Facebook security flaw allowed hackers to alter Messenger conversations

A security flaw in Facebook's Messenger, discovered by online security company Check Point Software Technologies, allowed a malicious user to alter the messages in a Facebook chat after they were sent. 

In one scenario, this could allow someone to send you an innocuous link in a Facebook chat, and later change it to a link that leads to a malware installation package, tricking you into infecting your system. 

The exploit, explained in detail over at the Check Point blog, consists of finding a message's unique "message_id" identifier, then altering the message content and sending it back to Facebook which accepts the new content as genuine, without alerting the recipient of the change.  Read more...