F-Secure
Tools
Trojan-Proxy:W32/Grum.A
Summary
This type of trojan allows unauthorized parties to use the infected computer as a proxy server to access the Internet anonymously.
Disinfection
Automatic Disinfection
Allow F-Secure Anti-Virus to disinfect the relevant files.
For more general information on disinfection, please see Removal Instructions.
Rootkit Detection
If the rootkit is hidden so that F-Secure Anti-Virus cannot detect its file, it is still possible to detect the malicious activity by scanning the system with a generic rootkit scanner, such as F-Secure BlackLight. The BlackLight utility is also able to disinfect computers that are infected by rootkits.
Allow F-Secure Anti-Virus to disinfect the relevant files.
For more general information on disinfection, please see Removal Instructions.
Rootkit Detection
If the rootkit is hidden so that F-Secure Anti-Virus cannot detect its file, it is still possible to detect the malicious activity by scanning the system with a generic rootkit scanner, such as F-Secure BlackLight. The BlackLight utility is also able to disinfect computers that are infected by rootkits.
Additional Details
Trojan-Proxy:W32/Grum.A may arrive in the system in a spam e-mail 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:
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.