Description

Spring Security versions 5.1.x prior to 5.1.2 contain an authorization bypass vulnerability during JWT issuer validation. In order to be impacted, the same private key for an honest issuer and a malicious user must be used when signing JWTs. In that case, a malicious user could fashion signed JWTs with the malicious issuer URL that may be granted for the honest issuer.

Affected Spring Products and Versions

• Spring Framework 5.1 to 5.1.1

Mitigation

Users of affected versions should apply the following mitigation:

• 5.1.x users should upgrade to 5.1.2

There are no other mitigation steps necessary.

Credit

This issue was identified and responsibly reported by Björn Bilger.

References

• Example https://docs.spring.io/spring-security/site/docs/5.1.1.RELEASE/reference/htmlsingle/#oauth2resourceserver-minimalconfiguration'>config</a> where a simple Resource Server is enabled.
• https://docs.spring.io/spring-security/site/docs/5.1.1.RELEASE/reference/htmlsingle/#oauth2resourceserver'>Spring Security Resource Server Support documentation.

History

2018-12-18: Initial vulnerability report published.