alert tcp $EXTERNAL_NET any -> $HOME_NET 110 (msg:"GPL POP3 APOP overflow attempt"; flow:to_server,established; content:"APOP"; nocase; isdataat:256,relative; pcre:"/^APOP\s[^\n]{256}/smi"; reference:bugtraq,1652; reference:cve,2000-0840; reference:cve,2000-0841; reference:nessus,10559; classtype:attempted-admin; sid:2101635; rev:14; metadata:created_at 2010_09_23, cve CVE_2000_0840, confidence Medium, signature_severity Major, updated_at 2019_07_26;)