CGA-jw9h-hmw7-8m6p

Summary

distribution catalog API endpoint can lead to OOM via malicious user input

Description

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