An issue was discovered in open-vm-tools 2009.03.18-154848. Local users can bypass intended access restrictions on mounting shares via a symlink attack that leverages a realpath race condition in mount.vmhgfs (aka hgfsmounter).
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
| Name | Vendor | Start Version | End Version |
|---|---|---|---|
| Open-vm-tools | Vmware | 2009.03.18-154848 (including) | 2009.03.18-154848 (including) |
| Open-vm-tools | Ubuntu | bionic | * |
| Open-vm-tools | Ubuntu | esm-infra-legacy/trusty | * |
| Open-vm-tools | Ubuntu | esm-infra/bionic | * |
| Open-vm-tools | Ubuntu | esm-infra/focal | * |
| Open-vm-tools | Ubuntu | esm-infra/xenial | * |
| Open-vm-tools | Ubuntu | focal | * |
| Open-vm-tools | Ubuntu | trusty | * |
| Open-vm-tools | Ubuntu | trusty/esm | * |
| Open-vm-tools | Ubuntu | xenial | * |
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