alert tcp $HOME_NET any -> $EXTERNAL_NET any (msg:"ET MALWARE Win32/Spy.Agent.OHT - AnunakAPT TCP Checkin 1"; flow:established,to_server; dsize:24; content:"|08 00 1b 00 00 00 1b 00 00 00 02 00 00 00 00 00 00 00 00 00|"; fast_pattern; content:"|00 00 00 00 |"; offset:20; depth:4; reference:url,fox-it.com/en/files/2014/12/Anunak_APT-against-financial-institutions2.pdf; classtype:targeted-activity; sid:2020024; rev:3; metadata:created_at 2014_12_23, malware_family Win32_Spy_Agent_OHT, confidence High, signature_severity Major, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2019_10_08;)