CVE Vulnerabilities

CVE-2021-36286

Improper Link Resolution Before File Access ('Link Following')

Published: Sep 28, 2021 | Modified: Oct 25, 2022
CVSS 3.x
7.1
HIGH
Source:
NVD
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:H
CVSS 2.x
3.6 LOW
AV:L/AC:L/Au:N/C:N/I:P/A:P
RedHat/V2
RedHat/V3
Ubuntu

Dell SupportAssist Client Consumer versions 3.9.13.0 and any versions prior to 3.9.13.0 contain an arbitrary file deletion vulnerability that can be exploited by using the Windows feature of NTFS called Symbolic links. Symbolic links can be created by any(non-privileged) user under some object directories, but by themselves are not sufficient to successfully escalate privileges. However, combining them with a different object, such as the NTFS junction point allows for the exploitation. Support assist clean files functionality do not distinguish junction points from the physical folder and proceeds to clean the target of the junction that allows nonprivileged users to create junction points and delete arbitrary files on the system which can be accessed only by the admin.

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
Supportassist_client_consumer Dell * 3.9.13.0 (including)

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.

References