Versions of loopback-connector-mongodb before 3.6.0 are vulnerable to NoSQL injection.

MongoDB Connector for LoopBack fails to properly sanitize a filter passed to query the database by allowing the dangerous $where property to be passed to the MongoDB Driver. The Driver allows the special $where property in a filter to execute JavaScript (client can pass in a malicious script) on the database Driver. This is an intended feature of MongoDB unless disabled (instructions here).

A proof of concept malicious query:

GET /POST filter={"where": {"$where": "function(){sleep(5000); return this.title.contains('Hello');}"}}

The above makes the database sleep for 5 seconds and then returns all “Posts” with the title containing the word Hello.

Recommendation

Update to version 3.6.0 or later.

References

• loopbackio/loopback-connector-mongodb#403
• loopbackio/loopback-connector-mongodb#452
• loopbackio/loopback-connector-mongodb@ee24cd0
• https://loopback.io/doc/en/lb3/Security-advisory-08-15-2018.html
• https://www.npmjs.com/advisories/696