Remember the DNSChanger botnet that we mentioned last month, which has been around for close to half a decade now? Most people who have it are either unaware that their machines have been infected, or they simply just don't care enough to clean it from their system.
As of May 2012, it was reported that over 350,000 machines were still infected with DNSChanger. A warning to get rid of it ensued, since the FBI is planning to shut down the legitimate replacement DNS servers they installed in place of the rogue ones on July 9th. Once this happens, people with infected computers will be redirected to spam and malware sites, effectively cutting themselves off from the Internet.
In an effort to help people with DNSChanger still on their machines to get rid of it, a group of websites and organizations on the web have set up the DNSChanger Working Group. Facebook is one of the sites that have signed on to take part in the group's efforts by displaying notifications to its users that might be using infected computers.
Facebook's security teams primary concern is keeping users safe. By partnering with the DNSChanger Working Group, Facebook is able to raise awareness about this particular malware. Of particular concern to everyone, is preventing users of infected computers from losing their access to the Internet on July 9, 2012.
-- Facebook Security
To check if your computer might be infected with the malware, head on over to the DNS Changer Check-Up site to run a quick scan. You can also download the DNS Check tool that F-Secure released recently that detects and cleans up your DNS settings if it finds any unauthorized modifications made to it.