The identity service in OpenStack Identity (Keystone) before 2015.1.3 (Kilo) and 8.0.x before 8.0.2 (Liberty) and keystonemiddleware (formerly python-keystoneclient) before 1.5.4 (Kilo) and Liberty before 2.3.3 does not properly invalidate authorization tokens when using the PKI or PKIZ token providers, which allows remote authenticated users to bypass intended access restrictions and gain access to cloud resources by manipulating byte fields within a revoked token.

A vulnerability was discovered in OpenStack:

Title: S3Token TLS cert verification option not honored Reporter: Brant Knudson (IBM) Products: keystonemiddleware, python-keystoneclient Affects: versions up to 1.5.0 (keystonemiddleware), versions up to 0.11.2 (python-keystoneclient)

Description: Brant Knudson from IBM reported a vulnerability in keystonemiddleware (formerly shipped as python-keystoneclient). When the 'insecure' option is set in a S3Token paste configuration file its value is effectively ignored and instead assumed to be true. As a result certificate verification will be disabled, leaving TLS connections open to MITM attacks. Note that it's unusual to explicitly add this option and then set it to false, so the impact of this bug is thought to be limited. All versions of s3token middleware with TLS settings configured are affected by this flaw.

Acknowledgements:

Red Hat would like to thank the OpenStack project for reporting this issue. Upstream acknowledges Brant Knudson from IBM as the original reporter.