alert tls $EXTERNAL_NET any -> $HOME_NET any (msg:"ET INFO localhost .run TLS Certification Observed"; flow:established,to_client; tls.cert_subject; bsize:16; content:"CN=localhost.run"; fast_pattern; reference:url,localhost.run; classtype:misc-activity; sid:2039687; rev:2; metadata:attack_target Client_Endpoint, created_at 2022_11_04, deployment Perimeter, performance_impact Low, confidence High, signature_severity Informational, updated_at 2024_03_26;)