alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"ET USER_AGENTS Steam HTTP Client User-Agent"; flow:established,to_server; http.user_agent; content:"Valve/Steam HTTP Client"; depth:23; threshold:type limit, track by_src, count 1, seconds 300; classtype:policy-violation; sid:2028651; rev:2; metadata:affected_product Windows_XP_Vista_7_8_10_Server_32_64_Bit, attack_target Client_Endpoint, created_at 2019_10_07, deployment Perimeter, confidence High, signature_severity Informational, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2019_10_16;)