alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"ET MALWARE TrueBot/Silence.Downloader Keep-Alive"; flow:established,to_server; http.method; content:"GET"; http.uri; content:".php?dns="; fast_pattern; pcre:"/^[a-f0-9]{8}$/Rs"; http.header_names; content:"|0d 0a|Host|0d 0a 0d 0a|"; depth:10; endswith; reference:md5,c2a00949ddacfed9ed2ef83a8cb44780; classtype:trojan-activity; sid:2026560; rev:3; metadata:affected_product Windows_XP_Vista_7_8_10_Server_32_64_Bit, attack_target Client_Endpoint, created_at 2018_10_29, deployment Perimeter, malware_family TrueBot, malware_family Silence_Downloader, performance_impact Moderate, confidence High, signature_severity Major, updated_at 2020_09_16;)