alert tcp $HOME_NET any -> $EXTERNAL_NET any (msg:"ET MALWARE PCRat/Gh0st CnC Beacon Request (Xfire variant)"; flow:established,to_server; stream_size:server,=,1; content:"|58 66 69 72 65|"; startswith; content:!"|00 00|"; within:2; content:"|00 00|"; distance:2; within:2; content:!"|00 00|"; within:2; content:"|00 00|"; distance:2; within:2; byte_jump:4,5,little,from_beginning,post_offset -1; isdataat:!2,relative; reference:md5,7a55388f877ce40d2abf72ea5ee2a6b8; classtype:command-and-control; sid:2033731; rev:2; metadata:affected_product Windows_XP_Vista_7_8_10_Server_32_64_Bit, attack_target Client_Endpoint, created_at 2021_08_13, deployment Perimeter, malware_family Gh0st, malware_family PCRAT, performance_impact Low, confidence High, signature_severity Major, tag RAT, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2021_08_13;)