CWE-1386: Insecure Operation on Windows Junction / Mount Point
CWE版本: 4.18
更新日期: 2025-09-09
弱点描述
The product opens a file or directory, but it does not properly prevent the name from being associated with a junction or mount point to a destination that is outside of the intended control sphere.
常见后果
影响范围: Confidentiality
技术影响: Read Files or Directories
说明: Read arbitrary files by replacing a user-controlled folder with a mount point and additional hard links.
影响范围: Integrity
技术影响: Modify Files or Directories
说明: Modify an arbitrary file by replacing the rollback files in installer directories, as they can have the installer execute those rollbacks.
影响范围: Availability
技术影响: Modify Files or Directories
说明: Even if there is no control of contents, an arbitrary file delete or overwrite (when running as SYSTEM or admin) can be used for a permanent system denial-of-service, e.g. by deleting a startup configuration file that prevents the service from starting.
潜在缓解措施
阶段: Architecture and Design
策略: Separation of Privilege
描述: When designing software that will have different rights than the executer, the software should check that files that it is interacting with are not improper hard links or mount points. One way to do this in Windows is to use the functionality embedded in the following command: "dir /al /s /b" or, in PowerShell, use LinkType as a filter. In addition, some software uses authentication via signing to ensure that the file is the correct one to use. Make checks atomic with the file action, otherwise a TOCTOU weakness (CWE-367) can be introduced.
观察示例
参考: CVE-2021-26426
Privileged service allows attackers to delete unauthorized files using a directory junction, leading to arbitrary code execution as SYSTEM.
参考: CVE-2020-0863
By creating a mount point and hard links, an attacker can abuse a service to allow users arbitrary file read permissions.
参考: CVE-2019-1161
Chain: race condition (CWE-362) in anti-malware product allows deletion of files by creating a junction (CWE-1386) and using hard links during the time window in which a temporary file is created and deleted.
参考: CVE-2014-0568
Escape from sandbox for document reader by using a mountpoint [REF-1264]
引入模式
| 阶段 | 说明 |
|---|---|
| Implementation | The developer might not consider that when a program in Windows operates with different permissions than the executing user, the use of links, mount points, and junctions might cause the program to access files or directories that are outside of the intended storage location. |