alert dns $HOME_NET any -> any any (msg:"ET MALWARE Anchor_DNS Trickbot DNS CnC Command - Prepare to Receive Data"; content:"|00 00 00 00 00 00 2a 38 38|"; fast_pattern; dns.query; content:"88"; depth:2; content:"B9."; nocase; distance:38; within:3; pcre:"/^88[a-fA-F0-9]{38}b9\./i"; reference:url,technical.nttsecurity.com/post/102fsp2/trickbot-variant-anchor-dns-communicating-over-dns; classtype:command-and-control; sid:2028881; rev:2; metadata:affected_product Windows_XP_Vista_7_8_10_Server_32_64_Bit, attack_target Client_Endpoint, created_at 2019_10_21, deployment Perimeter, malware_family TrickBot, confidence Medium, signature_severity Major, tag Trickbot, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2020_04_15;)