alert tcp $EXTERNAL_NET any -> $HOME_NET 110 (msg:"GPL POP3 XTND overflow attempt"; flow:to_server,established; content:"XTND"; nocase; isdataat:50,relative; pcre:"/^XTND\s[^\n]{50}/smi"; classtype:attempted-admin; sid:2101938; rev:5; metadata:created_at 2010_09_23, confidence Medium, signature_severity Major, updated_at 2019_07_26;)