alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"ET MALWARE DistTrack/Shamoon CnC Beacon M2"; flow:established,to_server; http.method; content:"GET"; http.uri; content:"."; content:"?"; distance:3; within:1; pcre:"/\.[a-z]{3}\?[a-z]+=(?:[A-Za-z0-9+/]{4})*(?:[A-Za-z0-9+/]{2}==|[A-Za-z0-9+/]{3}=|[A-Za-z0-9+/]{4})$/"; http.user_agent; content:"Mozilla/5.0 (MSIE 7.1|3b 20|Windows NT 6.0)"; fast_pattern; bsize:38; http.header_names; content:!"Accept"; content:!"Referer|0d 0a|"; reference:md5,5446f46d89124462ae7aca4fce420423; reference:md5,5bac4381c00044d7f4e4cbfd368ba03b; reference:url,researchcenter.paloaltonetworks.com/2016/11/unit42-shamoon-2-return-disttrack-wiper/; classtype:command-and-control; sid:2023571; rev:3; metadata:affected_product Windows_XP_Vista_7_8_10_Server_32_64_Bit, attack_target Client_Endpoint, created_at 2016_12_01, deployment Perimeter, malware_family DistTrack, malware_family Shamoon, signature_severity Major, tag c2, updated_at 2020_08_03, mitre_tactic_id TA0010, mitre_tactic_name Exfiltration, mitre_technique_id T1041, mitre_technique_name Exfiltration_Over_C2_Channel;)