alert tcp $HOME_NET any -> $EXTERNAL_NET ![445,139] (msg:"ET MALWARE Backdoor.Win32.PcClient.bal CnC (OUTBOUND)"; flow:to_server,established; dsize:248; content:"|18 18|"; offset:2; depth:2; content:!"|18 18|"; within:2; content:"|18 18|"; distance:2; within:2; content:!"|18 18|"; within:2; content:"|18 18 18 18 18 18 18 18 18 18 18 18 18 18 18 18 18 18 18 18|"; pcre:"/[^\x18][^\x44\x32\x33\x25\x64\x22\x23\x3a\x27\x24\x26\x34\x3b\x12][\x20\x21\x28-\x2f\x70-\x77\x79-\x7f\x60-\x63\x65\x66\x67-\x6f\x50-\x5f\x40-\x42\x46-\x4f\x30\x31\x35\x36\x38\x3e\x39\x3b]{1,14}\x18/R"; reference:md5,16549f8a09fd5724f2107a8f18dca10b; classtype:command-and-control; sid:2019204; rev:11; metadata:created_at 2014_09_22, confidence High, signature_severity Major, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2021_08_02;)