alert tcp $HOME_NET any -> $EXTERNAL_NET 5222 (msg:"ET CHAT Facebook Chat using XMPP"; flow:to_server,established; content:"chat.facebook.com"; nocase; content:"jabber|3A|client"; nocase; distance:9; within:13; threshold:type limit, track by_src, count 1, seconds 60; reference:url,www.facebook.com/sitetour/chat.php; classtype:policy-violation; sid:2010819; rev:4; metadata:created_at 2010_07_30, signature_severity Informational, updated_at 2019_07_26;)