CVE-2021-34527
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 July 7, 2021: The security update for Windows Server 2012, Windows Server 2016 and Windows 10, Version 1607 have been released. Please see the Security Updates table for the applicable update for your system. We recommend that you install these updates immediately. If you are unable to install these updates, see the FAQ and Workaround sections in this CVE for information on how to help protect your system from this vulnerability. In addition to installing the updates, in order to secure your system, you must confirm that the following registry settings are set to 0 (zero) or are not defined (Note: These registry keys do not exist by default, and therefore are already at the secure setting.), also that your Group Policy setting are correct (see FAQ): HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Microsoft\Windows NT\Printers\PointAndPrint NoWarningNoElevationOnInstall = 0 (DWORD) or not defined (default setting) UpdatePromptSettings = 0 (DWORD) or not defined (default setting) Having NoWarningNoElevationOnInstall set to 1 makes your system vulnerable by design. UPDATE July 6, 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. If you are unable to install these updates, see the FAQ and Workaround sections in this CVE for information on how to help protect your system from this vulnerability. See also KB5005010: Restricting installation of new printer drivers after applying the July 6, 2021 updates. Note that the security updates released on and after July 6, 2021 contain protections for CVE-2021-1675 and the additional remote code execution exploit in the Windows Print Spooler service known as “PrintNightmare”, documented in CVE-2021-34527.
How to fix
Apply updates per vendor instructions.
CISA due date: May 3, 2022- microsoft windows_10_150710.0.10240.18969 or later
- microsoft windows_10_160710.0.14393.4470 or later
- microsoft windows_10_180910.0.17763.2029 or later
- microsoft windows_10_20h210.0.19042.1083 or later
- microsoft windows_10_21h210.0.19044.1415 or later
- microsoft windows_10_22h210.0.19045.2251 or later
- microsoft windows_11_21h210.0.22000.318 or later
- microsoft windows_11_22h210.0.22621.674 or later
- microsoft windows_server_201610.0.14393.4470 or later
- microsoft windows_server_201910.0.17763.2029 or later
- microsoft windows_server_202210.0.20348.230 or later
- microsoft windows_server_20h210.0.19042.1083 or later
Affected products
| Product | Affected versions | Fixed in |
|---|---|---|
| microsoft windows_10_1507 | v < 10.0.10240.18969 | 10.0.10240.18969 |
| microsoft windows_10_1607 | v < 10.0.14393.4470 | 10.0.14393.4470 |
| microsoft windows_10_1809 | v < 10.0.17763.2029 | 10.0.17763.2029 |
| microsoft windows_10_20h2 | v < 10.0.19042.1083 | 10.0.19042.1083 |
| microsoft windows_10_21h2 | v < 10.0.19044.1415 | 10.0.19044.1415 |
| microsoft windows_10_22h2 | v < 10.0.19045.2251 | 10.0.19045.2251 |
| microsoft windows_11_21h2 | v < 10.0.22000.318 | 10.0.22000.318 |
| microsoft windows_11_22h2 | v < 10.0.22621.674 | 10.0.22621.674 |
| microsoft windows_rt_8.1 | No range specified | — |
| microsoft windows_server_2008 | No range specified, r2 | — |
| microsoft windows_server_2012 | No range specified, r2 | — |
| microsoft windows_server_2016 | v < 10.0.14393.4470 | 10.0.14393.4470 |
| microsoft windows_server_2019 | v < 10.0.17763.2029 | 10.0.17763.2029 |
| microsoft windows_server_2022 | v < 10.0.20348.230 | 10.0.20348.230 |
| microsoft windows_server_20h2 | v < 10.0.19042.1083 | 10.0.19042.1083 |
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