Arbitrary file write in Mitel MiVoice Office 400 backup restoration

DigitalCanion has discovered a vulnerability in the backup restoration functionality that allows an attacker with access to the configured backup repository to introduce arbitrary files into the system during restoration. The specific flaw exists within the backup restoration mechanism, which fails to properly validate the paths, file types, integrity, and authenticity of files contained within a restored TGZ archive. The application does not perform file-signature verification before extracting the archive, allowing a specially crafted backup to contain attacker-controlled files. An attacker with access to the backup SFTP or other configured repository can therefore provide a malicious TGZ archive that, when restored by the system, may place arbitrary files on the underlying Linux system. Depending on the location and permissions of the extracted files, this behavior can potentially be leveraged to achieve arbitrary code execution with root privileges and compromise the underlying virtual machine. The absence of enforced backup passwords further reduces the protection provided by the backup mechanism and may facilitate unauthorized access to the repository.