alert tcp $HOME_NET any -> $EXTERNAL_NET [443,$HTTP_PORTS] (msg:"ET MALWARE Pushdo v3 Checkin"; flow:established,to_server; dsize:20; content:"|02 00 00 00|"; depth:4; reference:md5,776d6c20a7016cb0f0db354785fe0d71; classtype:command-and-control; sid:2019235; rev:1; metadata:created_at 2014_09_25, signature_severity Major, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2019_07_26;)