CVE-2020-15129

In Traefik before versions 1.7.26, 2.2.8, and 2.3.0-rc3, there exists a potential open redirect vulnerability in Traefik's handling of the "X-Forwarded-Prefix" header. The Traefik API dashboard component doesn't validate that the value of the header "X-Forwarded-Prefix" is a site relative path and will redirect to any header provided URI. Successful exploitation of an open redirect can be used to entice victims to disclose sensitive information. Active Exploitation of this issue is unlikely as it would require active header injection, however the Traefik team addressed this issue nonetheless to prevent abuse in e.g. cache poisoning scenarios.

In Traefik before versions 1.7.26, 2.2.8, and 2.3.0-rc3, there exists a potential open redirect vulnerability in Traefik's handling of the "X-Forwarded-Prefix" header. The Traefik API dashboard component doesn't validate that the value of the header "X-Forwarded-Prefix" is a site relative path and will redirect to any header provided URI. Successful exploitation of an open redirect can be used to entice victims to disclose sensitive information. Active Exploitation of this issue is unlikely as it would require active header injection, however the Traefik team addressed this issue nonetheless to prevent abuse in e.g. cache poisoning scenarios.

## Summary There exists a potential open redirect vulnerability in Traefik's handling of the `X-Forwarded-Prefix` header. Active Exploitation of this issue is unlikely as it would require active header injection, however the Traefik team addressed this issue nonetheless to prevent abuse in e.g. cache poisoning scenarios. ## Details The Traefik API dashboard component doesn't validate that the value of the header `X-Forwarded-Prefix` is a site relative path and will redirect to any header provided URI. e.g. ``` $ curl --header 'Host:traefik.localhost' --header 'X-Forwarded-Prefix:https://example.org' 'http://localhost:8081' <a href="https://example.org/dashboard/">Found</a>.` ``` ### Impact A successful exploitation of an open redirect can be used to entice victims to disclose sensitive information. ### Workarounds By using the `headers` middleware, the request header `X-Forwarded-Prefix` value can be overridden by the value `.` (dot) - https://docs.traefik.io/v2.2/middlewares/headers/#customrequestheaders - https://docs.traefik.io/v1.7/basics/#custom-headers ### For more information If you have any questions or comments about this advisory, open an issue in [Traefik](https://github.com/containous/traefik/issues). ## Credit This issue was found by the GitHub Application Security Team and reported on behalf of the GHAS by the GitHub Security Lab Team.

## Summary There exists a potential open redirect vulnerability in Traefik's handling of the `X-Forwarded-Prefix` header. Active Exploitation of this issue is unlikely as it would require active header injection, however the Traefik team addressed this issue nonetheless to prevent abuse in e.g. cache poisoning scenarios. ## Details The Traefik API dashboard component doesn't validate that the value of the header `X-Forwarded-Prefix` is a site relative path and will redirect to any header provided URI. e.g. ``` $ curl --header 'Host:traefik.localhost' --header 'X-Forwarded-Prefix:https://example.org' 'http://localhost:8081' <a href="https://example.org/dashboard/">Found</a>.` ``` ### Impact A successful exploitation of an open redirect can be used to entice victims to disclose sensitive information. ### Workarounds By using the `headers` middleware, the request header `X-Forwarded-Prefix` value can be overridden by the value `.` (dot) - https://docs.traefik.io/v2.2/middlewares/headers/#customrequestheaders - https://docs.traefik.io/v1.7/basics/#custom-headers ### For more information If you have any questions or comments about this advisory, open an issue in [Traefik](https://github.com/containous/traefik/issues). ## Credit This issue was found by the GitHub Application Security Team and reported on behalf of the GHAS by the GitHub Security Lab Team.

En Traefik antes de las versiones 1.7.26, 2.2.8 y 2.3.0-rc3, se presenta una posible vulnerabilidad de redireccionamiento abierto en el manejo del encabezado "X-Forwarded-Prefix" de Traefik. El componente del panel de la API Traefik no comprueba que el valor del encabezado "X-Forwarded-Prefix" sea una ruta relativa al sitio y redireccionará a cualquier URI proporcionado por el encabezado. Una explotación con éxito de un redireccionamiento abierto puede ser utilizado para atraer a las víctimas a revelar información confidencial. Una explotación activa de este problema es poco probable ya que requeriría una inyección activa del encabezado, sin embargo, el equipo de Traefik abordó este problema para impedir el abuso en por ejemplo escenarios de envenenamiento de caché