Bug 2188472 (CVE-2023-27495) - CVE-2023-27495 fastify-csrf: Bypass of CSRF protection in the presence of predictable userInfo
Summary: CVE-2023-27495 fastify-csrf: Bypass of CSRF protection in the presence of pre...
Keywords:
Status: CLOSED NOTABUG
Alias: CVE-2023-27495
Product: Security Response
Classification: Other
Component: vulnerability
Version: unspecified
Hardware: All
OS: Linux
medium
medium
Target Milestone: ---
Assignee: Red Hat Product Security
QA Contact:
URL:
Whiteboard:
Depends On:
Blocks: 2188473
TreeView+ depends on / blocked
 
Reported: 2023-04-20 20:59 UTC by Pedro Sampaio
Modified: 2023-04-27 18:17 UTC (History)
2 users (show)

Fixed In Version:
Clone Of:
Environment:
Last Closed: 2023-04-27 18:17:24 UTC
Embargoed:


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Description Pedro Sampaio 2023-04-20 20:59:25 UTC
@fastify/csrf-protection is a plugin which helps protect Fastify servers against CSRF attacks. The CSRF protection enforced by the @fastify/csrf-protection library in combination with @fastify/cookie can be bypassed from network and same-site attackers under certain conditions. @fastify/csrf-protection supports an optional userInfo parameter that binds the CSRF token to the user. This parameter has been introduced to prevent cookie-tossing attacks as a fix for CVE-2021-29624. Whenever userInfo parameter is missing, or its value can be predicted for the target user account, network and same-site attackers can 1. fixate a _csrf cookie in the victim's browser, and 2. forge CSRF tokens that are valid for the victim's session. This allows attackers to bypass the CSRF protection mechanism. As a fix, @fastify/csrf-protection starting from version 6.3.0 (and v4.1.0) includes a server-defined secret hmacKey that cryptographically binds the CSRF token to the value of the _csrf cookie and the userInfo parameter, making tokens non-spoofable by attackers. This protection is effective as long as the userInfo parameter is unique for each user. This is patched in versions 6.3.0 and v4.1.0. Users are advised to upgrade. Users unable to upgrade may use a random, non-predictable userInfo parameter for each user as a mitigation.

References:

https://github.com/fastify/csrf-protection/security/advisories/GHSA-qrgf-9gpc-vrxw
https://github.com/fastify/csrf-protection/commit/be3e5761f37aa05c7c1ac8ed44499c51ecec8058
https://github.com/fastify/csrf-protection/commit/be3e5761f37aa05c7c1ac8ed44499c51ecec8058

Comment 1 Zack Miele 2023-04-27 18:17:24 UTC
This plugin is not part of the core fastify plugin set or added as a plugin to devspaces.


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