Google OAuth client library for Java was found vulnerable by a PH.D. student of Computer Science at the University of Virginia in the middle of March this year. Google has awarded the student named Tamjid Al Rahat with $5,000 within the scope of the company’s bug bounty program.
The bug had a high severity rating
The vulnerability on the Google OAuth client library for Java can be tracked as CVE-2021-22573 and has a severity score of 8.7. It allows users to bypass authentication in the library, thanks to the bug causing improper verification of the cryptographic signature. By achieving this, the attackers would be able to deploy arbitrary payloads to the target systems.
« The vulnerability is that the IDToken verifier does not verify if the token is properly signed. Signature verification makes sure that the token’s payload comes from a valid provider, not from someone else. An attacker can provide a compromised token with a custom payload. The token will pass the validation on the client-side »
Google has updated the google-oauth-java-client library to the 1.33.3 version to fix the issue. The company recommends updating the aforementioned version to mitigate the potential security issues.