Rule History

alert tls $HOME_NET any -> $EXTERNAL_NET any (msg:"ET INFO Observed RMM Domain in TLS SNI (system-monitor .com)"; flow:established,to_server; tls.sni; dotprefix; content:".system-monitor.com"; endswith; fast_pattern; reference:url,me.n-able.com/s/article/Take-Control-Standalone-Ports-and-Domains-Firewall-and-AV-Exclusions; reference:url,documentation.n-able.com/N-central/userguide/Content/ReleaseDocs/Install_Config/FirewallRequirements.htm; reference:url,ocumentation.n-able.com/remote-management/userguide/Content/risk_intelligence_external_links.htm; reference:url,documentation.n-able.com/remote-management/userguide/Content/dashboard_urls.htm; classtype:misc-activity; sid:2065088; rev:1; metadata:affected_product Windows_XP_Vista_7_8_10_Server_32_64_Bit, affected_product Windows_11, affected_product Windows_8, affected_product Windows_10, affected_product N_Able, attack_target Client_and_Server, created_at 2025_10_07, deployment Perimeter, performance_impact Low, confidence High, signature_severity Informational, tag RAT, tag RemoteAccessTool, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2025_10_07;)