TippingPoint Zero Day Initiative

(Pwn2Own) Microsoft Windows PlgBlt Integer Overflow Privilege Escalation Vulnerability

ZDI-17-473: July 11th, 2017


CVSS Score

Affected Vendors

Affected Products


Vulnerability Details

This vulnerability allows local attackers to escalate privileges on vulnerable 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 implementation of PlgBlt, an operation that writes bitmap graphics to parallelogram-shaped destination areas. The issue results from the lack of proper validation of user-supplied data, which can result in an integer overflow before writing to memory. An attacker can leverage this vulnerability to escalate privilege to the level of SYSTEM.

Vendor Response

Microsoft has issued an update to correct this vulnerability. More details can be found at:

Disclosure Timeline

    2017-03-16 - Vulnerability reported to vendor
    2017-07-11 - Coordinated public release of advisory


This vulnerability was discovered by:
    Tencent Security - Team Sniper (Keen Lab and PC Mgr)