Microsoft Windows Setup Directory Junction Privilege Escalation Vulnerability
Vulnerability Details
This vulnerability allows local attackers to escalate privileges on affected installations of Microsoft Windows. An attacker must first obtain the ability to execute low-privileged code on the target system in order to exploit this vulnerability.
The specific flaw exists within Windows Setup. By creating a directory junction, an attacker can abuse Windows Setup to create a file in an arbitrary location. An attacker can leverage this vulnerability to escalate privileges and execute code in the context of SYSTEM.
Additional Details
Microsoft has issued an update to correct this vulnerability. More details can be found at:
https://msrc.microsoft.com/update-guide/vulnerability/CVE-2021-26889
Disclosure Timeline
- 2020-11-11 - Vulnerability reported to vendor
- 2021-03-17 - Coordinated public release of advisory
Credit
Abdelhamid Naceri (halov)
