alert dns $HOME_NET any -> any any (msg:"ET MALWARE APT DNSpionage/Karkoff CnC Domain in DNS Lookup"; dns.query; content:"kuternull.com"; nocase; endswith; reference:url,blog.talosintelligence.com/2019/04/dnspionage-brings-out-karkoff.html; classtype:targeted-activity; sid:2027281; rev:3; metadata:affected_product Windows_XP_Vista_7_8_10_Server_32_64_Bit, created_at 2019_04_24, deployment Perimeter, malware_family Karkoff, performance_impact Low, confidence High, signature_severity Major, tag APT34, updated_at 2020_09_17;)