alert tls $EXTERNAL_NET any -> $HOME_NET any (
msg:"ET ATTACK_RESPONSE Havoc/Sliver Framework TLS Certificate Observed";
flow:established,to_client;
tls.certs;
content:"|31 0b 30 09 06 03 55 04 06 13 02|US|31 13 30 11 06 03 55 04 08 13 0a|California|31 14 30 12 06 03 55 04 07 13 0b|Los Angeles|31 09 30 07 06 03 55 04 09 13 00 31 0d 30 0b 06 03 55 04 11 13 04|"; fast_pattern;
pcre:"/^\d{4}/R";
content:"|31 0d 30 0b 06 03 55 04 0a 13 04|corp"; nocase; within:15;
content:"|06 03 55 04 03|"; distance:4; within:5;
content:!"|2a 86 48 86 f7 0d 01 09 01|";
reference:url,github.com/BishopFox/sliver/blob/97d3da75b6e24defb3a2a97443a15a632b3a8448/server/certs/subject.go;
classtype:trojan-activity;
sid:2037489; rev:2;
metadata:affected_product Any, attack_target Client_and_Server, created_at 2022_07_07, deployment Perimeter, malware_family Sliver, malware_family Havoc, performance_impact Low, confidence High, signature_severity Major, updated_at 2024_01_03;
)