alert ftp $EXTERNAL_NET any -> $HOME_NET any (msg:"ET FTP USER login flowbit"; flow:established,to_server; content:"USER "; nocase; depth:5; flowbits:set,ET.ftp.user.login; flowbits:noalert; classtype:not-suspicious; sid:2002850; rev:5; metadata:created_at 2010_07_30, signature_severity Informational, updated_at 2019_07_26;)