alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"ET MALWARE DDoS.XOR Checkin 2"; flow:to_server,established; http.method; content:"GET"; http.uri; content:"/check?iid="; fast_pattern; content:"kernel="; distance:0; pcre:"/iid=[a-fA-F0-9]{32}&kernel=/"; reference:url,blog.avast.com/2015/01/06/linux-ddos-trojan-hiding-itself-with-an-embedded-rootkit/#more-33072; classtype:command-and-control; sid:2021334; rev:3; metadata:created_at 2015_06_24, signature_severity Major, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2020_05_28;)