A computer security company on Tuesday warned Facebook users against clicking on a link claiming to be the “sexiest video ever” which is actually a trap designed to infect computers. The firm, Sophos, said that thousands of users have been hit by the malicious post, which appears to come from a friend’s Facebook account. The posting reads: “This is without doubt the sexiest video ever!” and is accompanied by what seems to be a movie thumbnail of a woman wearing a short skirt on an exercise bike.