alert tcp $HOME_NET any -> $EXTERNAL_NET any (msg:"ET HUNTING HTTP GET Request XOR Key 81"; flow:established,to_server; content:"|c6 c4 d5 a1 ae|"; startswith; fast_pattern; content:"|a1 c9 d5 d5 d1 ae|"; distance:0; classtype:misc-activity; sid:2038093; rev:2; metadata:attack_target Client_and_Server, created_at 2022_08_09, deployment Perimeter, performance_impact Low, confidence Medium, signature_severity Informational, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2022_08_10, mitre_tactic_id TA0005, mitre_tactic_name Defense_Evasion, mitre_technique_id T1027, mitre_technique_name Obfuscated_Files_or_Information;)