\Run Firewall auto setup = %temp%\winlogon.exe

Note: %temp% is the temporary windows folder:

Activity

Once installed, Grum.A serves as a proxy server that communicates to the following address:

• 72.232.49.214

Commands from the server may include downloading of files and spamming mails.

Stealth

Grum.A is a kernel malware that hooks several ntdll APIs to hide its file and process.