alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"ET MALWARE Win32/HydraCrypt CnC Beacon 3"; flow:established,to_server; http.method; content:"GET"; http.uri; content:"/upd.php"; fast_pattern; endswith; http.header; pcre:"/^(?:Referer\x3a[^\r\n]+\r\n)?Host\x3a[^\r\n]+[\r\n]+$/"; http.header_names; content:!"User-Agent|0d 0a|"; content:!"Accept"; reference:md5,046e4b3ff7b323f2147f2d5d43b7e5f4; reference:md5,e4ab12da8828a7f1e6c077a2999f8320; classtype:command-and-control; sid:2020503; rev:6; metadata:attack_target Client_Endpoint, created_at 2015_02_24, deployment Perimeter, malware_family Win32_HydraCrypt, signature_severity Major, tag c2, updated_at 2020_10_07, mitre_tactic_id TA0010, mitre_tactic_name Exfiltration, mitre_technique_id T1041, mitre_technique_name Exfiltration_Over_C2_Channel;)