CVE-2019-13226

deepin-clone before 1.1.3 uses a predictable path /tmp/.deepin-clone/mount/ in the Helper::temporaryMountDevice() function to temporarily mount a file system as root. An unprivileged user can prepare a symlink at this location to have the file system mounted in an arbitrary location. By winning a race condition, the attacker can also enter the mount point, thereby preventing a subsequent unmount of the file system.

Weakness

The product attempts to access a file based on the filename, but it does not properly prevent that filename from identifying a link or shortcut that resolves to an unintended resource.

Affected Software

Potential Mitigations

• Follow the principle of least privilege when assigning access rights to entities in a software system.
• Denying access to a file can prevent an attacker from replacing that file with a link to a sensitive file. Ensure good compartmentalization in the system to provide protected areas that can be trusted.

Related Attack Patterns

• https://cwe.mitre.org/data/definitions/132.html
• https://cwe.mitre.org/data/definitions/17.html
• https://cwe.mitre.org/data/definitions/35.html
• https://cwe.mitre.org/data/definitions/76.html

References

• http://www.openwall.com/lists/oss-security/2019/07/04/1
• https://bugzilla.suse.com/show_bug.cgi?id=1130388
• https://github.com/linuxdeepin/deepin-clone/commit/e079f3e2712b4f8c28e3e63e71ba1a1f90fce1ab
• https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/TCHGRJV5CWTMYEE5B5C2FNMCFVP45S7H/
• http://www.openwall.com/lists/oss-security/2019/07/04/1
• https://bugzilla.suse.com/show_bug.cgi?id=1130388
• https://github.com/linuxdeepin/deepin-clone/commit/e079f3e2712b4f8c28e3e63e71ba1a1f90fce1ab
• https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/TCHGRJV5CWTMYEE5B5C2FNMCFVP45S7H/