alert tcp $EXTERNAL_NET any -> $HOME_NET 21 (msg:"ET EXPLOIT FTP .message file write"; flow:to_server,established; content:"STOR "; nocase; depth:5; content:".message|0d 0a|"; distance:0; pcre:"/[^a-zA-Z0-9]+\.message/"; flowbits:set,BE.ftp.message; reference:url,www.milw0rm.com/exploits/2856; classtype:misc-attack; sid:2003196; rev:7; metadata:created_at 2010_07_30, signature_severity Major, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2019_07_26;)