alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"ET RETIRED ISMAgent CnC Checkin 1"; flow:to_server,established; http.method; content:"GET"; http.uri; content:"/action2/"; fast_pattern; http.user_agent; content:"Firefox"; bsize:7; http.header_names; content:!"Referer|0d 0a|"; content:!"Accept"; reference:md5,a70a08a1e17b820c7dc8ee1247d6bfa2; reference:url,researchcenter.paloaltonetworks.com/2017/07/unit42-oilrig-uses-ismdoor-variant-possibly-linked-greenbug-threat-group/; classtype:command-and-control; sid:2024502; rev:5; metadata:affected_product Windows_XP_Vista_7_8_10_Server_32_64_Bit, attack_target Client_Endpoint, created_at 2017_07_28, deployment Perimeter, former_category MALWARE, malware_family Ismdoor, performance_impact Moderate, signature_severity Major, updated_at 2024_09_16, reviewed_at 2024_09_16;)