alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"ET MALWARE Win32/Valak <v9 Checkin"; flow:established,to_server; http.method; content:"GET"; http.uri; bsize:>60; content:"_bm9uY2U9"; fast_pattern; content:"dmVyc2lvbj"; distance:45; content:".html"; endswith; http.header_names; content:!"Referer"; reference:md5,c254b4f261a6f426c282ed8858a7bee0; reference:url,medium.com/@prsecurity_/casual-analysis-of-valak-c2-3497fdb79bf7; classtype:command-and-control; sid:2029192; 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 Low, confidence High, signature_severity Major, updated_at 2019_12_22;)