CVE-2021-32786 Information

Description

mod_auth_openidc is an authentication/authorization module for the Apache 2.x HTTP server that functions as an OpenID Connect Relying Party authenticating users against an OpenID Connect Provider. In versions prior to 2.4.9 oidc_validate_redirect_url() does not parse URLs the same way as most browsers do. As a result this function can be bypassed and leads to an Open Redirect vulnerability in the logout functionality. This bug has been fixed in version 2.4.9 by replacing any backslash of the URL to redirect with slashes to address a particular breaking change between the different specifications (RFC2396 / RFC3986 and WHATWG). As a workaround this vulnerability can be mitigated by configuring mod_auth_openidc to only allow redirection whose destination matches a given regular expression.

CVSS Vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

Reference

https://daniel.haxx.se/blog/2017/01/30/one-url-standard-please/ https://daniel.haxx.se/blog/2017/01/30/one-url-standard-please/ https://github.com/zmartzone/mod_auth_openidc/releases/tag/v2.4.9 https://github.com/zmartzone/mod_auth_openidc/commit/3a115484eb927bc6daa5737dd84f88ff4bbc5544 https://github.com/zmartzone/mod_auth_openidc/security/advisories/GHSA-xm4c-5wm5-jqv7 https://lists.fedoraproject.org/archives/list/[email protected]/message/QXAWKPT5LXZSUTFSJ6IWSZC7RMYYQXQD/ https://lists.fedoraproject.org/archives/list/[email protected]/message/FZVF6BSJLRQZ7PFFR4X5JSU6KUJYNOCU/ https://security.netapp.com/advisory/ntap-20210902-0001/ https://www.oracle.com/security-alerts/cpuapr2022.html mod_auth_openidc is an authentication/authorization module for the Apache 2.x HTTP server that functions as an OpenID Connect Relying Party authenticating users against an OpenID Connect Provider. In versions prior to 2.4.9 oidc_validate_redirect_url() does not parse URLs the same way as most browsers do. As a result this function can be bypassed and leads to an Open Redirect vulnerability in the logout functionality. This bug has been fixed in version 2.4.9 by replacing any backslash of the URL to redirect with slashes to address a particular breaking change between the different specifications (RFC2396 / RFC3986 and WHATWG). As a workaround this vulnerability can be mitigated by configuring mod_auth_openidc to only allow redirection whose destination matches a given regular expression.

Attack Complexity

LOW

Privileges Required

NONE

User Interaction Required

NONE

Scope

REQUIRED

Confidentiality Impact

CHANGED

Integrity Impact

LOW

Availability Impact

LOW

Base Score

NONE

Base Severity

6.1