Advisory Details

January 21st, 2021

Microsoft Windows splwow64 Out-Of-Bounds Read Privilege Escalation Vulnerability

ZDI-21-078
ZDI-CAN-12782

CVE ID CVE-2021-1648
CVSS SCORE 7.8, (AV:L/AC:L/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 user-supplied data, which can result in a read past the end of an allocated buffer. 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
  • 2021-01-05 - Vulnerability reported to vendor
  • 2021-01-21 - Coordinated public release of advisory
CREDIT Elliot Cao (@iamelli0t) working with Trend Micro's Zero Day Initiative
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