alert ftp $EXTERNAL_NET any -> $HOME_NET any (msg:"GPL FTP ALLO overflow attempt"; flow:to_server,established; content:"ALLO"; nocase; isdataat:100,relative; pcre:"/^ALLO\s[^\n]{100}/smi"; reference:bugtraq,9953; classtype:attempted-admin; sid:2102449; rev:3; metadata:created_at 2010_09_23, confidence Medium, signature_severity Major, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2019_07_26;)