Check Point Software Technologies discovered a flaw in Facebook’s chat system that made it possible for an attacker to modify or remove any sent message, photo, file or link in a conversation they were part of. If attackers are somehow able to gain control of someone else’s PC or Facebook account, then they are also able to modify all of that person’s chat histories with other Facebook users. Facebook has rewritten its past code to fix the flaw since being informed of it earlier this month, the security company said.”]