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Security Advisories: GSA_kwCzR0hTQS1qcmYyLWg1ajYtM3Jycc4AA2kC

Bunkum tokens cached in the AuthenticationService are susceptible to a use-after-free

Impact

First, a little bit of background. So, in the beginning, Bunkum's AuthenticationService only supported injecting IUsers. However, as Refresh and SoundShapesServer implemented permissions systems support for injecting ITokens into endpoints was added. All was well until 4.0.

Bunkum 4.0 then changed to enforce relations between ITokens and IUsers. This wasn't implemented in a very good way in the AuthenticationService, and ended up breaking caching in such a way that cached tokens would persist after the lifetime of the request - since we tried to cache both tokens and users. From that point until now, from what I understand, Bunkum was attempting to use that cached token at the start of the next request once cached.

Naturally, when that token expired, downstream projects like Refresh would remove the object from Realm - and cause the object in the cache to be in a detached state, causing an exception from invalid use of IToken.User. So in other words, a use-after-free since Realm can't manage the lifetime of the cached token.

Security-wise, the scope is fairly limited, can only be pulled off on a couple endpoints given a few conditions, and you can't guarantee which token you're going to get. Also, the token would get invalidated properly if the endpoint had either a IToken usage or a IUser usage. User interaction is required as authenticated requests must be performed.

Patches

The fix is to just wipe the token cache after the request was handled, which is now in 4.2.1. I'd recommend that you update. Unfortunately, there are no real workarounds for other versions in the 4.X.X range.

Permalink: https://github.com/advisories/GHSA-jrf2-h5j6-3rrq
JSON: https://advisories.ecosyste.ms/api/v1/advisories/GSA_kwCzR0hTQS1qcmYyLWg1ajYtM3Jycc4AA2kC
Source: GitHub Advisory Database
Origin: Unspecified
Severity: Moderate
Classification: General
Published: about 1 year ago
Updated: about 1 year ago


CVSS Score: 5.3
CVSS vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N

Identifiers: GHSA-jrf2-h5j6-3rrq, CVE-2023-45814
References: Repository: https://github.com/LittleBigRefresh/Bunkum
Blast Radius: 1.0

Affected Packages

nuget:Bunkum
Dependent packages: 10
Dependent repositories: 0
Downloads: 41,559 total
Affected Version Ranges: >= 4.0.0, < 4.2.1
Fixed in: 4.2.1
All affected versions: 4.0.0, 4.0.1, 4.1.0, 4.2.0
All unaffected versions: 1.0.0, 1.0.1, 1.0.2, 1.0.3, 1.0.4, 1.0.5, 1.0.6, 1.0.7, 2.0.0, 2.0.1, 2.0.2, 2.0.3, 2.0.4, 2.1.0, 2.1.1, 2.1.2, 2.1.3, 2.1.4, 2.1.5, 2.2.0, 2.2.1, 2.2.2, 2.2.3, 2.2.4, 2.2.5, 2.2.6, 2.2.7, 2.2.8, 2.2.9, 2.2.10, 2.2.11, 2.2.12, 2.3.0, 2.3.1, 3.0.0, 3.0.1, 3.0.2, 3.0.3, 3.0.4, 3.0.5, 3.0.6, 3.1.0, 3.1.1, 3.1.2, 3.1.3, 3.1.4, 3.1.5, 3.2.0, 3.2.1, 3.2.2, 3.2.3, 3.3.0, 3.3.1, 3.3.2, 3.3.3, 3.3.4, 3.3.5, 3.3.6, 3.3.7, 3.3.8, 3.3.9, 3.3.10, 3.3.11, 3.3.12, 3.3.13, 3.3.14, 3.3.15, 3.3.16, 3.3.17, 3.3.18, 3.4.0, 3.4.1, 3.4.2, 3.4.3, 3.4.4, 3.4.5, 3.5.0, 4.2.1, 4.2.2, 4.2.3, 4.3.0, 4.3.1, 4.3.2, 4.3.3, 4.4.0, 4.4.1, 4.4.2, 4.4.3, 4.4.4, 4.4.5, 4.5.0, 4.5.1, 4.5.2, 4.5.3, 4.5.4, 4.5.5, 4.5.6, 4.6.0, 4.7.0, 4.7.1, 4.8.0, 4.8.1