Advisory Details

July 19th, 2021

(Pwn2Own) Microsoft Windows spaceport Out-Of-Bounds Write Privilege Escalation Vulnerability

ZDI-21-824
ZDI-CAN-13561

CVE ID CVE-2021-33751
CVSS SCORE 8.8, AV:L/AC:L/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 spaceport.sys driver. The issue results from the lack of proper validation of user-supplied data, which can result in a write past the end of an allocated buffer. 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-2021-33751
DISCLOSURE TIMELINE
  • 2021-04-22 - Vulnerability reported to vendor
  • 2021-07-19 - Coordinated public release of advisory
CREDIT Fabien Perigaud (@0xf4b) from Synacktiv (@Synacktiv)
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