alert http $EXTERNAL_NET any -> $HOME_NET any (msg:"ET WEB_SERVER c99 Shell Backdoor Var Override URI"; flow:to_server,established; http.uri; content:"c99shcook["; nocase; fast_pattern; pcre:"/[&?]c99shcook\[/i"; reference:url,thehackerblog.com/every-c99-php-shell-is-backdoored-aka-free-shells/; classtype:trojan-activity; sid:2018601; rev:4; metadata:created_at 2014_06_24, signature_severity Major, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2020_09_24;)