Improper access control in Windows Container Isolation FS Filter Driver (unionfs.sys) allows an authorized attacker to elevate privileges locally.
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 |
|---|---|---|---|
| Windows_11_23h2 | Microsoft | * | 10.0.22631.7652 (excluding) |
| Windows_11_24h2 | Microsoft | * | 10.0.26100.9711 (excluding) |
| Windows_11_25h2 | Microsoft | * | 10.0.26200.9711 (excluding) |
| Windows_11_26h1 | Microsoft | * | 10.0.28000.3231 (excluding) |
| Windows_11_26h2 | Microsoft | * | 10.0.26300.9711 (excluding) |
| Windows_server_2022 | Microsoft | * | 10.0.20348.5761 (excluding) |
| Windows_server_2025 | Microsoft | * | 10.0.26100.33650 (excluding) |
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