Facebook admitted on Friday that unknown hackers had targeted it in a "sophisticated" cyber attack last month, but maintained that no user data was compromised during the breach.
Apparently, the social media outfit's systems were infected by malware after some of its employees had visited the website of a mobile app developer that was already compromised. In a blog post that discussed the attack in brief, the company also stated that all infected machines were fixed immediately and an investigation was launched.
According to Facebook, it was not the only company to have fallen victim to such an attack, but was one of the first few to have discovered and reported it. Currently, Facebook's security teams are working with those from other affected companies to find out more about the attack and the perpetrators.
"After analyzing the compromised website where the attack originated, we found it was using a "zero-day" (previously unseen) exploit to bypass the Java sandbox (built-in protections) to install the malware," read the blog post.
"Foremost, we have found no evidence that Facebook user data was compromised," it added.
In another security-related development, a US intelligence community report made available in the public domain earlier this week stated that the country was relentlessly being targeted by an enormous cyber espionage campaign.