alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"ET MALWARE Possible Turla Carbon Paper CnC Beacon (Fake User-Agent)"; flow:established,to_server; http.method; content:"GET"; http.header; content:"."; distance:1; within:2; content:".0|3b 20|Windows NT|20|"; distance:0; content:"Trident/"; distance:0; http.user_agent; pcre:"/^Mozilla\/4\.0\x20\(compatible\x3b\x20MSIE\x20\d{1,2}\.0\.\d+\.\d+\.0\x3b\x20Windows\x20NT\x20/"; content:"Mozilla/4.0 (compatible|3b 20|MSIE|20|"; startswith; http.start; content:"Cookie|3a 20|PHPSESSID="; fast_pattern; http.header_names; content:"Referer|0d 0a|"; reference:url,www.welivesecurity.com/2017/03/30/carbon-paper-peering-turlas-second-stage-backdoor/; classtype:command-and-control; sid:2024183; rev:6; metadata:affected_product Windows_XP_Vista_7_8_10_Server_32_64_Bit, attack_target Client_Endpoint, created_at 2017_04_06, deployment Perimeter, performance_impact Significant, confidence Medium, signature_severity Major, tag c2, updated_at 2024_04_22, mitre_tactic_id TA0010, mitre_tactic_name Exfiltration, mitre_technique_id T1041, mitre_technique_name Exfiltration_Over_C2_Channel;)