Attack Chain

1. The attacker sends a crafted HTTP request to the spire-doc-mcp-server.
2. The request targets an endpoint that utilizes the vulnerable get_doc_path function.
3. The attacker manipulates the document_name parameter within the request.
4. The document_name parameter contains a path traversal sequence (e.g., “../”) designed to escape the intended directory.
5. The get_doc_path function fails to properly sanitize or validate the document_name input.
6. The application constructs a file path based on the malicious input.
7. The application attempts to read the file at the attacker-controlled path.
8. The attacker successfully retrieves the contents of an arbitrary file on the server.

Impact

Successful exploitation of this path traversal vulnerability allows an attacker to read sensitive files on the server. This could include configuration files containing credentials, source code, or other confidential data. The CVSS v3.1 score of 7.3 reflects the high severity of this issue. The lack of vendor response and availability of public exploits significantly increases the risk to organizations using vulnerable versions of spire-doc-mcp-server.

Recommendation

• Deploy the Sigma rule Detect Spire-doc-mcp-server Path Traversal Attempt to your SIEM to detect exploitation attempts by monitoring web server logs for path traversal sequences.
• Apply input validation and sanitization to the document_name argument in the get_doc_path function within src/spire_doc_mcp/api/base.py to prevent path traversal.
• Monitor web server logs for HTTP requests containing path traversal sequences (e.g., “..%2F”, “../”) targeting endpoints related to document retrieval.