alert ftp $EXTERNAL_NET any -> $HOME_NET any (msg:"ET EXPLOIT VSFTPD Backdoor User Login Smiley"; flow:established,to_server; content:"USER "; depth:5; content:"|3a 29|"; distance:0; classtype:attempted-admin; sid:2013188; rev:5; metadata:created_at 2011_07_05, signature_severity Major, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2019_07_26;)