alert ftp $EXTERNAL_NET any -> $HOME_NET any (msg:"GPL FTP USER overflow attempt"; flow:to_server,established,no_stream; content:"USER|20|"; nocase; isdataat:100,relative; pcre:"/^USER\x20[^\x00\x20\x0a\x0d]{100}/smi"; reference:bugtraq,10078; reference:bugtraq,1227; reference:bugtraq,1504; reference:bugtraq,1690; reference:bugtraq,4638; reference:bugtraq,7307; reference:bugtraq,8376; reference:cve,1999-1510; reference:cve,1999-1514; reference:cve,1999-1519; reference:cve,1999-1539; reference:cve,2000-0479; reference:cve,2000-0656; reference:cve,2000-0761; reference:cve,2000-0943; reference:cve,2000-1035; reference:cve,2000-1194; reference:cve,2001-0256; reference:cve,2001-0794; reference:cve,2001-0826; reference:cve,2002-0126; reference:cve,2002-1522; reference:cve,2003-0271; reference:cve,2004-0286; classtype:attempted-admin; sid:2101734; rev:36; metadata:created_at 2010_09_23, cve CVE_1999_1510, confidence Medium, signature_severity Major, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2019_07_26;)