ET WEB_SPECIFIC_APPS Microsoft SharePoint Authenticated Remote Code Execution via Insecure Deserialization (CVE-2026-45659)

alert http any any -> [$HOME_NET,$HTTP_SERVERS] any (
    msg:"ET WEB_SPECIFIC_APPS Microsoft SharePoint Authenticated Remote Code Execution via Insecure Deserialization (CVE-2026-45659)";
    flow:established,to_server;
    http.uri;
    content:"/_api/web/lists/getbytitle"; fast_pattern; startswith;
    content:"/items"; distance:0;
    http.request_body; strip_whitespace;
    content:"|22|SP.Data.ListItem|22|";
    content:"|22|Value|22 3a 22|";
    pcre:"/^[^\x22]*?(?:U3lzdGVtLkRpYWdub3N0aWNzLlByb2Nlc3NTdGFydEluZm|N5c3RlbS5EaWFnbm9zdGljcy5Qcm9jZXNzU3RhcnRJbmZv|TeXN0ZW0uRGlhZ25vc3RpY3MuUHJvY2Vzc1N0YXJ0SW5mb)/R";
    http.method;
    content:"POST";
    reference:url,github.com/HORKimhab/CVE-2026-45659;
    reference:cve,2026-45659;
    classtype:web-application-attack;
    sid:2071422; rev:1;
    metadata:affected_product Microsoft_Sharepoint, attack_target Server, tls_state TLSDecrypt, created_at 2026_08_07, cve CVE_2026_45659, deployment Perimeter, deployment Internal, deployment SSLDecrypt, confidence High, signature_severity Major, tag Exploit, updated_at 2026_08_07, mitre_tactic_id TA0001, mitre_tactic_name Initial_Access, mitre_technique_id T1190, mitre_technique_name Exploit_Public_Facing_Application;
    target:dest_ip;
)