alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"ET MALWARE W32/Einstein CnC Checkin"; flow:established,to_server; content:"POST"; nocase; http_method; content:".php?id="; http_uri; content:"&ext="; http_uri; pcre:"/\x2F[a-z]{5}\x2Ephp\x3Fid\x3D/U"; reference:url,www.cyberesi.com/2011/10/06/trojan-matryoshka-and-trojan-einstein/; classtype:command-and-control; sid:2013767; rev:3; metadata:created_at 2011_10_12, signature_severity Major, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2019_07_26;)