CVE-2023-2253: Input Validation
Impact
Systems that run distribution built after a specific commit running on memory-restricted environments can suffer from denial of service by a crafted malicious /v2/catalog API endpoint request.
Patches
Upgrade to at least 2.8.2-beta.1 if you are running v2.8.x release. If you use the code from the main branch, update at least to the commit after f55a6552b006a381d9167e328808565dd2bf77dc.
Workarounds
There is no way to work around this issue without patching. Restrict access to the affected API endpoint: see the recommendations section.
References
/v2/catalog endpoint accepts a parameter to control the maximum amount of records returned (query string: n).
When not given the default n=100 is used. The server trusts that n has an acceptable value, however when using a maliciously large value, it allocates an array/slice of n of strings before filling the slice with data.
This behaviour was introduced ~7yrs ago [1].
Recommendation
The /v2/catalog endpoint was designed specifically to do registry syncs with search or other API systems. Such an endpoint would create a lot of load on the backend system, due to overfetch required to serve a request in certain implementations.
Because of this, we strongly recommend keeping this API endpoint behind heightened privilege and avoiding leaving it exposed to the internet.
For more information
If you have any questions or comments about this advisory: Open an issue in distribution repository Email us at cncf-distribution-security@lists.cncf.io
[1] faulty commit
Other sources
A flaw was found in the /v2/catalog endpoint in distribution/distribution, which accepts a parameter to control the maximum number of records returned (query string: n). This vulnerability allows a malicious user to submit an unreasonably large value for n, causing the allocation of a massive string array, possibly causing a denial of service through excessive use of memory.
— Ubuntu
Distribution is vulnerable to a denial of service, caused by improper input validation by the /v2/catalog endpoint. By sending a specially crafted /v2/catalog API endpoint request request, a remote attacker could exploit this vulnerability to cause a denial of service condition.
— IBM
The /v2/catalog endpoint in distribution/distribution accepts a parameter to control the maximum amount of records returned (query string: n). This allows a malicious user to submit a unreasonably large value for n, causing the allocation of a massive string array, possibly causing a DoS through excessive use of memory.
— Red Hat
Affected Software
Event History
Frequently Asked Questions
What is CVE-2023-2253?
CVE-2023-2253 is a vulnerability in the distribution/distribution software that allows a malicious user to cause a denial of service through improper input validation.
What is the severity of CVE-2023-2253?
CVE-2023-2253 has a severity rating of 7.5, which is considered high.
How does CVE-2023-2253 work?
CVE-2023-2253 works by accepting an unreasonably large value for the 'n' parameter in the '/v2/_catalog' endpoint, leading to the allocation of a massive amount of memory and causing a denial of service.
Is there a fix for CVE-2023-2253?
Yes, the vulnerability can be fixed by updating to version 2.8.2 or higher of the docker-registry package.
Where can I find more information about CVE-2023-2253?
More information about CVE-2023-2253 can be found at the following references: [CVE-2023-2253](https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2023-2253), [GitHub Commit](https://github.com/distribution/distribution/commit/521ea3d973cb0c7089ebbcdd4ccadc34be941f54), [Openwall Security Mailing List](https://www.openwall.com/lists/oss-security/2023/05/09/1).