Summary

Bropia.G is a new variant of Bropia worm. Like the previous variants, it uses MSN messenger for spreading. It also drops a variant of Rbot on the infected system.

Additional Details

When run, the worm checks for file "nvsc32.exe". This check is made to prevent the worm for installing it again on infected system. If "nvsc32.exe" is not found, it drops file "exe.exe" and executes it. This file is a variant of Rbot. When "exe.exe" is run, it copies itself as "nvsc32.exe" in the Windows system directory and installs itself on system. It adds the following registry keys to ensure it will be run on the next system startup:

 
 
 [HKLM\System\CurrentControlSet\Services]
 [HKLM\Software\Microsoft\Windows\CurrentVersion\Run]
 [HKLM\Software\Microsoft\Windows\CurrentVersion\RunOnce]
 [HKCU\Software\Microsoft\Windows\CurrentVersion\Run]
 [HKCU\Software\Microsoft\Windows\CurrentVersion\RunOnce]
 "NvCplScan" = "%SystemDir%\nvsc32.exe"

The bot can be used as a backdoor, collecting system information, logging keystrokes, relaying spam and for various other purposes. Brobia.G also drops a file "pic.jpg" and opens it. On default installation of Windows, the program associated with jpg-extension is usually Internet Explorer. This file presents a woman in handcuffs.

MSN spreading

The worm attempts to send one of the following messages to MSN Messenger contacts:

 
 
 LOOK!  <URL to worm> :-O
 wtf....<URL to worm> :D
 OMFG!  <URL to worm> :P
 LMFAO! <URL to worm> :P

Where <URL to worm> is a http-link to worm's file. The link is static address. At the time of this writing, the file has been removed from the server.

Detection

F-Secure Anti-Virus detects Brobia.G with the following update: [FSAV_Database_Version] Version=2005-02-16_01

Technical Details: Jarkko Turkulainen, Feb 16rd, 2005; F-Secure Corporation