ET WEB_SPECIFIC_APPS Microsoft Sharepoint WebPartPages Authenticated Remote Code Execution (CVE-2021-28474)

alert http any any -> $HOME_NET any (
    msg:"ET WEB_SPECIFIC_APPS Microsoft Sharepoint WebPartPages Authenticated Remote Code Execution (CVE-2021-28474)";
    flow:established,to_server;
    http.method;
    content:"POST";
    http.uri;
    content:"/_vti_bin/WebPartPages.asmx"; fast_pattern;
    http.request_body;
    pcre:"/[rR][uU][nN][aA][tT](?:\x3d|\x253[dD]|\x26equals\x3b)(?:\x22|\x2522|\x26quot\x3b)server(?:\x22|\x2522|\x26quot\x3b)/";
    content:"OuterHtml|3d|";
    content:"|2f|web.config"; distance:0;
    reference:url,www.zerodayinitiative.com/blog/2021/7/7/cve-2021-28474-sharepoint-remote-code-execution-via-server-side-control-interpretation-conflict;
    reference:cve,2021-28474;
    classtype:web-application-attack;
    sid:2063645; rev:2;
    metadata:affected_product Microsoft_Sharepoint, attack_target Server, tls_state TLSDecrypt, created_at 2025_07_21, cve CVE_2021_28474, deployment Perimeter, deployment Internal, confidence High, signature_severity Major, tag Exploit, updated_at 2025_07_22, mitre_tactic_id TA0001, mitre_tactic_name Initial_Access, mitre_technique_id T1190, mitre_technique_name Exploit_Public_Facing_Application;
    target:dest_ip;
)