Overview
This is the initial Apereo CAS project vulnerability disclosure, describing an issue in CAS acting as an OAuth/OpenID Connect provider. If your CAS server is not acting as an OAuth/OpenID Connect provider producing claims and attributes, there is nothing for you to do here. Keep calm and carry on.
For additional details on how security issues, patches and announcements are handled, please read the Apereo CAS project vulnerability disclosure process.
Credits
This issue was originally reported, researched and tested by Mr. Terry Appleby, who is a senior developer at wicket.io Terry was kind enough to thoroughly investigate the issue, discuss the problem in detail, provide steps to reproduce the problem with an actual CAS overlay and puppeteer test and offer insight to diagnose the root cause.
Thank you!
Affected Deployments
The problem addressed here, per the CAS maintenance policy, affects the Apereo CAS server for the following versions:
- 6.5.x
- 6.6.x
If your CAS version is not listed above AND is still part of an active maintenance cycle per the CAS maintenance policy, then best effort (analysis or confirmation from reporters/testers) indicates that the version is not affected by this issue. That said, please note that per the project’s Apache2 license, software distributed under the License is distributed on an “AS IS” BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. For additional information, please see the project license.
If you or your institution is a member of the Apereo foundation with an active support subscription supporting the CAS project, please contact the CAS subs working group to learn more about this security vulnerability report.
Severity
This is the initial version of an Apereo CAS project vulnerability disclosure. This post will be updated once the security grace period has passed.
Timeline
The issue was originally reported on September 13th, 2023 and upon confirmation, CAS releases were patched and published on September 14th, 2023.
Patching
Patch releases are available to address CAS deployments. Upgrades to the next patch version for each release should be a drop-in replacement.
Procedure
This is the initial version of an Apereo CAS project vulnerability disclosure. All source code and repository tags that contain fixes for this issue are kept privately until the grace period has passed. Note that repository tags are generally irrelevant when it comes to applying fixes described below, unless you intend to build the CAS codebase from source and a tagged commit instead of relying on a binary published release.
6.5.x
Modify your CAS overlay to point to the version 6.5.9.4.
6.6.x
Modify your CAS overlay to point to the version 6.6.12.
Support
Apereo CAS is Apache v2 open source software under the sponsorship of the Apereo Foundation, supported by community volunteers and enthusiasts. Support options may be found here.
If you or your institution is a member of the Apereo foundation with an active subscription supporting the CAS project, please contact the CAS subs working group to learn more about this security vulnerability report.
Resources
On behalf of the CAS Application Security working group,