alert tcp $EXTERNAL_NET $HTTP_PORTS -> $HOME_NET any (msg:"ET MALWARE Socks666 Checkin Success Packet"; flowbits:isset,BS.BPcheckin1; flow:established,from_server; dsize:4; content:"|9a 02 05 00|"; offset:0; depth:4; classtype:command-and-control; sid:2006399; rev:5; metadata:created_at 2010_07_30, signature_severity Major, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2019_07_26;)