MongoBleed (CVE-2025-14847)

Summary

MongoBleed (CVE-2025-14847) is a memory disclosure flaw in MongoDB’s zlib decompression that can allow unauthenticated attackers to leak sensitive data from server memory. It affects multiple MongoDB releases and may be triggered by opening thousands of rapid connections while omitting client metadata. Detection is difficult because the activity is largely visible only in MongoDB server logs. To help hunt for this pattern, the author provides a Velociraptor artifact.

Investigation

The Velociraptor artifact parses JSON-formatted MongoDB logs for connection (event 22943), metadata (event 51800), and disconnection (event 22944) events. It aggregates connections by source IP, calculates connection velocity and metadata rate, and assigns risk scores. Lab testing against vulnerable MongoDB containers showed the artifact flags high-velocity, low-metadata traffic consistent with MongoBleed exploitation attempts.

Mitigation

Apply MongoDB’s official patches (8.2.3, 8.0.17, 7.0.28, 6.0.27) to remediate the issue. Enable log retention and JSON logging so evidence is available for analysis. Deploy the Velociraptor detection artifact to monitor abnormal connection behavior and tune thresholds to reduce false positives.

Response

If a high-risk indicator is triggered, isolate the affected MongoDB instance, validate whether exploitation occurred, and collect logs and memory for forensics. Rotate any potentially exposed credentials or tokens and remediate impacted services. Continue monitoring for repeat activity, confirm all deployments are patched, and disable compression where it is not required.