ET WEB_SPECIFIC_APPS Kaseya VSA Unauthenticated XML External Entity Injection (CVE-2021-30201)

alert http any any -> [$HOME_NET,$HTTP_SERVERS] any (
    msg:"ET WEB_SPECIFIC_APPS Kaseya VSA Unauthenticated XML External Entity Injection (CVE-2021-30201)";
    flow:established,to_server;
    http.uri;
    content:"/vsaWS/KaseyaWS.asmx"; fast_pattern;
    http.request_body;
    content:"<soapenv:Envelope"; startswith;
    content:"|3c 21 5b|CDATA";
    http.method;
    content:"POST";
    reference:url,csirt.divd.nl/cves/CVE-2021-30201/;
    reference:cve,2021-30201;
    classtype:web-application-attack;
    sid:2069327; rev:1;
    metadata:affected_product Kaseya_VSA, attack_target Server, tls_state TLSDecrypt, created_at 2026_05_18, cve CVE_2021_30201, deployment Perimeter, deployment Internal, deployment SSLDecrypt, confidence High, signature_severity Major, tag Exploit, updated_at 2026_05_18, mitre_tactic_id TA0001, mitre_tactic_name Initial_Access, mitre_technique_id T1190, mitre_technique_name Exploit_Public_Facing_Application;
    target:dest_ip;
)