alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"ET MALWARE Backdoor.Win32.Pushdo.s Checkin"; flow:to_server,established; urilen:39; http.method; content:"POST"; http.uri; content:"/?ptrxcz_"; fast_pattern; pcre:"/^\/\?ptrxcz_[a-z0-9A-Z]{30}$/"; reference:md5,58ffe2b79be4e789be80f92b7f96e20c; classtype:command-and-control; sid:2015807; rev:5; metadata:created_at 2012_10_05, signature_severity Major, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2020_09_17;)