Danger worm hijacks Facebook accounts to inject banking Trojan

A dangerous worm is using Facebook to spread itself by posting malicious links on the social networking website that point to malware-tainted sites loaded with a variant of the Zeus banking Trojan as well as other nasties.

The malware uses stolen Facebook account credentials to log into compromised accounts and post links, according to security researchers at CSIS in Denmark, who were the first to detect the threat. The malicious links generated by the worm pose as links to a photo file posted by the account-holder's friend or online acquaintance.

In reality the file is a booby-trapped screensaver file with a .jpg file extension. Users have to download and open the file but if tricked into doing so, the consequences can be quite dire – especially since anti-virus detection rates are quite low.

CSIS added that the worm is also using other domains to spread. A write-up on the worm by GFI Software can be found here. CSIS initial alert (in Danish) is here.

The Danish security consultancy was the first to warn that source code for the formerly pricey ZeuS banking Trojan creation toolkit had leaked back in May. ®