Advisory Details

January 14th, 2021

Microsoft Windows splwow64 Untrusted Pointer Dereference Privilege Escalation Vulnerability

ZDI-21-022
ZDI-CAN-12033

CVE ID CVE-2021-1648
CVSS SCORE 7.0, (AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H)
AFFECTED VENDORS Microsoft
AFFECTED PRODUCTS Windows
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
CREDIT Elliot Cao (@iamelli0t) working with Trend Micro's Zero Day Initiative
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