The security of Linux servers is of paramount importance in today’s digital environment where cyber threats are constantly evolving. One such critical vulnerability requiring immediate action is the PwnKit vulnerability, identified as CVE-2021-4034.
Let’s examine the nature of this vulnerability, its potential impact on Linux servers, and most importantly, ways to effectively patch and secure your Linux server against this threat.
What Is PwnKit Vulnerability CVE-2021-4034?
The PwnKit vulnerability (CVE-2021-4034)is a critical vulnerability that affects Linux servers, especially those running outdated kernel versions.
Due to this vulnerability, malicious actors can execute arbitrary code on Linux devices and gain unauthorized access to the system. Of course, this leads to potential data breaches and service disruptions.
What Precautions Should You Take?
The first line of defense against potential threats is to ensure that your Linux server is regularly updated with the latest security patches.
Keeping your system up-to-date is one of the biggest steps you can take to close known vulnerabilities and prevent cyber attackers from exploiting them.
If you have problemsupdating your kernel, you’re able to use a workaround. This requires you to do a little manipulation forpkexec. The main purpose of this process will be to make an authorization arrangement in theSUIDroot program called pkexec.
SUID allows normal users to perform certain operations and files with privileges that only the root user can do. So basically, if you block the use of pkexec by a malicious person, you will get rid of this security vulnerability.
To do this, first, make sure you have updated your system:
On Arch Linux:
On Fedora and RHEL:
Then you need tochange the users' privilegesto remove the SUID in pkexec. All you need to do is run the following command:
This method will provide a temporary solution. For truly strong protection, you should not fail your updates.
How Do I Protect Servers From Linux Kernel Vulnerabilities?
Keeping your Linux kernel up to date is one of the most effective ways to protect yourself against known vulnerabilities. Major Linux distributions release security patches and updates to immediately fix identified vulnerabilities. So check for updates regularly and apply them without delay.
It is also necessary to configure a strong firewall and access control mechanisms to minimize the risk of unauthorized access and exploitation of core vulnerabilities. By diligently applying security updates and using robust access controls, you can significantly increase the security of your Linux kernel and protect your system from potential vulnerabilities.
Regularly monitoring security advisories and staying informed about the latest threats will also ensure that you take timely action to strengthen your system’s defenses against emerging risks.
