W32.Pilleuz is a worm that may open a backdoor on compromised computer allowing a remote author to gain unauthorized access. The worm may access local files, download files, execute commands, modify Hosts file and steal web browser’s information. W32.Pilleuz can flood Internet traffic to various web sites that causes distributed denial of service (DDoS) attack.
Alias: W32/Autorun.worm!a758e0e7, W32/Rimecud, W32/Autorun-AUP, ButterflyBot.A, Metulji
Damage Level: Medium
Systems Affected: Windows 9x, 2000, XP, Windows Vista
To be more effective and contagious, the worm will inject itself to processes like explorer.exe and iexplore.exe. It will establish a connection using UDP packets to its various remote servers to performs the following tasks:
- Download and execute additional malware on the infected PC
- Download an update for itself
- Gathers sensitive information such as user name, password and online banking details
- Monitors web browsing activity
W32.Pilleuz utilizes Windows Autorun functionality that automatically runs itself when an infected drive is accessed. Then, it will look for other removable drives on the computer and drops the same executable and configuration files. The worm spreads to other system when the infected removable drive is attached.
File-sharing network is another distribution channel for this worm. Malicious code is intentionally injected to some legitimate executable file and shared over to other users of peer-to-peer network. To intensify infection, authors of this worm uses downloadable files that are frequently requested by people such as games, popular software, serials and key generators.
The worm also tries to propagate via MSN Messenger chat program. It sends a customized messages containing malicious link to victim’s contact list. The link points to a location where copy of the worm is being hosted.