The following vulnerability applies only to the Pydio Cells Enterprise OVF version 2.0.4. Prior versions of the Pydio Cells Enterprise OVF (such as version 2.0.3) have a looser policy restriction allowing the “pydio” user to execute any privileged command using sudo. In version 2.0.4 of the appliance, the user pydio is responsible for running all the services and binaries that are contained in the Pydio Cells web application package, such as mysqld, cells, among others. This user has privileges restricted to run those services and nothing more.

Pydio Cells 2.0.4 web application offers an administrative console named “Cells Console” that is available to users with an administrator role. This console provides an administrator user with the possibility of changing several settings, including the application’s mailer configuration. It is possible to configure a few engines to be used by the mailer application to send emails. If the user selects the “sendmail” option as the default one, the web application offers to edit the full path where the sendmail binary is hosted. Since there is no restriction in place while editing this value, an attacker authenticated as an administrator user could force the web application into executing any arbitrary binary.

The update feature for Pydio Cells 2.0.4 allows an administrator user to set a custom update URL and the public RSA key used to validate the downloaded update package. The update process involves downloading the updated binary file from a URL indicated in the update server response, validating its checksum and signature with the provided public key and finally replacing the current application binary. To complete the update process, the application’s service or appliance needs to be restarted. An attacker with administrator access can leverage the software update feature to force the application to download a custom binary that will replace current Pydio Cells binary. When the server or service is eventually restarted the attacker will be able to execute code under the privileges of the user running the application. In the Pydio Cells enterprise appliance this is with the privileges of the user named “pydio”.

Pydio Cells 2.0.4 allows any user to upload a profile image to the web application, including standard and shared user roles. These profile pictures can later be accessed directly with the generated URL by any unauthenticated or authenticated user.

Pydio Cells 2.0.4 allows an authenticated user to write or overwrite existing files in another user’s personal and cells folders (repositories) by uploading a custom generated ZIP file and leveraging the file extraction feature present in the web application. The extracted files will be placed in the targeted user folders.

Pydio Cells 2.0.4 allows XSS. A malicious user can either upload or create a new file that contains potentially malicious HTML and JavaScript code to personal folders or accessible cells.

In Pydio Cells 2.0.4, once an authenticated user shares a file selecting the create a public link option, a hidden shared user account is created in the backend with a random username. An anonymous user that obtains a valid public link can get the associated hidden account username and password and proceed to login to the web application. Once logged into the web application with the hidden user account, some actions that were not available with the public share link can now be performed.