Описание
Puma with proxy which forwards LF characters as line endings could allow HTTP request smuggling
Impact
Prior to puma version 5.5.0, using puma with a proxy which forwards LF characters as line endings could allow HTTP request smuggling. A client could smuggle a request through a proxy, causing the proxy to send a response back to another unknown client.
This behavior (forwarding LF characters as line endings) is very uncommon amongst proxy servers, so we have graded the impact here as "low". Puma is only aware of a single proxy server which has this behavior.
If the proxy uses persistent connections and the client adds another request in via HTTP pipelining, the proxy may mistake it as the first request's body. Puma, however, would see it as two requests, and when processing the second request, send back a response that the proxy does not expect. If the proxy has reused the persistent connection to Puma to send another request for a different client, the second response from the first client will be sent to the second client.
Patches
This vulnerability was patched in Puma 5.5.1 and 4.3.9.
Workarounds
This vulnerability only affects Puma installations without any proxy in front.
Use a proxy which does not forward LF characters as line endings.
Proxies which do not forward LF characters as line endings:
- Nginx
- Apache (>2.4.25)
- Haproxy
- Caddy
- Traefik
Possible Breakage
If you are dealing with legacy clients that want to send LF as a line ending in an HTTP header, this will cause those clients to receive a 400 error.
References
For more information
If you have any questions or comments about this advisory:
- Open an issue in Puma
- See our security policy
Ссылки
- https://github.com/puma/puma/security/advisories/GHSA-48w2-rm65-62xx
- https://nvd.nist.gov/vuln/detail/CVE-2021-41136
- https://github.com/puma/puma/commit/436c71807f00e07070902a03f79fd3e130eb6b18
- https://github.com/puma/puma/commit/acdc3ae571dfae0e045cf09a295280127db65c7f
- https://github.com/puma/puma/commit/fb6ad8f8013ab5cdbb2f444cbfabd0b4fde71139
- https://github.com/puma/puma/releases/tag/v4.3.9
- https://github.com/puma/puma/releases/tag/v5.5.1
- https://github.com/rubysec/ruby-advisory-db/blob/master/gems/puma/CVE-2021-41136.yml
- https://lists.debian.org/debian-lts-announce/2022/08/msg00015.html
- https://security.gentoo.org/glsa/202208-28
- https://www.debian.org/security/2022/dsa-5146
Пакеты
puma
>= 5.0.0, < 5.5.1
5.5.1
puma
< 4.3.9
4.3.9
Связанные уязвимости
Puma is a HTTP 1.1 server for Ruby/Rack applications. Prior to versions 5.5.1 and 4.3.9, using `puma` with a proxy which forwards HTTP header values which contain the LF character could allow HTTP request smugggling. A client could smuggle a request through a proxy, causing the proxy to send a response back to another unknown client. The only proxy which has this behavior, as far as the Puma team is aware of, is Apache Traffic Server. If the proxy uses persistent connections and the client adds another request in via HTTP pipelining, the proxy may mistake it as the first request's body. Puma, however, would see it as two requests, and when processing the second request, send back a response that the proxy does not expect. If the proxy has reused the persistent connection to Puma to send another request for a different client, the second response from the first client will be sent to the second client. This vulnerability was patched in Puma 5.5.1 and 4.3.9. As a workaround, do not us...
Puma is a HTTP 1.1 server for Ruby/Rack applications. Prior to versions 5.5.1 and 4.3.9, using `puma` with a proxy which forwards HTTP header values which contain the LF character could allow HTTP request smugggling. A client could smuggle a request through a proxy, causing the proxy to send a response back to another unknown client. The only proxy which has this behavior, as far as the Puma team is aware of, is Apache Traffic Server. If the proxy uses persistent connections and the client adds another request in via HTTP pipelining, the proxy may mistake it as the first request's body. Puma, however, would see it as two requests, and when processing the second request, send back a response that the proxy does not expect. If the proxy has reused the persistent connection to Puma to send another request for a different client, the second response from the first client will be sent to the second client. This vulnerability was patched in Puma 5.5.1 and 4.3.9. As a workaround, do not us...
Puma is a HTTP 1.1 server for Ruby/Rack applications. Prior to versions 5.5.1 and 4.3.9, using `puma` with a proxy which forwards HTTP header values which contain the LF character could allow HTTP request smugggling. A client could smuggle a request through a proxy, causing the proxy to send a response back to another unknown client. The only proxy which has this behavior, as far as the Puma team is aware of, is Apache Traffic Server. If the proxy uses persistent connections and the client adds another request in via HTTP pipelining, the proxy may mistake it as the first request's body. Puma, however, would see it as two requests, and when processing the second request, send back a response that the proxy does not expect. If the proxy has reused the persistent connection to Puma to send another request for a different client, the second response from the first client will be sent to the second client. This vulnerability was patched in Puma 5.5.1 and 4.3.9. As a workaround, do not use A
Puma is a HTTP 1.1 server for Ruby/Rack applications. Prior to version ...
Уязвимость HTTP-сервера для Ruby/Rack приложений Puma, позволяющая нарушителю получить доступ к конфиденциальной информации