alert tcp $HOME_NET any -> $EXTERNAL_NET 80 (msg:"ET MALWARE Win32/Kelihos.F Checkin"; flow:to_server,established; dsize:164; content:"|6c 55 55 45 03 10 48 40|"; offset:4; depth:8; reference:md5,dc226166dfbe28eee2576ea5141bc19d; reference:md5,dadee91e0b82fc91a25a66b61bb2f2dc; classtype:command-and-control; sid:2021947; rev:3; metadata:created_at 2015_10_13, malware_family Win32_Kelihos_F, confidence Medium, signature_severity Major, updated_at 2019_07_26;)