alert tcp $EXTERNAL_NET 5050 -> $HOME_NET any (msg:"GPL RETIRED Yahoo IM conference invitation"; flow:established,to_client; content:"YMSG"; depth:4; nocase; content:"|00 18|"; depth:2; offset:10; classtype:policy-violation; sid:2102453; rev:6; metadata:created_at 2010_09_23, former_category CHAT, confidence Medium, signature_severity Informational, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2026_08_28;)