alert tcp $HOME_NET any -> $EXTERNAL_NET any (msg:"ET MALWARE x0Proto Pong"; flow:established,to_server; flowbits:isset,et.x0proto; dsize:9; content:"x53|0c|"; depth:4; content:"|0c|0|0c|1"; distance:1; within:4; classtype:trojan-activity; sid:2012238; rev:2; metadata:created_at 2011_01_27, signature_severity Major, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2019_07_26;)