alert tcp $EXTERNAL_NET any -> $HOME_NET 21 (msg:"ET FTP HP-UX LIST command without login"; flow:established,to_server; flowbits:isnotset,ET.ftp.user.login; content:"LIST "; nocase; depth:5; reference:cve,2005-3296; reference:bugtraq,15138; classtype:attempted-recon; sid:2002851; rev:5; metadata:created_at 2010_07_30, confidence High, signature_severity Informational, updated_at 2019_07_26;)