Facebook, experts spar over Ramnit worm contagion
Security boss says stalking site is free of bank account-raiding malware
Facebook has downplayed the significance of Ramnit, a recently discovered worm that attempts to steal login credentials for the social networking site.
It said an adapted version of the bank account-raiding virus is not actually spreading through the site itself. However Seculert, the security biz that discovered a Ramnit command-and-control server earlier this month, maintains that the malware is spreading on Facebook via links to websites that exploit security holes to infect machines.
Seculert's claim is contrary to Facebook's insistence that it is free of Ramnit-related malicious spam:
Recently, Facebook Security has become aware of a variant of the Ramnit virus that injects malicious HTML into the Facebook login page. We have spent time investigating the malware and have not seen any capability, thus far, for the virus to spam and propagate via Facebook.
Additionally, we have built robust internal systems that validate every single login to our site, regardless if the password is correct or not, to check for malicious activity. By analyzing every single login to the site we have added a layer of security that protects our users from threats both known and unknown. Beyond our engineering teams that build tools to block malware we also have a dedicated enforcement team that seeks to identify those responsible for threats and works with our legal team to ensure appropriate consequences follow.
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.
Aviv Raff, CTO at Seculert, took issue with aspects of Facebook's statement while endorsing its more general security advice.
"We've never said or wrote that the malware injects HTML on Facebook pages. We did say however that it steals information, [primarily] Facebook login credentials (but not only Facebook)," Raff told El Reg.
"There is no reason for the Ramnit authors to have the malware stealing specifically Facebook login credentials beside using those stolen credentials to spread their own malware, or selling them to others who will do the same."
"I agree with the suggestion for their users. People should be careful clicking on links, even if they are part of a status of their Facebook friends. This is the same with links in emails (even if the email is coming from someone you know)," he added.
Raff stood by his earlier theory that Ramnit is spreading by using stolen account credentials to post malicious links on Facebook.
"Yes, we still suspect that the attackers behind Ramnit used those credentials to spread the malware via malicious links," Raff said.
"The malware is still being used to steal Facebook credentials from its victims, so Facebook staff and users should keep an eye for such links," he concluded.
Ramnit started as a file infector worm that stole FTP credentials and browser cookies, first appearing online around April 2010. Variants of the malware accounted for 17.3 per cent of all new malicious software infections by July 2011, according to Symantec.
Bank account credential stealing capabilities, lifted from the source leak of the even more infamous ZeuS cybercrime toolkit, were added last summer. The addition of Facebook sniffing capabilities represents the latest innovation.
"The malware steals information from the victim. Any form the user enters (e.g. login to Facebook or a bank, sending email via webmail, etc.) is sent to the Ramnit C&C [command and control] server," Raff explained.
This C&C server parses information and extracts the Facebook credentials, and puts it in a file called facebook_accounts.txt (as explained in a blog post by Seculert here).
Seculert passed on the 45,000 passwords and associated email addresses it recovered from a Ramnit C&C server to Facebook. Most of these account login credentials covered UK and French users. Facebook, as previously reported, said the "majority of the information was out of date" while promising to initiate remedial steps to restore potentially compromised accounts. ®