👉 Overview
👀 What ?
Windows PrintNightmare is a critical security vulnerability discovered in the Windows Print Spooler service. It allows attackers to execute arbitrary code with system-level privileges, leading to a full system compromise. This vulnerability is identified as CVE-2021-1675 and CVE-2021-34527.
🧐 Why ?
Understanding Windows PrintNightmare is important due to its severity and widespread impact. It affects all versions of Windows, and if exploited, it can lead to a full system compromise. Therefore, it's crucial for system administrators and cybersecurity professionals to understand this vulnerability to mitigate risks and protect their systems.
⛏️ How ?
To mitigate the PrintNightmare vulnerability, Microsoft released security updates that should be applied immediately. For systems where the update can't be applied, some workarounds include disabling the Print Spooler service or disabling inbound remote printing through Group Policy. Regularly updating your systems and following cybersecurity best practices can help prevent exploitation of such vulnerabilities.
⏳ When ?
The PrintNightmare vulnerability was first reported in June 2021. Despite Microsoft's initial patch, the vulnerability was still exploitable, leading to the release of an updated patch in July 2021.
⚙️ Technical Explanations
PrintNightmare, formally known as CVE-2021-1675 and CVE-2021-34527, is a critical security vulnerability found in the Windows Print Spooler service that has far-reaching implications. This service is an integral component of the Windows operating system and is responsible for managing all print jobs sent to the computer printer or print server.
The crux of the vulnerability is that the Print Spooler service incorrectly performs privileged file operations. This means it doesn't properly check and manage the files and data it's handling, thus creating a potential loophole for exploitation. It can be exploited by attackers who run specially designed programs that manipulate this flaw, enabling them to execute code with system-level privileges.
The system-level privileges mean that the attacker's code runs with the highest level of access, providing them with the ability to perform any action on the system. This includes creating new accounts with full user rights, installing programs, and viewing, changing, or deleting data.
Given the severity of the potential impact, it's crucial that system administrators and cybersecurity professionals understand and address this vulnerability promptly. Microsoft has released security updates to mitigate the vulnerability, and these updates should be applied immediately. If the update cannot be applied for any reason, potential workarounds include disabling the Print Spooler service or disabling inbound remote printing through Group Policy to limit the potential attack surface.
It's worth noting that the PrintNightmare vulnerability came to light in June 2021. Despite an initial patch from Microsoft, the vulnerability remained exploitable. This led to the release of an updated patch in July 2021 to address the ongoing security issue. As with all cybersecurity matters, regularly updating systems and adhering to cybersecurity best practices are crucial in preventing the exploitation of such vulnerabilities.
Let's walk through an example of how to apply the Microsoft security update to mitigate the PrintNightmare vulnerability:
- Check your current system version: To know which update you need to download, you first need to check your Windows version. You can do this by typing
winverin the search bar and pressing enter. A window will open showing the version of your operating system. - Download the correct update: Go to the Microsoft Update Catalog website. In the search bar, type the KB number of the update that corresponds to your version of Windows, which you can find in Microsoft's official documentation for the PrintNightmare vulnerability.
- Install the update: Once downloaded, double click the update file and follow the prompts to install it.
- Restart your computer: After the installation is complete, you'll need to restart your computer for the changes to take effect.
In case you are unable to apply the update, you can mitigate the vulnerability by disabling the Print Spooler service. Here's how:
- Open the Command Prompt: Type
cmdin the search bar and select 'Run as administrator'. - Disable the Print Spooler: In the Command Prompt, type
net stop spoolerand press enter. This stops the Print Spooler service. To disable it so it doesn't start again with your next reboot, typesc config spooler start= disabledand press enter.
Remember, these steps only mitigate the vulnerability. Keeping your systems updated is the best way to ensure their security.