Facebook users are once again being targeted in malware attacks and are warned to exercise caution when clicking on links in wall posts, following an attempt by hackers to infect computers by spreading messages containing malicious links on the popular social networking web site.
Messages left on Facebook users' walls are urging members to view a video (which pretends to be hosted on a Google website), but clicking on the link and visiting the webpage actually takes users to a site which asks them to download an executable to watch the movie. Sophos warns that the dangerous Facebook messages include a link to a third party website of the form: 'h__p://www.google.com.id. [removed] .cn/gallery.php?id=…'
The executable file, detected by Sophos as the Troj/Dloadr-BPL Trojan horse, then downloads further malicious code (detected as Troj/Agent-HJX), and displays an innocent image of a court jester sticking his tongue out.
"Clicking on links in messages can lead to a malware infection, whether the messages are in your email or on a site like Facebook. There has been a flurry of malicious e-mails recently posing as links to videos – so there's really no excuse not to know that this trick is being commonly used by hackers at the moment," says Brett Myroff, CEO of regional Sophos distributor, Sophos South Africa.
"Companies will once again be considering whether it's time to block Facebook in the workplace – not just for the usual productivity reasons, but because of the security threats that sites like this may pose to their organisation."
Sophos experts believe that businesses need to set policies regarding Facebook usage, and implement web security solutions, to prevent dangers entering the workplace.
"Companies need to make up their own mind as to whether their users should be allowed to access websites like Facebook and MySpace during office hours. If workers are allowed access to these sites, then it's vital that they do not put their personal and corporate data at risk, and that they are fully secured against web-based infections," says Myroff. "The best defence is for businesses to protect themselves with a web security and control appliance which can filter internet access and prevent the downloading of malicious code."