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Microsoft Windows SilentCleanup Link Following Local Privilege Escalation Vulnerability

January 13th, 2022

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 the SilentCleanup scheduled task. By creating a symbolic link, an attacker can abuse the task to delete a folder. An attacker can leverage this vulnerability to escalate privileges and execute arbitrary 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-2022-21838

Disclosure Timeline

  • 2021-09-03 - Vulnerability reported to vendor
  • 2022-01-13 - Coordinated public release of advisory

Credit

Abdelhamid Naceri

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