alert tcp $EXTERNAL_NET any -> $HOME_NET any (msg:"ET CHAT Yahoo IM conference watch"; flow:from_server,established; content:"|0D 00 05 00|"; depth:4; classtype:policy-violation; sid:2001264; rev:5; metadata:created_at 2010_07_30, signature_severity Informational, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2019_07_26;)