The Syrian Telecom Ministry launched a man-in-the-middle attack against the HTTPS version of the Facebook site. The attack is not extremely sophisticated: the certificate is invalid in user’s browsers, and raises a security warning. The certificate was not signed by a Certificate Authority that was trusted by users’ web browsers. The security warning is users’ only line of defense, and many governments have the capability to perform versions of this attack that do not raise errors or warnings. We cannot confirm the identity of the perpetrators.
Source: https://thehackernews.com/2011/05/syrian-man-in-middle-attack-against.html