GHSA-QVP4-RPMR-XWRR
Vulnerability from github – Published: 2021-06-23 18:00 – Updated: 2021-06-22 20:50Impact
When you make a request to an endpoint that requires the scope foo using an access token granted with that foo scope, introspection will be valid and that token will be cached. The problem comes when a second requests to an endpoint that requires the scope bar is made before the cache has expired. Whether the token is granted or not to the bar scope, introspection will be valid.
Patches
A patch will be released with v0.38.12-beta.1.
Workarounds
Per default, caching is disabled for the oauth2_introspection authenticator. When caching is disabled, this vulnerability does not exist.
Trace
The cache is checked in func (a *AuthenticatorOAuth2Introspection) Authenticate(...). From tokenFromCache() it seems that it only validates the token expiration date, but ignores whether the token has or not the proper scopes.
Post-Mortem
The vulnerability was introduced in PR #424. During review, we failed to require appropriate test coverage by the submitter which is the primary reason that the vulnerability passed the review process.
To avoid this from happening again we enabled codecov with a strict policy on the Ory Oathkeeper repository: Without an increase in code coverage the PR can not be merged.
To address this issue and any regressions we have added a test suite ensuring that the cache behaviour is correct in the different scenarios:
- Scope strategy is
none, cache is enabled, andrequested_scopeis not empty -> cache will not be used; - Scope strategy is
none, cache is enabled, andrequested_scopeis empty -> cache will be used; - Scope strategy is not
none, cache is enabled, andrequested_scopeis not empty -> cache will be used;
as well as validating if iss, aud, exp, token_use, and scope are validated.
Additionally, we added CodeQL scanning to the CI.
{
"affected": [
{
"database_specific": {
"last_known_affected_version_range": "\u003c= 0.38.11-beta.1"
},
"package": {
"ecosystem": "Go",
"name": "github.com/ory/oathkeeper"
},
"ranges": [
{
"events": [
{
"introduced": "0.38.0-beta.2"
},
{
"fixed": "0.38.12-beta.1"
}
],
"type": "ECOSYSTEM"
}
]
}
],
"aliases": [],
"database_specific": {
"cwe_ids": [
"CWE-863"
],
"github_reviewed": true,
"github_reviewed_at": "2021-06-22T20:50:44Z",
"nvd_published_at": null,
"severity": "HIGH"
},
"details": "### Impact\n\nWhen you make a request to an endpoint that requires the scope `foo` using an access token granted with that `foo` scope, introspection will be valid and that token will be cached. The problem comes when a second requests to an endpoint that requires the scope `bar` is made before the cache has expired. Whether the token is granted or not to the `bar` scope, introspection will be valid.\n\n### Patches\n\nA patch will be released with `v0.38.12-beta.1`.\n\n### Workarounds\n\nPer default, caching is disabled for the `oauth2_introspection` authenticator. When caching is disabled, this vulnerability does not exist.\n\n### Trace\n\nThe cache is checked in [`func (a *AuthenticatorOAuth2Introspection) Authenticate(...)`](https://github.com/ory/oathkeeper/blob/6a31df1c3779425e05db1c2a381166b087cb29a4/pipeline/authn/authenticator_oauth2_introspection.go#L152). From [`tokenFromCache()`](https://github.com/ory/oathkeeper/blob/6a31df1c3779425e05db1c2a381166b087cb29a4/pipeline/authn/authenticator_oauth2_introspection.go#L97) it seems that it only validates the token expiration date, but ignores whether the token has or not the proper scopes.\n\n### Post-Mortem\n\nThe vulnerability was introduced in PR #424. During review, we failed to require appropriate test coverage by the submitter which is the primary reason that the vulnerability passed the review process.\n\nTo avoid this from happening again we enabled codecov with a strict policy on the Ory Oathkeeper repository: Without an increase in code coverage the PR can not be merged.\n\nTo address this issue and any regressions we have added a test suite ensuring that the cache behaviour is correct in the different scenarios:\n\n- Scope strategy is `none`, cache is enabled, and `requested_scope` is not empty -\u003e cache will not be used;\n- Scope strategy is `none`, cache is enabled, and `requested_scope` is empty -\u003e cache will be used;\n- Scope strategy is not `none`, cache is enabled, and `requested_scope` is not empty -\u003e cache will be used;\n\nas well as validating if `iss`, `aud`, `exp`, `token_use`, and scope are validated.\n\nAdditionally, we added [CodeQL scanning](https://github.com/ory/oathkeeper/commit/64ac7562669287d391cd72dfd43c5d71ff9f89a1) to the CI.",
"id": "GHSA-qvp4-rpmr-xwrr",
"modified": "2021-06-22T20:50:44Z",
"published": "2021-06-23T18:00:20Z",
"references": [
{
"type": "WEB",
"url": "https://github.com/ory/oathkeeper/security/advisories/GHSA-qvp4-rpmr-xwrr"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N",
"type": "CVSS_V3"
}
],
"summary": "Possible bypass of token claim validation when OAuth2 Introspection caching is enabled"
}
Sightings
| Author | Source | Type | Date |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or observed by the user.
- Confirmed: The vulnerability has been validated from an analyst's perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
- Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
- Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
- Not confirmed: The user expressed doubt about the validity of the vulnerability.
- Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.