An uncontrolled resource consumption vulnerability issue that could arise by sending crafted requests to a service to consume a large amount of memory, eventually resulting in the service being stopped and restarted was discovered in Western Digital My Cloud Home, My Cloud Home Duo, SanDisk ibi and Western Digital My Cloud OS 5 devices. This issue requires the attacker to already have root privileges in order to exploit this vulnerability. This issue affects My Cloud Home and My Cloud Home Duo: before 9.5.1-104; ibi: before 9.5.1-104; My Cloud OS 5: before 5.27.161.

Server-side request forgery (SSRF) vulnerability that could allow a rogue server on the local network to modify its URL using another DNS address to point back to the loopback adapter. This could then allow the URL to exploit other vulnerabilities on the local server. This was addressed by fixing DNS addresses that refer to loopback. This issue affects My Cloud OS 5 devices before 5.27.161, My Cloud Home, My Cloud Home Duo and SanDisk ibi devices before 9.5.1-104. 

Western Digital My Cloud, My Cloud Home, My Cloud Home Duo, and SanDisk ibi devices were vulnerable to an impersonation attack that could allow an unauthenticated attacker to gain access to user data. This issue affects My Cloud OS 5 devices: before 5.25.132; My Cloud Home and My Cloud Home Duo: before 8.13.1-102; SanDisk ibi: before 8.13.1-102.

A vulnerability in the FTP service of Western Digital My Cloud OS 5 devices running firmware versions prior to 5.26.119 allows an attacker to read and write arbitrary files. This could lead to a full NAS compromise and would give remote execution capabilities to the attacker.

A command injection vulnerability in the DDNS service configuration of Western Digital My Cloud OS 5 devices running firmware versions prior to 5.26.119 allows an attacker to execute code in the context of the root user.

The Western Digital My Cloud Web App [https://os5.mycloud.com/] uses a weak SSLContext when attempting to configure port forwarding rules. This was enabled to maintain compatibility with old or outdated home routers. By using an "SSL" context instead of "TLS" or specifying stronger validation, deprecated or insecure protocols are permitted. As a result, a local user with no privileges can exploit this vulnerability and jeopardize the integrity, confidentiality and authenticity of information transmitted. The scope of impact cannot extend to other components and no user input is required to exploit this vulnerability.

Western Digital My Cloud devices are vulnerable to a cross side scripting vulnerability that can allow a malicious user with elevated privileges access to drives being backed up to construct and inject JavaScript payloads into an authenticated user's browser. As a result, it may be possible to gain control over the authenticated session, steal data, modify settings, or redirect the user to malicious websites. The scope of impact can extend to other components.

The combination of primitives offered by SMB and AFP in their default configuration allows the arbitrary writing of files. By exploiting these combination of primitives, an attacker can execute arbitrary code.

Western Digital My Cloud Cloud, Mirror Gen2, EX2 Ultra, EX2100, EX4100, DL2100, DL4100, PR2100 and PR4100 before firmware 2.31.183 are affected by a code execution (as root, starting from a low-privilege user session) vulnerability. The cgi-bin/webfile_mgr.cgi file allows arbitrary file write by abusing symlinks. Specifically, this occurs by uploading a tar archive that contains a symbolic link, then uploading another archive that writes a file to the link using the "cgi_untar" command. Other commands might also be susceptible. Code can be executed because the "name" parameter passed to the cgi_unzip command is not sanitized.

Western Digital My Cloud, My Cloud Mirror Gen2, My Cloud EX2 Ultra, My Cloud EX2100, My Cloud EX4100, My Cloud DL2100, My Cloud DL4100, My Cloud PR2100 and My Cloud PR4100 firmware before 2.31.174 is affected by an authentication bypass vulnerability. The login_mgr.cgi file checks credentials against /etc/shadow. However, the "nobody" account (which can be used to access the control panel API as a low-privilege logged-in user) has a default empty password, allowing an attacker to modify the My Cloud EX2 Ultra web page source code and obtain access to the My Cloud as a non-Admin My Cloud device user.