alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"ET MALWARE GhostWriter APT Related Cobalt Strike Activity (GET)"; flow:established,to_server; http.method; content:"GET"; http.uri; content:"/works"; endswith; http.accept; bsize:16; content:"application/json"; http.content_type; content:"application/json|3b 20|charset=UTF-8"; startswith; http.cookie; content:"_token"; startswith; fast_pattern; pcre:"/^[a-zA-Z0-9\/+]{171}=$/R"; reference:url,cert.gov.ua/article/38155; reference:url,tria.ge/220324-p4dl5adghn; reference:url,twitter.com/netresec/status/1506990534547709972; reference:md5,b5525108912ee8d5f1519f1b552723e8; classtype:trojan-activity; sid:2035603; rev:3; metadata:attack_target Client_Endpoint, created_at 2022_03_24, deployment Perimeter, deployment SSLDecrypt, malware_family CobaltStrike, malware_family Ghostwriter, confidence Medium, signature_severity Major, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2024_04_15;)