NoSQL Injection in loopback-connector-mongodb

Summary

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](https://docs.mongodb.com/manual/core/server-side-javascript/) unless disabled ([instructions here](https://docs.mongodb.com/manual/core/server-side-javascript/#disable-server-side-js)). 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.