Algolia API Misconfiguration

Discovery

I was looking at a rather static site and wanted to search for something. This was when I noticed a search function powered by Algolia being present:

Algolia is a third-party, search as a service platform.

Site Search & Discovery powered by AIAlgolia

I found it rather odd that this site had this in use, so I looked into it out of curiosity. Further enumeration using browser inspector tools shows that each keystroke typed in the search bar sent a request to an external domain.

The external domain was https://APPID-dsn.algolia.net, and it included 2 parameters, namely the x-algolia-api-key and x-algolia-application-id.

The next question was whether this api-key parameter was meant to be exposed, so I read up on the Algolia documentation. It states that the keys are safe to expose provided they are set to SEARCH-ONLY. There is another Admin API key which must be kept secret.

API keys | AlgoliaAlgolia Documentation

I wanted to check the permissions of this key. Visiting https://APPID-dsn.algolia.net/1/keys/APIKEY?x-algolia-application-id=APPID&x-algolia-api-key=APIKEY will return the permissions of the key. The output from curl confirmed that excessive permissions were granted for this publicly exposed API key, and that it was the Admin key.

These administrative permissions are dangerous and can be abused by attackers:

• listIndexes can cause information disclosure.

• editSettings can be used to update indexes with Javascript, allowing for Stored XSS.

• addObject allows for indexes to be added, allowing attackers to deface the website by adding their own objects.

Fix and Cause

I worked with the developers to fix this issue, which included setting up my own Algolia instance. The dashboard allows for Admin API keys to be revoked and regenerated.

The fix was straightforward, revoke the admin key, and replace the old key with the Search-Only key. The real question is: How did this bug occur?

The root cause is their documentation. Algolia has 'dynamic' documentation, which generates code snippets for any developer to copy and paste, like so:

I found that this feature automatically includes the Admin API key. There is little prior warning about this, and the developer probably copied and pasted without knowing this. The API key shown above is for my now deleted Algolia account.

In hindsight, this is a major design flaw on Algolia's side.

Other Resources

Week 14 - Algolia API KeysWeb Hacking Tips

Algolia MisconfigurationSecjuice