9
CVSSv2

CVE-2021-34527

Published: 02/07/2021 Updated: 14/07/2021
CVSS v2 Base Score: 9 | Impact Score: 10 | Exploitability Score: 8
CVSS v3 Base Score: 8.8 | Impact Score: 5.9 | Exploitability Score: 2.8
Vector: AV:N/AC:L/Au:S/C:C/I:C/A:C

Vulnerability Summary

Windows Print Spooler Remote Code Execution Vulnerability (PrintNightmare). 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. An attack must involve an authenticated user calling RpcAddPrinterDriverEx().

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microsoft windows 10 -

microsoft windows 10 20h2

microsoft windows 10 21h1

microsoft windows 10 1607

microsoft windows 10 1809

microsoft windows 10 1909

microsoft windows 10 2004

microsoft windows 7 -

microsoft windows 8.1 -

microsoft windows rt 8.1 -

microsoft windows server 2008 -

microsoft windows server 2008 r2

microsoft windows server 2012 r2

microsoft windows server 2016 -

microsoft windows server 2012 -

microsoft windows server 2019 -

microsoft windows server 2016 2004

microsoft windows server 2016 20h2

Github Repositories

PrinterNightmare-Patcher A fix for PrintNightmare vulnerability that occurs to print spooler service for Windows machines [CVE-2021-34527]

This a scanner for the service Windows-Print-Spooler in risk Based on CVE-2021-34527 PoC originally created by cube0x0

PowerShell Collection of PowerShell scripts I created from May 2021 to Sept 2021 Confirm-PrintNightmareps1: Confirm-PrintNightmare checks to see if the local machine is vulnerable to the PrintNightmare exploit (CVE-2021-34527) as of July 9, 2021, 12:00am The script first checks if the local machine's Print Spooler service is running If the service is running, the scri

PrintNightmare Here is a project that will help to fight against Windows security breach PrintNightmare! (CVE-2021-34527) First of all, On a client, you NEED to update your computer with last microsoft fixs On a server, you HAVE TO switch off then disable at startup the Windows Print Spooler Service via Servicesmsc or via 2 Powershell commands : Stop-Service -Name Spooler -Fo

It Was All A Dream A CVE-2021-34527 (aka PrintNightmare) Python Scanner Allows you to scan entire subnets for the PrintNightmare RCE (not the LPE) and generates a CSV report with the results Tests exploitability over MS-PAR and MS-RPRN This tool has "de-fanged" versions of the Python exploits, it does not actually exploit the hosts however it does use the same vu

CVE-2021-34527 powershell workaround - Disable remote sessions to print spooler without disabling the print spooler service Documented as option 2 under msrcmicrosoftcom/update-guide/vulnerability/CVE-2021-34527 This code is equivallent to setting the 'Allow print spooler to accept client connections' Group Policy setting to 'Disabled' and is inten

disable-RegisterSpoolerRemoteRpcEndPoint Workaround for Windows Print Spooler Remote Code Execution Vulnerability(CVE-2021-34527) See: msrcmicrosoftcom/update-guide/vulnerability/CVE-2021-34527 README is still WIP

Powershell Collection of Powershell scripts I created during my time working from May 2021 to Sept 2021 Confirm-PrintNightmareps1: Confirm-PrintNightmare checks to see if the local machine is vulnerable to the PrintNightmare exploit (CVE-2021-34527) as of July 9, 2021, 12:00am The script first checks if the local machine's Print Spooler service is running If the servic

Disable-Spooler-Service-PrintNightmare-CVE-2021-34527 Simple batch script to disable the Microsoft Print Spooler service from system Run Open the Command and Prompt with elevated privileges, administrative privileges are required to disable the service Run the script \Disable_Spoolerbat

CVE-2021-34527-PrintNightmare-Workaround

printnightmare CVE-2021-34527 implementation

Introduction PrintNightmare-Patcher, a simple tool that resolves the PrintNightmare vulnerability, which occurs to print spooler service for Windows machines [CVE-2021-34527] In addition, it checks if your system has the relevant security update for it or not Installation git clone githubcom/0xirison/PrintNightmare-Patchergit

CVE-2021-34527 - PrintNightmare LPE (PowerShell) Caleb Stewart | John Hammond | June 1, 2021 UPDATE June 2 2021: Microsoft has released an advisory on CVE-2021-34527, correctly terming that specific identifier as the PrintNightmare vulnerability exploit Previously, the community was assuming CVE-2021-1675 "was PrintNightmare" as the June 8 path did not resolve th

Fix-CVE-2021-34527 Fix for the security Script Changes ACL in the directory Stop Service PrintSpooler Spooler Changes StartupType to Disabled

It Was All A Dream A CVE-2021-34527 (aka PrintNightmare) Python Scanner Allows you to scan entire subnets for the PrintNightmare RCE (not the LPE) and generates a CSV report with the results Tests exploitability over MS-PAR and MS-RPRN This tool has "de-fanged" versions of the Python exploits, it does not actually exploit the hosts however it does use the same vu

Printnightmare Fix for PrintNightmare CVE-2021-34527 To Fix Exploit execute as Admin powershellexe -executionpolicy bypass -file \deny-driversps1 To install new Printers execute as Admin powershellexe -executionpolicy bypass -file \allow-driversps1

PrintNightmare_Resolver A fix for PrintNightmare vulnerability that occurs to print spooler service for Windows machines [CVE-2021-34527]

PrintNightMareChecker To check if Spooler is on and whether is it vulnerable to CVE 2021-34527

PowerShell-Scripts Please read the header descriptions and comments in each script body, some contain important instructions or warnings Get-Server_Hosts_txtps1: Provide list of RHOSTS to txt and run script to see if X Service is running on RHOSTS, example use case RHOSTS that have Print Spooler service running for CVE 2021 34527 PRUA Toolkit - Password Reset Account Unlock:

PrintNightmareCheck This repository contains some manul checks to see if the system is vulnerable to the PrintNightmare vulnerability (CVE-2021-1675, CVE-2021-34527) and also a PowerShell script to automate the process Please note that this is the first PowerShell script I have ever written myself so do not rely on it! Manual checks Check if Print Spooler service is running #

PrintNightmare - Windows Print Spooler RCE/LPE Vulnerability (CVE-2021-34527, CVE-2021-1675) Summary This is a remote code execution vulnerability that can be used to obtain SYSTEM level privileges by an authenticated remote user against Windows machines running the print spooler service An attacker could then use that access to create new accounts, attempt to install programs

Printnightmare Safe Tool Windows PrintNightmare vulnerability mitigation tool A tool to start or stop print spooler service with ease for immediate workaround on system flaw Keep spooler service "ON" during use only "DISABLE" service startup CODE BY SRINATH S BHAUMIK Available in "releases" extract all files in one directory execute Runbat A

CVE-2021-34527 - PrintNightmare LPE (PowerShell) Caleb Stewart | John Hammond | June 1, 2021 UPDATE June 2 2021: Microsoft has released an advisory on CVE-2021-34527, correctly terming that specific identifier as the PrintNightmare vulnerability exploit Previously, the community was assuming CVE-2021-1675 "was PrintNightmare" as the June 8 path did not resolve th

CVE-2021-34527 - PrintNightmare LPE (PowerShell) Jennofrie | June 1, 2021 UPDATE June 2 2021: Microsoft has released an advisory on CVE-2021-34527, correctly terming that specific identifier as the PrintNightmare vulnerability exploit Previously, the community was assuming CVE-2021-1675 "was PrintNightmare" as the June 8 path did not resolve this issue This repo

CVE-2021-1675 / CVE-2021-34527 Two mini Script to check if the PrintSpooler Serivce is running within the Forest CVE-2021-1675: msrcmicrosoftcom/update-guide/en-US/vulnerability/CVE-2021-1675 CVE-2021-34527 aka PrintNightmare msrcmicrosoftcom/update-guide/vulnerability/CVE-2021-34527 Scripts Detect running Printer Spooler Service on DCs: githubcom/

Invoke-BuildAnonymousSMBServer Use to build an anonymous SMB file server This is useful for testing CVE-2021-1675 and CVE-2021-34527 Test is successful on the following system: Windows 7 Windows 8 Windows 10 Windows Server 2012 Windows Server 2012 R2 Windows Server 2016

CVE-2021-34527_mitigation Mitigation for CVE-2021-34527 via settings WRITE ACLs - Setting Modify Deny ACLs can cause other issues and is not recommended These scripts are both to add and remove CVE-2021-34527(PrintNightmare) ACL mitigations that I wrote with assistance from /u/AforAnonymous from the reddit thread by Huntress in /r/MSP I've personally tested this using a

PrintNightmare This repo is inteded to help sysadmins to find and mitigate the vulnerability known as "Print Nightmare" PrintNightmareCheck This bash module has the purose to check hosts vulnerable state to CVE-2021-34527 It has some dependencies Just run it and the dependencies will be verified No-Nightmareps1 This powershell module has the purpose to mitigate

random-scripts Just a collection of random scripts nothing much for now nightmaresh scans a subnet for a potential endpoint that is vulnerable to CVE-2021-34527 saves the ip of possible vulnerable host to a file named "reportcsv" NOTE: Use at your own risk as this was only tested on a lab environment

PrintNightmare-Patcher This tool resolves the PrintNightmare vulnerability that occurs to print spooler service for Windows machines [CVE-2021-34527] In addition, it checks if your system has the relevant security update for it or not Usage python printernightmare-patcherpy Installation git clone githubcom/0xIrison/PrintNightmare-Patchergit Dependencies No dependen

Powershell serviceflipper script for Spool service Powershell script to flip the windows spool service on/off to mitigate CVE-2021-34527 Disclaimer I quickly wrote this to mitigate the PrintNightmare thing, so that a user with admin rights can turn on the service on demand quickly It is no solution to the problem and to activate it one needs to lower the powershell security, s

PowerShell-PrintNightmare A collection of scripts to help set the appropriate registry keys for CVE-2021-34527

SharpKatz Porting of mimikatz sekurlsa::logonpasswords, sekurlsa::ekeys and lsadump::dcsync commands Usage Ekeys SharpKatzexe --Command ekeys list Kerberos encryption keys Msv SharpKatzexe --Command msv Retrive user credentials from Msv provider Kerberos SharpKatzexe --Command kerberos Retrive user credentials from Kerberos provider Tspkg SharpKatzexe --Command tspk

PowerSharpPack Many usefull offensive CSharp Projects wraped into Powershell for easy usage Why? In my personal opinion offensive Powershell is not dead because of AMSI, Script-block-logging, Constrained Language Mode or other protection features Any of these mechanisms can be bypassed Since most new innovative offensive security projects are written in C# I decided to make

CVE-2021-1675 / CVE-2021-34527 Impacket implementation of the PrintNightmare PoC originally created by Zhiniang Peng (@edwardzpeng) & Xuefeng Li (@lxf02942370) Tested on a fully patched 2019 Domain Controller Execute malicious DLL's remote or locally Installation Before running the exploit you need to install my version of Impacket and after that you're gucc

Test if you are still vulnerable to PrintNightmare's privesc after patching PrintNightmare (CVE-2021-1675 / CVE 2021 34527) is an exploit that takes advantage of the AddPrintDriver function of the Spooler to arbitrarily execute files with high-privs There is some confusion if the round of patches released by Microsoft on 6th July 2021 It seems the RCE portion of the expl

microsoft-vulnerabilidades Vulnerabilidade de execução remota de código do Spooler de Impressão do Windows CVE-2021-34527 fonte: msrcmicrosoftcom/update-guide/vulnerability/CVE-2021-34527 Vulnerabilidade de Segurança Lançado: 01/07/2021 Last updated: 15 de jul de 2021 Assigning CNA: Microsoft MITRE CVE-2021-34527 CVSS:30 88

PrintNightmare How to disable the Print Spooler service ? CMD Shell net start | findstr -i "spooler" net stop spooler REG ADD "HKLM\SYSTEM\CurrentControlSet\Services\Spooler" /v "Start " /t REG_DWORD /d "4" /f PowerShell Get-Service -Name Spooler Stop-Service -Name Spooler -Force Set-Service -Name Spooler -StartupType Disabled Service Con

PrintNightmare- Information on the Windows Spooler vulnerability - CVE-2021-1675; CVE 2021 34527

CVE-2021-1675 / CVE-2021-34527 Impacket implementation of the PrintNightmare PoC originally created by Zhiniang Peng (@edwardzpeng) & Xuefeng Li (@lxf02942370) Tested on a fully patched 2019 Domain Controller Execute malicious DLL's remote or locally Installation Before running the exploit you need to install my version of Impacket and after that you're gucc

Microsoft Wont-Fix-List A list of vulnerabilities or design flaws Microsoft does not intend to fix Since the number is growing, I decided to make a list LPE = Local Privilege Escalation DPE = Domain-wide Privilege Escalation RCE = Remote Code Execution Vulnerability CVE Attack Type It's NTLM again, right? How it works in a nutshell SpoolSample works as designed

Recent Articles

New Windows print spooler zero day exploitable via remote print servers
BleepingComputer • Lawrence Abrams • 18 Jul 2021

Another zero day vulnerability in Windows Print Spooler can give a threat actor administrative privileges on a Windows machine through a remote server under the attacker's control and the 'Queue-Specific Files' feature.
Last month, a security researcher accidentally revealed a zero-day Windows print spooler vulnerability known as 
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Microsoft: New Unpatched Bug in Windows Print Spooler
Threatpost • Elizabeth Montalbano • 16 Jul 2021

Microsoft has warned of yet another vulnerability that’s been discovered in its Windows Print Spooler that can allow attackers to elevate privilege to gain full user rights to a system. The advisory comes on the heels of patching two other remote code-execution (RCE) bugs found in the print service that collectively became known as PrintNightmare.
The company released the advisory late Thursday for the latest bug, a Windows Print Spooler elevation-of-privilege vulnerability tracked as CV...

You'll want to shut down the Windows Print Spooler service (yes, again): Another privilege escalation bug found
The Register • Richard Speed • 16 Jul 2021

PrintNightmare? More like Groundhog Day for admins

Microsoft has shared guidance revealing yet another vulnerability connected to its Windows Print Spooler service, saying it is "developing a security update."
The latest Print Spooler service vuln has been assigned CVE-2021-34481, and can be exploited to elevate privilege to SYSTEM level via file operations.
This can be used by malware already running on a Windows machine or a rogue user to fully compromise a bo
The solution? For now, you can only "stop and disable the Print Sp...

Microsoft Defender for Identity now detects PrintNightmare attacks
BleepingComputer • Sergiu Gatlan • 16 Jul 2021

Microsoft has added support for PrintNightmare exploitation detection to Microsoft Defender for Identity to help Security Operations teams detect attackers' attempts to abuse this critical vulnerability.
As revealed by Microsoft program manager
, Defender for Identity
 Windows Print Spooler service exploitation (including the actively exploited CVE-2021-34527 
 bug) and helps block lateral movement attempts within an org's network.
If successfully exploit...

Microsoft's print nightmare continues with malicious driver packages
BleepingComputer • Lawrence Abrams • 15 Jul 2021

Microsoft's print nightmare continues with another example of how a threat actor can achieve SYSTEM privileges by abusing malicious printer drivers.
Last month, security researchers accidentally disclosed a proof-of-concept exploit for the 
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This vulnerability is tracked as CVE-2021-34527 and is a missing permission check in the Windows Print Spooler that allows for installing malicious print drivers to achieve remote code execution or local privilege escalation on vulnerable...

Windows print nightmare continues with malicious driver packages
BleepingComputer • Lawrence Abrams • 15 Jul 2021

Microsoft's print nightmare continues with another example of how a threat actor can achieve SYSTEM privileges by abusing malicious printer drivers.
Last month, security researchers accidentally disclosed a proof-of-concept exploit for the 
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This vulnerability is tracked as CVE-2021-34527 and is a missing permission check in the Windows Print Spooler that allows for installing malicious print drivers to achieve remote code execution or local privilege escalation on vulnerable...

Microsoft Patch Tuesday fixes 13 critical flaws, including 4 under active attack
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The second Tuesday of the month is here, which means that Microsoft has rolled out patches for security vulnerabilities in Windows and its other products as part of its monthly Patch Tuesday bundle. This month’s batch of security updates brings fixes for no fewer than 117 security vulnerabilities including four security loopholes that are being actively exploited in the wild according to Microsoft.
Of the grand total, 13 security flaws have received the highest severity rating of “cr...

Microsoft Crushes 116 Bugs, Three Actively Exploited
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Three bugs under active exploit were squashed by Microsoft Tuesday, part of its July security roundup of fixes for Windows, Microsoft Office, SharePoint Server and Exchange Server. In all, Microsoft patched 116 bugs. Twelve bugs are rated critical, 103 rated important and one classified as moderate in severity.
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CISA orders federal agencies to patch Windows PrintNightmare bug
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A new emergency directive ordered by the Cybersecurity and Infrastructure Security Agency (CISA) orders federal agencies to mitigate an actively exploited vulnerability in Pulse Connect Secure (PCS) VPN appliances on their networks by Friday.
CISA issued the Emergency Directive 21-04 after
 on Friday to address an actively exploited Print Spooler vulnerability dubbed
 in all supported Windows versions.
The security vulnerability (tracked as CVE-2021-34527) enable...

Microsoft issues patch to fix PrintNightmare zero‑day bug
welivesecurity • 08 Jul 2021

Microsoft on Wednesday released an emergency update to plug a vulnerability in  the Windows Print Spooler service that is being actively exploited in the wild. Dubbed PrintNightmare, the zero-day security flaw affects all versions of the Microsoft Windows operating system going back as far as Windows 7.
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Microsoft struggles to wake from its PrintNightmare: Latest print spooler patch can be bypassed, researchers say
The Register • Richard Speed • 07 Jul 2021

I pity the spool

Any celebrations that Microsoft's out-of-band patch had put a stop PrintNightmare shenanigans may have been premature.
The emergency update turned up yesterday for a variety of Microsoft operating systems; little-used products like Windows Server 2012 and 2016 were excluded from the interim release.
While it initially appeared the remote-code execution (RCE) aspect of the security bug had been resolved, the local privilege escalation (LPE) hole remained, judging by the findings of a ...

Microsoft patches PrintNightmare — even on Windows 7 — but the terror isn’t over
The Register • Simon Sharwood, APAC Editor • 07 Jul 2021

No fixes yet for Windows 10 version 1607, Windows Server 2016, or Windows Server 2012

Microsoft has issued out-of-band patches for the PrintNightmare print spooler bug that allows lets remote Windows users execute code as system on your domain controller.
The bug, designated CVE-2021-34527, is present in all versions of Windows.
However, Microsoft’s advisory states: “Updates are not yet available for Windows 10 version 1607, Windows Server 2016, or Windows Server 2012.”
Those are worrying omissions, as the first two versions mentioned are five years old an...

How to mitigate Print Spooler vulnerability on Windows 10
BleepingComputer • Mayank Parmar • 07 Jul 2021

Yesterday,
to fix the widely reported "
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According to Microsoft, this vulnerability is impacting all Windows 10 versions, including the most recent May 2021 Update (version 21H1) and version 20H2 (October 2020 Update).
To deploy Microsoft's patch, you need to check for updates under Updates & Security > Windows Update and apply the latest July update, and reboot the system when prompted.
Alternatively, y...

CISA Offers New Mitigation for PrintNightmare Bug
Threatpost • Elizabeth Montalbano • 02 Jul 2021

The U.S. government has stepped in to offer a mitigation for a critical remote code execution (RCE) vulnerability in the Windows Print Spooler service that may not have been fully patched by Microsoft’s initial effort to fix it.
To mitigate the bug, dubbed PrintNightmare, the CERT Coordination Center (CERT/CC) has released a VulNote for CVE-2021-1675 urging system administrations to disable the Windows Print Spooler service in Domain Controllers and systems that do not print, the Cyberse...

Microsoft shares mitigations for Windows PrintNightmare zero-day bug
BleepingComputer • Sergiu Gatlan • 02 Jul 2021

Microsoft has provided mitigation guidance to block attacks on systems vulnerable to exploits targeting the Windows Print Spooler zero-day vulnerability known as PrintNightmare.
This remote code execution (RCE) bug—now tracked as CVE-2021-34527—impacts all versions of Windows per Microsoft, with the company still investigating if the vulnerability is exploitable on all of them.
CVE-2021-34527 allows 
 via remote code execution with SYSTEM privileges as it enables them ...

The PrintNightmare continues: Microsoft confirms presence of vulnerable code in all versions of Windows
The Register • Richard Speed • 02 Jul 2021

That printer plugged into your domain controller? Yeah, you might not be using that for a while

Microsoft has assigned CVE-2021-34527 to the print spooler remote code execution vulnerability known as "PrintNightmare" and confirmed that the offending code is lurking in all versions of Windows.
The megacorp said it was still investigating whether the vulnerability was exploitable in every version, but domain controllers are indeed affected.
Microsoft also confirmed that this nasty was distinct from CVE-2021-1675, which was all about a different attack vector and a different vulne...

Actively exploited PrintNightmare zero-day gets unofficial patch
BleepingComputer • Sergiu Gatlan • 02 Jul 2021

Free micropatches addressing the actively exploited PrintNightmare zero-day vulnerability in the Windows Print Spooler service are now available through the 0patch platform.
The buggy code behind this remote code execution bug (tracked as CVE-2021-34527) is present in all versions of Windows, with Microsoft still investigating if the vulnerability can be exploited exploitable on all of them.
CVE-2021-34527 enables
via RCE with SYSTEM privileges, allowing them to install progr...

Microsoft: PrintNightmare now patched on all Windows versions
BleepingComputer • Sergiu Gatlan • 01 Jan 1970

Microsoft has released the KB5004948 emergency security update to address the Windows Print Spooler PrintNightmare vulnerability on all editions of Windows 10 1607 and Windows Server 2016.
"An update has now been released for all affected versions of Windows that are still in support," Microsoft
in the Windows message center.
The
 bug tracked as CVE-2021-34527 enables 
 via remote code execution (RCE) with SYSTEM privileges.
Detailed steps on how to ins...

Microsoft pushes emergency update for Windows PrintNightmare zero-day
BleepingComputer • Sergiu Gatlan • 01 Jan 1970

Microsoft has released the KB5004945 emergency security update to address the actively exploited PrintNightmare zero-day vulnerability in the Windows Print Spooler service impacting all Windows versions.
The remote code execution bug (tracked as CVE-2021-34527) allows 
 via remote code execution (RCE) with SYSTEM privileges, as it will enable them to install programs, view, change, or delete data, and create new accounts with full user rights.
Detailed instructions on how to ...

Microsoft pushes emergency fix for Windows PrintNightmare vulnerability
BleepingComputer • Sergiu Gatlan • 01 Jan 1970

Microsoft has released the KB5004945 emergency security update to fix the actively exploited PrintNightmare zero-day vulnerability in the Windows Print Spooler service impacting all Windows versions. However, the patch is incomplete and the vulnerability can still be locally exploited to gain SYSTEM privileges.
The remote code execution bug (tracked as CVE-2021-34527) allows 
 via remote code execution (RCE) with SYSTEM privileges, as it will enable them to install programs, view, ...