Bropia.F is a minor variant of Bropia.A. Like the previous variants, it uses MSN messenger for spreading. It also drops a variant of Rbot on the infected system.
Once detected, the F-Secure security product will automatically disinfect the suspect file by either deleting it or renaming it.
When run, the worm copies itself as "msnus.exe" in the Windows system directory. Then it checks files:
winhost.exe winis.exe dnsserv.exe
If these files are not found, it drops file "cz.exe" and executes it. This file is a variant of Rbot. When "cz.exe" is run, it copies itself as "winhost.exe" in the Windows system directory and adds the following registry keys:
[HKLM\Software\Microsoft\Windows\CurrentVersion\Run] "win32" = "%SysDir%\winhost.exe"
This ensures that it will be executed at next system startup. The bot can be used as a backdoor, collecting system information, logging keystrokes, relaying spam and for various other purposes.Brobia.F also drops a file "sexy.jpg" and opens it. On default installation of Windows, the program associated with jpg-extension is usually Internet Explorer. When opened with Internet Explorer, the picture looks like this:
The worm copies itself in C-directory using one of the following filenames:
LOL.scr Webcam.pif bedroom-thongs.pif naked_drunk.pif LMAO.pif ROFL.pif underware.pif Hot.pif new_webcam.pif
Then it attempts to send this file using MSN messenger to all active MSN contacts. The recipient has to accept and open the file to get infected by the worm.
F-Secure Anti-Virus detects Brobia.F with the following update:
Detection Type: PC
Technical Details: Jarkko Turkulainen, Feb 03rd, 2005