alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"ET MALWARE OilRig OopsIE CnC Checkin M4"; flow:established,to_server; http.method; content:"GET"; http.uri; content:"/khc?"; depth:5; fast_pattern; pcre:"/^[A-F0-9]{10,}$/Ri"; http.accept_enc; content:"gzip, deflate"; endswith; http.header_names; content:"User-Agent"; content:!"Referer"; reference:url,researchcenter.paloaltonetworks.com/2018/09/unit42-oilrig-targets-middle-eastern-government-adds-evasion-techniques-oopsie/; classtype:command-and-control; sid:2026083; rev:3; metadata:affected_product Windows_XP_Vista_7_8_10_Server_32_64_Bit, attack_target Client_and_Server, created_at 2018_09_05, deployment Perimeter, malware_family OilRig, malware_family OopsIE, performance_impact Low, confidence High, signature_severity Major, tag APT, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2020_09_16;)