alert tcp any any -> any 21 (msg:"ET SCAN Grim's Ping ftp scanning tool"; flow:to_server,established; content:"PASS "; content:"gpuser@home.com"; within:18; reference:url,archives.neohapsis.com/archives/snort/2002-04/0448.html; reference:url,grimsping.cjb.net; classtype:network-scan; sid:2007802; rev:4; metadata:created_at 2010_07_30, confidence Medium, signature_severity Informational, updated_at 2019_07_26;)