Potential Toolshell Initial Exploit (CVE-2025-53770 & CVE-2025-53771)

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Potential Toolshell Initial Exploit (CVE-2025-53770 & CVE-2025-53771)

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Identifies potential exploitation of CVE-2025-53770 and CVE-2025-53771 in IIS web servers on SharePoint sites. Toolshell is an exploit chain that leverages vulnerabilities in SharePoint/IIS to gain unauthorized access and execute commands. This rule detects HTTP requests that match specific patterns indicative of the exploit attempt.

Rule type: query

Rule indices:

  • logs-network_traffic.http*

Severity: low

Risk score: 21

Runs every: 60m

Searches indices from: now-119m (Date Math format, see also Additional look-back time)

Maximum alerts per execution: 100

References:

Tags:

  • Domain: Network
  • Tactic: Initial Access
  • Use Case: Exploit Detection
  • Data Source: Network Traffic
  • Data Source: Network Traffic HTTP Logs
  • Rule Type: BBR

Version: 1

Rule authors:

  • Elastic

Rule license: Elastic License v2

Setup

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Network Traffic Setup

This rule requires network traffic logs to be collected from HTTP endpoints, specifically focusing on IIS web servers. Ensure that your network traffic logging is configured to capture HTTP request and response details, including request and response headers. Additionally, request bodies are necessary for content-type application/x-www-form-urlencoded to detect potential exploit attempts.

Rule query

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data_stream.dataset : "network_traffic.http" and
    url.path: (/_layouts*ToolPane.aspx* or /_layouts*toolpane.aspx*) and
    http.request.referrer: *SignOut.aspx and
    network.direction: "ingress" and
    http.request.method: "POST" and
    request: (*MSOTlPn_Uri* and *DisplayMode*) and
    http.request.body.bytes >  2000

Framework: MITRE ATT&CKTM