alert dns $HOME_NET any -> any any (msg:"ET MALWARE Prometei Botnet CnC DGA - xinchao Pattern"; dns.query; content:"xinchao"; fast_pattern; startswith; pcre:"/^[a-f0-9]{6}/Ri"; bsize:>13; reference:url,blog.talosintelligence.com/prometei-botnet-improves/; classtype:trojan-activity; sid:2044560; rev:1; metadata:attack_target Client_Endpoint, created_at 2023_03_10, deployment Perimeter, malware_family prometei, performance_impact Low, confidence Medium, signature_severity Major, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2023_03_10, reviewed_at 2025_07_14;)