alert tcp $HOME_NET any -> $EXTERNAL_NET 5050 (msg:"GPL RETIRED Yahoo IM conference offer invitation"; flow:established,to_server; content:"YMSG"; depth:4; nocase; content:"|00|P"; depth:2; offset:10; classtype:policy-violation; sid:2102459; rev:7; metadata:created_at 2010_09_23, former_category CHAT, confidence Medium, signature_severity Informational, updated_at 2026_08_28;)