CVE-2020-5415

Concourse, versions prior to 6.3.1 and 6.4.1, in installations which use the GitLab auth connector, is vulnerable to identity spoofing by way of configuring a GitLab account with the same full name as another user who is granted access to a Concourse team. GitLab groups do not have this vulnerability, so GitLab users may be moved into groups which are then configured in the Concourse team.

Concourse, versions prior to 6.3.1 and 6.4.1, in installations which use the GitLab auth connector, is vulnerable to identity spoofing by way of configuring a GitLab account with the same full name as another user who is granted access to a Concourse team. GitLab groups do not have this vulnerability, so GitLab users may be moved into groups which are then configured in the Concourse team.

### Impact Installations which use the GitLab auth connector are vulnerable to identity spoofing by way of configuring a GitLab account with the same full name as another GitLab user who is granted access to a Concourse team by having their full name listed under `users` in the team configuration or given to the `--gitlab-user` flag. See the [GitLab auth docs](https://concourse-ci.org/gitlab-auth.html) for details. Concourse installations which do not configure the GitLab auth connector are not affected. ### Patches Concourse [v6.3.1](https://github.com/concourse/concourse/releases/tag/v6.3.1) and [v6.4.1](https://github.com/concourse/concourse/releases/tag/v6.4.1) were both released with a fix on August 4th, 2020. Both versions change the GitLab connector to use the username, rather than the full name. This was always the intent, and the previous behavior was originally reported as a bug (concourse/dex#7) prior to being reported as a security issue. Any Concourse teams which configure GitLab users will have to switch each user from their full name to their username upon upgrading to these versions. ### Workarounds GitLab groups do not have this vulnerability, so GitLab users may be moved into groups which are then configured in the Concourse team. ### References * concourse/dex#12: PR with the fix ### For more information If you have any questions or comments about this advisory, you may reach us privately at [concourseteam+security@gmail.com](mailto:concourseteam+security@gmail.com).

### Impact Installations which use the GitLab auth connector are vulnerable to identity spoofing by way of configuring a GitLab account with the same full name as another GitLab user who is granted access to a Concourse team by having their full name listed under `users` in the team configuration or given to the `--gitlab-user` flag. See the [GitLab auth docs](https://concourse-ci.org/gitlab-auth.html) for details. Concourse installations which do not configure the GitLab auth connector are not affected. ### Patches Concourse [v6.3.1](https://github.com/concourse/concourse/releases/tag/v6.3.1) and [v6.4.1](https://github.com/concourse/concourse/releases/tag/v6.4.1) were both released with a fix on August 4th, 2020. Both versions change the GitLab connector to use the username, rather than the full name. This was always the intent, and the previous behavior was originally reported as a bug (concourse/dex#7) prior to being reported as a security issue. Any Concourse teams which configure GitLab users will have to switch each user from their full name to their username upon upgrading to these versions. ### Workarounds GitLab groups do not have this vulnerability, so GitLab users may be moved into groups which are then configured in the Concourse team. ### References * concourse/dex#12: PR with the fix ### For more information If you have any questions or comments about this advisory, you may reach us privately at [concourseteam+security@gmail.com](mailto:concourseteam+security@gmail.com).

Concourse, versiones anteriores a 6.3.1 y 6.4.1, en instalaciones que utilizan el conector de autenticación de GitLab, es vulnerable a la suplantación de identidad mediante la configuración de una cuenta de GitLab con el mismo nombre completo que otro usuario al que se le concede acceso a un equipo de Concourse. Los grupos de GitLab no tienen esta vulnerabilidad, por lo que los usuarios de GitLab pueden ser movidos a grupos que luego son configurados en el equipo de Concourse