Описание
OpenAM OAuth Authorization Bypass via PKCE Challenge
Summary
Description
An Improper Authorization (CWE-285) issue in OpenAM's OAuth2 authorization-code grant allows a PKCE-protected authorization code to be redeemed without the required code_verifier. This affects OpenAM Community Edition through version 16.0.6 and was patched in version 16.1.1.
The authorize endpoint stores a code_challenge on the issued code, but the token endpoint only requires a code_verifier when the realm-wide codeVerifierEnforced setting is enabled, which ships disabled by default. With that setting off, the stored challenge is checked only if the caller supplies a verifier, so omitting the parameter skips PKCE verification entirely.
Impact
OpenAM Community Edition deployments through version 16.0.6 using the default OAuth2 provider configuration are potentially affected. For public clients, an attacker who intercepts an authorization code can exchange it for tokens without knowing the verifier. For confidential clients, the attacker additionally needs client authentication material or an execution context that can redeem the code. A token request supplying an incorrect verifier is still rejected. The bypass is specifically the missing-parameter path.
Patch
This has been patched in OpenAM Community Edition version 16.1.1. Users are encouraged to update to the latest release.
Пакеты
org.openidentityplatform.openam:openam-oauth2
<= 16.0.6
16.1.1
Связанные уязвимости
(Open Access Management (OpenAM) is an access management solution. Prio ...)
Open Access Management (OpenAM) is an access management solution. Prior to 16.1.1, AuthorizationCodeGrantTypeHandler requires a code_verifier only when the realm-wide codeVerifierEnforced setting is enabled, even when an authorization code stores a code_challenge. Because that setting is disabled by default, an attacker who intercepts a PKCE-protected authorization code can omit code_verifier and redeem the code, while an explicitly incorrect verifier is rejected. Public clients are directly affected, and confidential-client exploitation additionally requires client authentication material or another redemption context. This issue is fixed in version 16.1.1.