Vulnerability roundup 112: cosign-1.3.0: 1 advisory [3.3]

[ckauhaus]

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• CVE-2022-23649 CVSSv3=3.3 (nixos-21.11)

CVE details

CVE-2022-23649

Cosign provides container signing, verification, and storage in an OCI registry for the sigstore project. Prior to version 1.5.2, Cosign can be manipulated to claim that an entry for a signature exists in the Rekor transparency log even if it doesn't. This requires the attacker to have pull and push permissions for the signature in OCI. This can happen with both standard signing with a keypair and "keyless signing" with Fulcio. If an attacker has access to the signature in OCI, they can manipulate cosign into believing the entry was stored in Rekor even though it wasn't. The vulnerability has been patched in v1.5.2 of Cosign. The signature in the signedEntryTimestamp provided by Rekor is now compared to the signature that is being verified. If these don't match, then an error is returned. If a valid bundle is copied to a different signature, verification should fail. Cosign output now only informs the user that certificates were verified if a certificate was in fact verified. There is currently no known workaround.

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Scanned versions: nixos-21.11: efea022.

Cc @06kellyjac
Cc @LeSuisse
Cc @kalbasit

[06kellyjac]

There are breaking changes between 1.3.0 and 1.6.0

What is the stance on fixing vulns vs keeping 21.11 stable?

[LeSuisse]

Also, I tried to backport only the fix but it is not straightforward. I did not feel comfortable moving forward with a heavily customized patch since it could lead to more serious issues than the existing one.

[mweinelt]

With the precondition being push/pull permissions on the container infrastructure and the resulting low CVSSv3 score of 3.3 I think it's okay to ignore this for release-21.11 if it is problematic to backport in a non-breaking way.

[ckauhaus]

I'd also opt for leaving 21.11 as is.