alert http $EXTERNAL_NET any -> $HOME_NET any (msg:"ET SCAN LeakIX Inbound User-Agent"; flow:established,to_server; http.user_agent; content:"|28|l9scan|2f|"; content:"|3b 20 2b|https|3a 2f 2f|leakix|2e|net"; fast_pattern; threshold:type limit, count 1, seconds 600, track by_src; reference:url,leakix.net; classtype:misc-activity; sid:2049255; rev:1; metadata:created_at 2023_11_20, deployment Perimeter, deployment SSLDecrypt, performance_impact Low, confidence High, signature_severity Informational, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2023_11_20;)