CVE-2021-34481: Windows Print Spooler Remote Code Execution Vulnerability

Overview

Severity: High (CVSS 8.8)
CVSS Vector: CVSS:3.0/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H/E:F/RL:O/RC:C
Category: Remote Code Execution
Exploit Status: Not Exploited
Exploitation Likelihood: More Likely
Publicly Disclosed: Yes
Patch Tuesday: 2021-Jul
Released: 2021-07-15
Last Updated: 2021-08-10
EPSS Score: 22.00% (percentile: 95.8%)

Description

A remote code execution vulnerability exists when the Windows Print Spooler service improperly performs privileged file operations. An attacker who successfully exploited this vulnerability could run arbitrary code with SYSTEM privileges. An attacker could then install programs; view, change, or delete data; or create new accounts with full user rights. UPDATE August 10, 2021: Microsoft has completed the investigation and has released security updates to address this vulnerability. Please see the Security Updates table for the applicable update for your system. We recommend that you install these updates immediately. This security update changes the Point and Print default behavior; please see KB5005652.

FAQ

Why did the security impact change from elevation of privilege to remote code execution? We became aware of a remote attack scenario for this vulnerability and revised our assessment accordingly. Did the July 2021 security update introduce this vulnerability? No, the vulnerability existed before the July 13, 2021 security update. We recommend that Microsoft customers install the latest security updates. Why did the Point and Print default behavior change? Please see KB5005652.

Detection & Weaponization (1 sources)

Maturity: Exploit

GitHub PoC: 1 repositories

Affected Products (40)

Windows

Windows 10 Version 1809 for 32-bit Systems
Windows 10 Version 1809 for x64-based Systems
Windows 10 Version 1809 for ARM64-based Systems
Windows Server 2019
Windows Server 2019 (Server Core installation)
Windows 10 Version 1909 for 32-bit Systems
Windows 10 Version 1909 for x64-based Systems
Windows 10 Version 1909 for ARM64-based Systems
Windows 10 Version 21H1 for x64-based Systems
Windows 10 Version 21H1 for ARM64-based Systems
Windows 10 Version 21H1 for 32-bit Systems
Windows 10 Version 2004 for 32-bit Systems
Windows 10 Version 2004 for ARM64-based Systems
Windows 10 Version 2004 for x64-based Systems
Windows Server, version 2004 (Server Core installation)
Windows 10 Version 20H2 for x64-based Systems
Windows 10 Version 20H2 for 32-bit Systems
Windows 10 Version 20H2 for ARM64-based Systems
Windows Server, version 20H2 (Server Core Installation)
Windows 10 for 32-bit Systems
Windows 10 for x64-based Systems
Windows 10 Version 1607 for 32-bit Systems
Windows 10 Version 1607 for x64-based Systems
Windows Server 2016
Windows Server 2016 (Server Core installation)
Windows 8.1 for 32-bit systems
Windows 8.1 for x64-based systems
Windows RT 8.1
Windows Server 2012
Windows Server 2012 (Server Core installation)
Windows Server 2012 R2
Windows Server 2012 R2 (Server Core installation)

ESU

Windows 7 for 32-bit Systems Service Pack 1
Windows 7 for x64-based Systems Service Pack 1
Windows Server 2008 for 32-bit Systems Service Pack 2
Windows Server 2008 for 32-bit Systems Service Pack 2 (Server Core installation)
Windows Server 2008 for x64-based Systems Service Pack 2
Windows Server 2008 for x64-based Systems Service Pack 2 (Server Core installation)
Windows Server 2008 R2 for x64-based Systems Service Pack 1
Windows Server 2008 R2 for x64-based Systems Service Pack 1 (Server Core installation)

Security Updates (13)

Acknowledgments

<a href="https://twitter.com/Junior_Baines">Jacob Baines</a>

Revision History

2021-07-15: Information published.
2021-08-10: CVE updated to announce that Microsoft is releasing security updates for all affected versions of Windows to address this vulnerability. Other information has been updated as well, including the following: 1) Impact has been changed to Remote Code Execution 2) Executive Summary has been updated 3) FAQs have been revised.