Advisory Details

January 27th, 2021

(0Day) Microsoft Windows win32kfull bRotate NULL Pointer Dereference Privilege Escalation Vulnerability

ZDI-21-090
ZDI-CAN-12671

CVE ID
CVSS SCORE 7.8, (AV:L/AC:H/PR:L/UI:N/S:C/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 win32kfull.sys driver. The issue results from dereferencing a NULL pointer. An attacker can leverage this vulnerability to escalate privileges and execute arbitrary code in the context of SYSTEM.

ADDITIONAL DETAILS

This vulnerability is being disclosed publicly without a patch in accordance with the ZDI 120 day deadline.

12/23/20 – ZDI reported the vulnerability to the vendor
12/23/20 – The vendor acknowledged the report
12/28/20 – The vendor indicated the case does not meet the bar for servicing
01/19/21 – ZDI notified the vendor of the intention to publish the case as a 0-day advisory on 01/27/21

-- Mitigation:
Given the nature of the vulnerability the only salient mitigation strategy is to restrict interaction with the application.


DISCLOSURE TIMELINE
  • 2020-12-23 - Vulnerability reported to vendor
  • 2021-01-27 - Coordinated public release of advisory
CREDIT Marcin Wiazowski
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