alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"ET RETIRED TrueBot/Silence.Downloader CnC Checkin 4"; flow:established,to_server; http.method; content:"POST"; http.uri; content:".php"; endswith; http.request_body; content:"q="; depth:2; pcre:"/^q=(?:[A-Za-z0-9+/]{4})*(?:[A-Za-z0-9+/]{2}==|[A-Za-z0-9+/]{3}=|[A-Za-z0-9+/]{4})$/i"; http.user_agent; content:"Mozilla/112.0"; startswith; fast_pattern; http.header_names; content:!"Referer"; content:!"Accept"; reference:md5,f1a4e74e72390ef98c23f19589d3c7cd; reference:url,blog.talosintelligence.com/breaking-the-silence-recent-truebot-activity/; classtype:command-and-control; sid:2045299; rev:2; metadata:affected_product Windows_XP_Vista_7_8_10_Server_32_64_Bit, attack_target Client_Endpoint, created_at 2023_05_02, deployment Perimeter, deployment SSLDecrypt, former_category MALWARE, malware_family TrueBot, performance_impact Low, confidence High, signature_severity Major, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2025_04_17, reviewed_at 2025_04_17; target:src_ip;)