alert tcp $EXTERNAL_NET any -> $HOME_NET any (msg:"ET RETIRED Yahoo IM conference watch"; flow:established,to_client; content:"|0D 00 05 00|"; depth:4; classtype:policy-violation; sid:2001264; rev:7; metadata:created_at 2010_07_30, former_category CHAT, confidence Medium, signature_severity Informational, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2026_08_28;)