alert tcp $EXTERNAL_NET any -> $HOME_NET 21 (msg:"ET INFO FTP Frequent Admin Login Attempts"; flow:established,to_server; content:"USER Admin|0d0a|"; nocase; threshold:type threshold, track by_src, count 3, seconds 30; classtype:attempted-admin; sid:2009668; rev:3; metadata:created_at 2010_07_30, confidence High, signature_severity Informational, updated_at 2024_03_06;)