alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"ET MALWARE Win32/Valak <v9 - Stage 2 - Request"; flow:established,to_server; http.method; content:"GET"; http.uri; bsize:>60; content:"_aWQ9"; fast_pattern; content:".html"; endswith; pcre:"/_aWQ9[a-zA-Z0-9\/]{43,46}(?:JmdpZD|Z2lkP|ZnaWQ9)/"; http.header_names; content:!"Referer"; reference:md5,c254b4f261a6f426c282ed8858a7bee0; reference:url,medium.com/@prsecurity_/casual-analysis-of-valak-c2-3497fdb79bf7; classtype:command-and-control; sid:2029193; rev:2; metadata:affected_product Windows_XP_Vista_7_8_10_Server_32_64_Bit, attack_target Client_Endpoint, created_at 2019_10_22, deployment Perimeter, malware_family Win32_Valak, performance_impact Moderate, confidence High, signature_severity Major, updated_at 2020_12_10;)