GHSA-2ccf-ffrj-m4qw
CSRF token fixation in fastify-passport
Packages
| Ecosystem | Package | Affected | Fixed in |
|---|---|---|---|
| npm | @fastify/passport | < 1.1.0 | 1.1.0 |
| npm | @fastify/passport | >= 2.0.0, < 2.3.0 | 2.3.0 |
Details
As written in the advisory (Markdown source, shown as plain text).
The [CSRF](https://owasp.org/www-community/attacks/csrf) protection enforced by the `@fastify/csrf-protection` library, when combined with `@fastify/passport`, can be bypassed by network and same-site attackers.
## Details
`fastify/csrf-protection` implements the [synchronizer token pattern](https://cheatsheetseries.owasp.org/cheatsheets/Cross-Site_Request_Forgery_Prevention_Cheat_Sheet.html#synchronizer-token-pattern) (using plugins `@fastify/session` and `@fastify/secure-session`) by storing a random value used for CSRF token generation in the `_csrf` attribute of a user's session.
The `@fastify/passport` library does not clear the session object upon authentication, preserving the `_csrf` attribute between pre-login and authenticated sessions. Consequently, CSRF tokens generated before authentication are still valid. Network and [same-site attackers](https://canitakeyoursubdomain.name/) can thus obtain a CSRF token for their pre-session, fixate that pre-session in the victim's browser via cookie tossing, and then perform a CSRF attack after the victim authenticates.
## Fix
As a solution, newer versions of `@fastify/passport` include the configuration options
* `clearSessionOnLogin (default: true)` and
* `clearSessionIgnoreFields (default: ['session'])`
to clear all the session attributes by default, preserving those explicitly defined in `clearSessionIgnoreFields`.
## Credits
* Pedro Adão (@pedromigueladao), [Instituto Superior Técnico, University of Lisbon](https://tecnico.ulisboa.pt/)
* Marco Squarcina (@lavish), [Security & Privacy Research Unit, TU Wien](https://secpriv.wien/)
References
External links from the advisory. They lead to third-party sites.
- https://github.com/fastify/fastify-passport/security/advisories/GHSA-2ccf-ffrj-m4qw
- https://nvd.nist.gov/vuln/detail/CVE-2023-29020
- https://github.com/fastify/fastify-passport/commit/07c90feab9cba0dd4779e47cfb0717a7e2f01d3d
- https://cheatsheetseries.owasp.org/cheatsheets/Cross-Site_Request_Forgery_Prevention_Cheat_Sheet.html#synchronizer-token-pattern
- https://github.com/fastify/fastify-passport
- https://owasp.org/www-community/attacks/csrf