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;
)