ET MALWARE [Fireeye] Observed SUNBURST DGA Request

alert dns $HOME_NET any -> any any (
    msg:"ET MALWARE [Fireeye] Observed SUNBURST DGA Request";
    dns.query;
    content:".appsync-api."; nocase;
    content:".avsvmcloud.com"; distance:9; within:15; endswith; nocase; fast_pattern;
    pcre:"/^[a-z0-9]+\.appsync-api\.(?:eu|us)-(?:ea|we)st-[12]\.avsvmcloud\.com$/";
    reference:url,www.fireeye.com/blog/threat-research/2020/12/evasive-attacker-leverages-solarwinds-supply-chain-compromises-with-sunburst-backdoor.html;
    classtype:trojan-activity;
    sid:2031359; rev:3;
    metadata:attack_target Client_Endpoint, created_at 2020_12_14, deployment Perimeter, deployment Internal, confidence High, signature_severity Major, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2020_12_16;
)