Western Digital My Cloud Cloud, Mirror Gen2, EX2 Ultra, EX2100,...

Vulnerability Description

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.

References

• https://community.wd.com/t/new-release-my-cloud-firmware-versions-2-31-183-05-20-2019/237717
• https://bnbdr.github.io/posts/wd/
• https://github.com/bnbdr/wd-rce/