The social networking site said that hackers had recently infiltrated computers of some of its employees, although no user date was compromised assured the company.
An official statement from Facebook said: “As soon as we discovered the presence of the malware, we remediated all infected machines, informed law enforcement, and began a significant investigation that continues to this day.”
The actual attack on Facebook came three days before the US presidential election but the company have only now decided to release the information about the attack to the social networking site.
Facebook have not confirmed why they waited until now to reveal the attack and according to news agency Reuters, the source of the attack is believed to have come from China.
The attack highlights the potential problems of having over one billion users and the threat of user information being compromised through hackers.
Facebook are not the only company to have been the recent victim of a hack with microblogging site Twitter also stating that they had been hacked earlier this month with around 250,000 users accounts being potentially compromised.
President Barack Obama stated earlier this week that he was seeking better protection of Americas critical infrastructure to protect it from future cyber attacks from other countries.
In their statement Facebook noted that they had not been the only site to be attacked but refused to name the other victims and simply said: “others were attacked and infiltrated recently as well.”
The cyber attack was described by Facebook as being a “zero-day” attack, a form of hacking that is thought to be the most dangerous and sophisticated. Zero day attacks are known for them being very difficult to detect with many people not even realising that they have been attacked. Zero Day attacks are also very costly to launch and usually suggest some form of government involvement according to Reuters.
The hack was spotted by Facebook after the company noticed a suspicious file on the laptop of an employee. This file was then forensically examined and identified as a malicious file which led to a company wide search uncovering “several other compromised employee laptops”.
To try and protect further cyber attacks in the future and to guard the information held by Facebook on their users the company announced that new protections were added to Facebook on February 1.
In January 2010, Google was the victim of a Zero Day attack with source code from the attack once again being traced back to China. This led to Google reducing its operations in China.