Passtealer.W is a Trojan, which although seemingly inoffensive, can actually carry out attacks and intrusions.
It captures certain information entered or saved by the user, with the corresponding threat to privacy:
passwords saved by certain Windows services.
It sends the gathered information to a remote user by any available means: email, FTP, etc.
It uses several methods in order to avoid detection by antivirus companies:
- It terminates its own execution if it detects that it is being executed in a virtual machine environment, such as VMWare or VirtualPC.
- Its code is encrypted and it is only decrypted when it is going to run. Because of this, its code is not legible through a memory dump.
Passtealer.W does not spread automatically using its own means. It needs an attacking user's intervention in order to reach the affected computer. The means of transmission used include, among others, floppy disks, CD-ROMs, email messages with attached files, Internet downloads, FTP, IRC channels, peer-to-peer (P2P) file sharing networks, etc.