hey @kevross33, thanks for the rule submission! Here is the final rule that went out in today’s release. 
alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"ET MALWARE Turla APT/Kazuar Backdoor CnC Activity (POST)"; flow:established,to_server; http.method; content:"POST"; http.uri; content:".php"; endswith; http.cookie; content:"AspNet.Cookies=MTY5NzM5ZTcyMTEyOTUxNDZhNjFkMzAwYzBmZWYwMmQ="; bsize:59; fast_pattern; http.request_body; content:"|3c|"; depth:1; content:"|3e 3c|"; reference:url,community.emergingthreats.net/t/new-sig-et-trojan-w32-kazuar-backdoor-turla-apt-hardcoded-cookie/1136; reference:url,unit42.paloaltonetworks.com/pensive-ursa-uses-upgraded-kazuar-backdoor; classtype:trojan-activity; sid:2049264;)