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Hop-by-hop abuse to malform header mutatorGHSA-w9mr-28mw-j8hg

GHSA-w9mr-28mw-j8hg is a security vulnerability in github.com/ory/oathkeeper. A fix is available for github.com/ory/oathkeeper — see the affected versions and patch details below.

Also known asGO-2023-1747
Published
Updated
Affected
1 pkg
Patched
1 / 1
Exploits
None indexed
Exploitation data as of Aug 20, 2024 · OSV.dev, FIRST.org (EPSS)

Real-World Exposure

1 pkg affected
🐹github.com/ory/oathkeeper

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects Go packages — download data is not available via public APIs for these ecosystems.

Description

Impact

Downstream services relying on the presence of headers set by the header mutator could be exploited. A client can drop the header set by the header mutator by including that header's name in the Connection header. Example minimal config:

- id: 'example'
  upstream:
    url: 'https://example.com'
  match:
    url: 'http://127.0.0.1:4455/'
    methods:
      - GET
  authenticators:
    - handler: anonymous
  authorizer:
    handler: allow
  mutators:
    - handler: header
      config:
        headers:
          X-Subject: {{ .Subject }}

curl -H "Connection: close,x-subject" http://127.0.0.1:4455/

The X-Subject header will not arrive at the downstream server. It is completely dropped. In case the downstream server handles such a request in an unexpected way, an attacker can exploit this, assuming they know or guess the internal header name.

Patches

c5cc7f736dc84185034be4356057d1c7a656d797

Workarounds

The downstream server should handle the case that an expected header is not set by responding with an appropriate error.

References

See background info in https://github.com/golang/go/issues/50580

Affected Packages

1 total 1 fixed
EcosystemPackageVulnerable rangeFix
🐹Gogithub.com/ory/oathkeeperall versions0.40.3go get github.com/ory/oathkeeper@v0.40.3

Detection & mitigation playbook

Open-source dependency

  1. Detect

    Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for github.com/ory/oathkeeper, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

  2. Fix

    Update github.com/ory/oathkeeper to 0.40.3 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-w9mr-28mw-j8hg is resolved across your whole dependency graph.

  3. Workarounds

    If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

Frequently Asked Questions

### Impact Downstream services relying on the presence of headers set by the `header` mutator could be exploited. A client can drop the header set by the `header` mutator by including that header's name in the `Connection` header. Example minimal config: ```yaml - id: 'example' upstream: url: 'https://example.com' match: url: 'http://127.0.0.1:4455/' methods: - GET authenticators: - handler: anonymous authorizer: handler: allow mutators: - handler: header config: headers: X-Subject: {{ .Subject }} ``` ``` curl -H "Connection: c
O3 Security · Impact-Aware SCA

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Hop-by-hop abuse to malform header mutator