Improper Input Validation in cve-search Exposes MongoDB Data

Impact Analysis

The impact of this vulnerability is severe. An attacker can gain unauthorized access to sensitive administrative data, including password hashes.

With access to password hashes, attackers can perform offline password cracking to potentially recover administrative credentials.

This can lead to a full administrative takeover of the cve-search instance, compromising the integrity and confidentiality of the system.

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Executive Summary

This vulnerability is an unauthenticated improper input validation issue in the POST /fetch_cve_data endpoint of the cve-search application. It allows a remote attacker to manipulate request parameters that control the MongoDB collection, projected fields, and regular-expression filters. By doing so, the attacker can read arbitrary MongoDB collections within the application.

Specifically, this flaw enables attackers to access sensitive data such as administrative usernames and password hashes stored in the mgmt_users collection. This is possible because the endpoint does not validate or restrict the input parameters, allowing unauthorized access to data that should be protected.

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Detection Guidance

This vulnerability can be detected by monitoring for unusual or unauthorized POST requests to the /fetch_cve_data endpoint that include manipulated parameters such as collection names, projected fields, or regular-expression filters targeting MongoDB collections.

A practical detection method is to capture and analyze HTTP POST requests to /fetch_cve_data for suspicious payloads that attempt to access collections other than the expected CVE data.

Example commands to detect exploitation attempts include using curl to simulate or inspect requests, or using network monitoring tools like tcpdump or Wireshark to filter traffic:

• curl -X POST -H "Content-Type: application/json" -d '{"collection":"mgmt_users"}' http://<target>/fetch_cve_data
• tcpdump -A -s 0 'tcp port 80 and (((ip[2:2] - ((ip[0]&0xf)<<2)) - ((tcp[12]&0xf0)>>2)) != 0)' | grep '/fetch_cve_data'
• Use application logs to search for POST requests to /fetch_cve_data with parameters specifying collections other than CVE data.

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Mitigation Strategies

Immediate mitigation steps include applying the patch that enforces server-side validation on the /fetch_cve_data endpoint to restrict queries strictly to the CVE collection and expected schema fields.

Specifically, update the cve-search application to the fixed version where the endpoint rejects unauthorized collection access, validates DataTables column projections and sorting, and enforces pagination bounds, returning HTTP 400 errors for invalid requests.

Additionally, restrict network access to the vulnerable endpoint to trusted users only, and monitor logs for suspicious access attempts.

• Apply the patch from the pull request that introduces strict validation on /fetch_cve_data.
• Restrict access to the cve-search service via firewall or network controls.
• Monitor and audit logs for unusual POST requests targeting /fetch_cve_data.

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