With the July 9 Web apocalypse nearing for computer owners infected with the malicious DNSChanger malware, the social network reaches out to tell them how to clean their machines.

Don't be alarmed if you open up your Facebook account and get a large warning message that says, "Your computer or network might be infected."
Facebook announced today that its security team has joined a consortium of computer security experts working to clean up malicious malware called DNSChanger. As a result, the social network can now notify victims, who may have infected computers, and help them figure out how to rid their networks of the botnet.

"Facebook's Product Security Team is working constantly to protect users from malicious content and malware like viruses, trojans, and worms," Facebook wrote in a blog post today. "A recent malware threat our team has been fighting is called DNSChanger."
DNSChanger is a particularly diabolical botnet because those users with infected computers will no longer be able to access the Internet come July 9. That means no Web sites, no e-mail, and no Facebook.
When the malware was first discovered in 2007, it had already infected millions of computers worldwide. The way it worked was by tinkering with a computer's settings and then directing users to rogue servers set up by a crime ring. These servers then re-directed users to malicious Web sites.

Late last year, the FBI arrested the ring and seized the rogue servers. But since so many infected computers relied on the servers to reach the Internet, the agency opted not to shut them down and instead converted them to legitimate DNS machines. However, running the machines costs money, so the government decided to switch the servers off in July.
Facebook's effort to help users clean their computers comes on the heels of Google announcing the same last month. The Web giant has just begun posting alerts at the top of its search results page with text that says, "Your computer appears to be infected." Along with the notification, Google will also give users additional details on the malware.
If users get the Facebook warning or think that their computer is infected, they can visit the DNSChanger Working Group's Detection Page, which is the consortium that Facebook is working with, and get instructions on how to wipe their computer of the botnet.