A bank account-raiding worm has started spreading on Facebook, stealing login credentials as it creeps across the site, security researchers have revealed.
Evidence recovered from a command-and-control server used to coordinate the evolving Ramnit worm confirms that the malware has already stolen 45,000 Facebook passwords and associated email addresses. Experts from Seculert, who found the controller node, have supplied Facebook with a list of all the stolen credentials found on the server. Most of the victims are from either the UK or France.
Ramnit differs from other worms, such as Koobface, that have used Facebook to spread because it relies on multiple infection techniques and has only recently extended onto social networks. Koobface, by contrast, only uses Facebook or Twitter to spread.
"Ramnit started as a file infector worm which steals FTP credentials and browser cookies, then added some financial-stealing capabilities, and now recently added Facebook worm capabilities," Aviv Raff, CTO at Seculert, told El Reg.
"We suspect that they use the Facebook logins to post on a victim's friends' wall links to malicious websites which download Ramnit," he added.
Ramnit first appeared in April 2010. By last July variants of the malware accounted for 17.3 per cent of all new malicious software infections, according to Symantec. A month later Trusteer reported that flavours of Ramnit were packing sophisticated banking login credential snaffling capabilities - technologies culled from the leak of the source code of the notorious ZeuS cybercrime toolkit at around the same time.
The new Ramnit configuration was able to bypass two-factor authentication and transaction-signing systems used by financial institutions to protect online banking sessions. The same technology might also be used to bypass two-factor authentication mechanisms in order to gain remote access to corporate networks, Seculert warns.
Invading Zuckerberg's Reservation
The move onto Facebook by the miscreants behind Ramnit seems designed primarily to expand the malware's distribution network and infect more victims.
"We suspect that the attackers behind Ramnit are using the stolen credentials to expand the malware’s reach," Seculert concludes, adding that capturing the login credentials of Facebook accounts creates a means to attack more sensitive accounts that happen to use the same email address and password combination.
"The cyber-criminals are also taking advantage of the fact that people usually use the same passwords for different web-based services (Facebook, Gmail, Corporate SSL VPN, Outlook Web Access, etc.) to gain remote access to corporate networks," it said.
The Ramnit outbreak on Facebook follows the November outbreak of an earlier worm that tried to infect victims with a variant of ZeuS.
"More and more malware families have started using social networks to reach victims instead of spam," Raff added.
In a statement, Facebook said it was applying security measures to contain the problem.
“Last week we received from external security researchers a set of user credentials that had been harvested by a piece of malware. Our security experts have reviewed the data, and while the majority of the information was out-of-date, we have initiated remedial steps for all affected users to ensure the security of their accounts. Thus far, we have not seen the virus propagating on Facebook itself, but have begun working with our external partners to add protections to our anti-virus systems to help users secure their devices. People can protect themselves by never clicking on strange links and reporting any suspicious activity they encounter on Facebook. We encourage our users to become fans of the Facebook Security Page (www.facebook.com/security) for additional security information.