Western Digital WD My Cloud v04.05.00-320 devices embed the session token (aka PHPSESSID) in filenames, which makes it easier for attackers to bypass authentication by listing a directory. NOTE: this can be exploited in conjunction with CVE-2018-7171 for remote authentication bypass within a product that uses My Cloud.

My Cloud OS 5 was vulnerable to a pre-authenticated stack overflow vulnerability on the FTP service that could be exploited by unauthenticated attackers on the network. Addressed the vulnerability by adding defenses against stack overflow issues.

A device API endpoint was missing access controls on Western Digital My Cloud OS 5 iOS and Anroid Mobile Apps, My Cloud Home iOS and Android Mobile Apps, SanDisk ibi iOS and Android Mobile Apps, My Cloud OS 5 Web App, My Cloud Home Web App and the SanDisk ibi Web App. Due to a permissive CORS policy and missing authentication requirement for private IPs, a remote attacker on the same network as the device could obtain device information by convincing a victim user to visit an attacker-controlled server and issue a cross-site request.

This issue affects My Cloud OS 5 Mobile App: before 4.21.0; My Cloud Home Mobile App: before 4.21.0; ibi Mobile App: before 4.21.0; My Cloud OS 5 Web App: before 4.26.0-6126; My Cloud Home Web App: before 4.26.0-6126; ibi Web App: before 4.26.0-6126.