GHSA-cq38-jh5f-37mq

Source

https://github.com/advisories/GHSA-cq38-jh5f-37mq

Import Source

https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2024/09/GHSA-cq38-jh5f-37mq/GHSA-cq38-jh5f-37mq.json

JSON Data

https://api.osv.dev/v1/vulns/GHSA-cq38-jh5f-37mq

Aliases

Related

Published

2024-09-04T20:18:18Z

Modified

2024-09-06T21:27:04.439052Z

Severity

3.1 (Low) CVSS_V3 - CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:N/I:N/A:L CVSS Calculator
2.3 (Low) CVSS_V4 - CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:P/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N CVSS Calculator

Summary

sigstore-go has an unbounded loop over untrusted input can lead to endless data attack

Details

Impact

sigstore-go is susceptible to a denial of service attack when a verifier is provided a maliciously crafted Sigstore Bundle containing large amounts of verifiable data, in the form of signed transparency log entries, RFC 3161 timestamps, and attestation subjects. The verification of these data structures is computationally expensive. This can be used to consume excessive CPU resources, leading to a denial of service attack. TUF's security model labels this type of vulnerability an "Endless data attack," and can lead to verification failing to complete and disrupting services that rely on sigstore-go for verification.

The vulnerable loops are in the verification functions in the package github.com/sigstore/sigstore-go/pkg/verify. The first is the DSSE envelope verification loop in verifyEnvelopeWithArtifact, which decodes all the digests in an attestation can be found here:

https://github.com/sigstore/sigstore-go/blob/725e508ed4933e6f5b5206e32af4bbe76f587b54/pkg/verify/signature.go#L183-L193

The next loop is in the VerifyArtifactTransparencyLog function, which verifies all the signed entries in a bundle:

https://github.com/sigstore/sigstore-go/blob/725e508ed4933e6f5b5206e32af4bbe76f587b54/pkg/verify/tlog.go#L74-L178

The next loop is the VerifyTimestampAuthority function, which verifies all the RFC 3161 timestamps in a bundle:

https://github.com/sigstore/sigstore-go/blob/725e508ed4933e6f5b5206e32af4bbe76f587b54/pkg/verify/tsa.go#L59-L68

Patches

This vulnerability is addressed with sigstore-go 0.6.1, which adds hard limits to the number of verifiable data structures that can be processed in a bundle. Verification will fail if a bundle has data that exceeds these limits. The limits are:

32 signed transparency log entries
32 RFC 3161 timestamps
1024 attestation subjects
32 digests per attestation subject

These limits are intended to be high enough to accommodate the vast majority of use cases, while preventing the verification of maliciously crafted bundles that contain large amounts of verifiable data.

Workarounds

The best way to mitigate the risk is to upgrade to sigstore-go 0.6.1 or later. Users who are vulnerable but unable to quickly upgrade may consider adding manual bundle validation to enforce limits similar to those in the referenced patch prior to calling sigstore-go's verification functions.

Database specific

{
    "nvd_published_at": "2024-09-04T21:15:14Z",
    "cwe_ids": [
        "CWE-835"
    ],
    "severity": "LOW",
    "github_reviewed": true,
    "github_reviewed_at": "2024-09-04T20:18:18Z"
}

References

Affected packages

Go / github.com/sigstore/sigstore-go

Package

Name: github.com/sigstore/sigstore-go; View open source insights on deps.dev
Purl: pkg:golang/github.com/sigstore/sigstore-go

Affected ranges

Type: SEMVER
Events: Introduced

0Unknown introduced version / All previous versions are affected

Fixed

0.6.1

Database specific

{
    "last_known_affected_version_range": "<= 0.6.0"
}