alert tls $EXTERNAL_NET any -> any any (msg:"ET MALWARE Possible DarkRats Tor Traffic"; flow:established,from_server; tls.cert_issuer; content:"CN=www"; startswith; content:".com"; endswith; pcre:"/^CN=www\.[0-9a-z]{8,20}\.com$/"; tls.cert_subject; content:"CN=www"; startswith; content:".net"; endswith; pcre:"/^CN=www\.[0-9a-z]{8,20}\.net$/"; xbits:isset,ET.ipcheck,track ip_dst; xbits:isset,ET.dropsite,track ip_dst; classtype:trojan-activity; sid:2033387; rev:2; metadata:attack_target Client_Endpoint, created_at 2021_07_22, deployment Perimeter, performance_impact Significant, confidence Medium, signature_severity Major, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2021_07_22, reviewed_at 2024_05_07;)