alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"ET MALWARE Win32/Valak - Plugin Data Exfil"; flow:established,to_server; http.method; content:"POST"; http.uri; bsize:>60; content:"bm9uY2UyP"; fast_pattern; content:"cGx1Z2luP"; distance:55; 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:2029197; rev:1; metadata:affected_product Windows_XP_Vista_7_8_10_Server_32_64_Bit, attack_target Client_Endpoint, created_at 2019_12_23, deployment Perimeter, malware_family Win32_Valak, performance_impact Low, confidence High, signature_severity Major, updated_at 2019_12_23;)