alert tcp $EXTERNAL_NET any -> $HOME_NET 21 (msg:"GPL FTP CWD ..."; flow:to_server,established; content:"CWD"; nocase; content:"..."; distance:0; pcre:"/^CWD\s[^\n]*?\.\.\./smi"; reference:bugtraq,9237; classtype:bad-unknown; sid:2101229; rev:8; metadata:created_at 2010_09_23, signature_severity Unknown, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2019_07_26;)