CVE-2020-12852: Input Validation

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”.