Microsoft issues an out-of-band patch for critical ‘PrintNightmare’ vulnerability following reports of in-the-wild exploitation and publication of multiple proof-of-concept exploit scripts Update July 9, 2021: The Solution section has been updated to clarify the vulnerable configurations as well as a mitigation to ensure exploitation is not feasible post-patch

CVE-2021-34527: Microsoft Releases Out-of-Band Patch for PrintNightmare Vulnerability in Windows Print Spooler

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): <ul> <li>HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Microsoft\Windows NT\Printers\PointAndPrint</li> <li>NoWarningNoElevationOnInstall = 0 (DWORD) or not defined (default setting)</li> <li>UpdatePromptSettings = 0 (DWORD) or not defined (default setting)</li> </ul> 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 <a href="https://support.microsoft.com/topic/31b91c02-05bc-4ada-a7ea-183b129578a7">KB5005010: Restricting installation of new printer drivers after applying the July 6, 2021 updates</a>. 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.

The remote Windows host is missing security update 5008212.
It is, therefore, affected by multiple vulnerabilities:

  - An elevation of privilege vulnerability. An attacker can     exploit this to gain elevated privileges.
    (CVE-2021-41333, CVE-2021-43207, CVE-2021-43223,     CVE-2021-43226, CVE-2021-43229, CVE-2021-43230,     CVE-2021-43231, CVE-2021-43237, CVE-2021-43238,     CVE-2021-43239, CVE-2021-43240, CVE-2021-43247,     CVE-2021-43248, CVE-2021-43883, CVE-2021-43893)

  - A remote code execution vulnerability. An attacker can     exploit this to bypass authentication and execute     unauthorized arbitrary commands. (CVE-2021-43215,     CVE-2021-43217, CVE-2021-43232, CVE-2021-43233,     CVE-2021-43234)

  - An information disclosure vulnerability. An attacker can     exploit this to disclose potentially sensitive     information. (CVE-2021-43216, CVE-2021-43222,     CVE-2021-43224, CVE-2021-43227, CVE-2021-43235,     CVE-2021-43236, CVE-2021-43244)

  - A denial of service (DoS) vulnerability. An attacker can     exploit this issue to cause the affected component to     deny system or application services. (CVE-2021-43219,     CVE-2021-43228, CVE-2021-43246)

The Windows 11 installation on the remote host is missing security updates. It is, therefore, affected by multiple vulnerabilities:

  - A denial of service (DoS) vulnerability. An attacker can     exploit this issue to cause the affected component to     deny system or application services. (CVE-2021-41356,     CVE-2021-42274, CVE-2021-42284)

  - A remote code execution vulnerability. An attacker can     exploit this to bypass authentication and execute     unauthorized arbitrary commands. (CVE-2021-26443,     CVE-2021-38666, CVE-2021-41378, CVE-2021-42276,     CVE-2021-42279)

  - An elevation of privilege vulnerability. An attacker can     exploit this to gain elevated privileges.
    (CVE-2021-36957, CVE-2021-41366, CVE-2021-41367,     CVE-2021-41370, CVE-2021-41377, CVE-2021-41379,     CVE-2021-42277, CVE-2021-42280, CVE-2021-42283,     CVE-2021-42285)

  - An information disclosure vulnerability. An attacker can     exploit this to disclose potentially sensitive     information. (CVE-2021-38631, CVE-2021-38665,     CVE-2021-41371)

A remote command execution vulnerability exists in Windows Print Spooler service improperly performs privileged file   operations. An authenticated, remote attacker can exploit this to bypass and run arbitrary code with SYSTEM privileges.     The remote system is not fully secure as the point and print registry settings contain an insecure configuration in   one of the following locations/keys:

    - HKLM\SOFTWARE\Policies\Microsoft\Windows NT\Printers\PointAndPrint
    - HKLM\SOFTWARE\Policies\Microsoft\Windows NT\Printers\PointAndPrint\NoWarningNoElevationOnInstall
    - HKLM\SOFTWARE\Policies\Microsoft\Windows NT\Printers\PointAndPrint\UpdatePromptSettings

A remote command execution vulnerability exists in Windows Print Spooler service improperly performs privileged file operations. An authenticated, remote attacker can exploit this to bypass and run arbitrary code with SYSTEM privileges.

A remote command execution vulnerability exists in Windows Print Spooler service improperly performs privileged file   operations. An authenticated, remote attacker can exploit this to bypass and run arbitrary code with SYSTEM privileges.

ID	Name	Product	Family	Severity
156065	KB5008212: Windows 10 Version 2004 / Windows 10 Version 20H2 / Windows 10 Version 21H1 / Windows 10 Version 21H2 Security Update (December 2021)	Nessus	Windows : Microsoft Bulletins	critical
154997	KB5007215: Windows 11 Security Updates (November 2021)	Nessus	Windows : Microsoft Bulletins	critical
151488	Windows PrintNightmare Registry Exposure CVE-2021-34527 OOB Security Update RCE (July 2021)	Nessus	Windows : Microsoft Bulletins	high
151479	KB5004960: Windows Server 2012 OOB Security Update RCE (July 2021)	Nessus	Windows : Microsoft Bulletins	high
151478	KB5004959: Windows Server 2008 OOB Security Update RCE (July 2021)	Nessus	Windows : Microsoft Bulletins	high
151477	KB5004958: Windows Server 2012 R2 OOB Security Update RCE (July 2021)	Nessus	Windows : Microsoft Bulletins	high
151476	KB5004951: Windows 7 and Windows Server 2008 R2 OOB Security Update RCE (July 2021)	Nessus	Windows : Microsoft Bulletins	high
151475	KB5004950: Windows 10 1507 LTS OOB Security Update RCE (July 2021)	Nessus	Windows : Microsoft Bulletins	high
151474	KB5004948: Windows 10 1607 and Windows Server 2016 OOB Security Update RCE (July 2021)	Nessus	Windows : Microsoft Bulletins	high
151473	KB5004947: Windows 10 1809 and Windows Server 2019 OOB Security Update RCE (July 2021)	Nessus	Windows : Microsoft Bulletins	high
151472	KB5004946: Windows 10 1909 OOB Security Update RCE (July 2021)	Nessus	Windows : Microsoft Bulletins	high
151471	KB5004945: Windows 10 2004 / 20H2 / 21H1 OOB Security Update RCE (July 2021)	Nessus	Windows : Microsoft Bulletins	high

Detections

Analytics

CVE-2021-34527

high

Tenable Plugins

critical

critical

high

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high

high

high

high

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high