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Pac4j token validation bypass if OpenID Connect provider supports none algorithm

High severity GitHub Reviewed Published Jan 8, 2022 to the GitHub Advisory Database • Updated Sep 26, 2023

Package

maven org.pac4j:pac4j-oidc (Maven)

Affected versions

< 4.5.5
>= 5.0, < 5.3.1

Patched versions

4.5.5
5.3.1

Description

If an OpenID Connect provider supports the “none” algorithm (i.e., tokens with no signature), pac4j v5.3.0 (and prior) does not refuse it without an explicit configuration on its side or for the “idtoken” response type which is not secure and violates the OpenID Core Specification. The "none" algorithm does not require any signature verification when validating the ID tokens, which allows the attacker to bypass the token validation by injecting a malformed ID token using "none" as the value of "alg" key in the header with an empty signature value.

References

Published by the National Vulnerability Database Jan 6, 2022
Reviewed Jan 7, 2022
Published to the GitHub Advisory Database Jan 8, 2022
Last updated Sep 26, 2023

Severity

High

CVSS overall score

This score calculates overall vulnerability severity from 0 to 10 and is based on the Common Vulnerability Scoring System (CVSS).
/ 10

CVSS v3 base metrics

Attack vector
Network
Attack complexity
Low
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
High
Availability
None

CVSS v3 base metrics

Attack vector: More severe the more the remote (logically and physically) an attacker can be in order to exploit the vulnerability.
Attack complexity: More severe for the least complex attacks.
Privileges required: More severe if no privileges are required.
User interaction: More severe when no user interaction is required.
Scope: More severe when a scope change occurs, e.g. one vulnerable component impacts resources in components beyond its security scope.
Confidentiality: More severe when loss of data confidentiality is highest, measuring the level of data access available to an unauthorized user.
Integrity: More severe when loss of data integrity is the highest, measuring the consequence of data modification possible by an unauthorized user.
Availability: More severe when the loss of impacted component availability is highest.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N

EPSS score

0.251%
(65th percentile)

Weaknesses

CVE ID

CVE-2021-44878

GHSA ID

GHSA-xhw6-hjc9-679m

Source code

Credits

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