Microsoft Windows splwow64 Untrusted Pointer Dereference Privilege Escalation Vulnerability

January 14th, 2021

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 user-mode printer driver host process splwow64.exe. The issue results from the lack of proper validation of a user-supplied value prior to dereferencing it as a pointer. An attacker can leverage this vulnerability to escalate privileges from low integrity and execute arbitrary code in the context of the current user at medium integrity.

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-2021-1648

Disclosure Timeline

  • 2020-09-30 - Vulnerability reported to vendor
  • 2021-01-14 - Coordinated public release of advisory
  • 2021-06-29 - Advisory Updated

Credit

Elliot Cao (@iamelli0t) working with Trend Micro's Zero Day Initiative

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