Malware comes in many forms, but kernel-level malware is among the most dangerous. What makes it so threatening, and how can you defend against it? Let’s explore the details below.
What Is Kernel-Level Malware?
The kernel is the core component of an operating system, responsible for managing all interactions between hardware and software. It operates at an elevated privilege level known as “kernel mode,” which gives it unrestricted access to all system resources, including memory, CPU, and connected devices. The malware that infects and manipulates this privileged level is known as kernel-level malware.
Such malware exploits the high privileges of the kernel, enabling it to execute malicious activities with minimal detection. By operating at this low level, it can evade security measures, persist, and gain control over critical system operations.
Below are some common examples of kernel-level malware:
Kernel rootkits: this is among the most notorious forms of kernel-level malware that grants an attacker undetected remote control of a computer. This access allows them to compromise security, install more malware, monitor activity, or use the device in DDoS attacks.
Bootkits: it’s a type of rootkit that infects PC BIOS or Master Boot Record (MBR) to load malicious code before the operating system is loaded. They can install kernel-level malicious code and persist through reboots and reinstalls of the OS.
Kernel-mode trojans: with higher privileges, these trojans can effectively evade detection by replacing processes or embedding themselves within other processes. They’re typically designed for specific tasks, such as recording keystrokes, disabling security measures, and modifying system files.
Kernel-level ransomware: this type of ransomware uses kernel privileges to encrypt data or prevent users from accessing the system. It can bypass security more efficiently and make recovery difficult.
How to Protect Against Kernel-Level Malware
Fortunately, it’s quite challenging for kernel-level malware to infect your PC. This type of malware requires elevated permissions that the operating system doesn’t grant to unauthorized programs. Therefore, kernel-level malware typically relies on exploiting known vulnerabilities or gaining physical or remote access to an administrator account.
PC security systems are designed to detect and prevent kernel-level malware attacks. Even if someone attempts to install such malware intentionally, the operating system’s security mechanisms will likely block the installation.
However, you still need security features enabled on your PC to minimize vulnerabilities and detect attacks promptly. Follow the steps below to defend against kernel-level malware:
Ensure Secure Boot and TPM 2.0 Are Enabled
Secure Boot and TPM 2.0 (Trusted Platform Module) are essential security features in Windows and are crucial for defending against kernel-level malware. This is why they are also required for Windows 11 installation.
Secure Boot checks the digital signature of all software during startup, blocking any unverified software from running.
TPM 2.0 is a physical security chip that stores cryptographic hashes of the boot process. It detects any tampering by comparing these hashes at every startup and alerts users if it finds changes.
To check whether Secure Boot is enabled, search for “system information” in Windows Search, and open the System Information app. You’ll find the Secure Boot State value in the System Summary. Make sure it’s set to On.
To ensure TPM 2.0 is enabled (or supported), press Windows + R, and type tpm.msc in the Run dialog.
Ensure the Status section says The TPM is ready for use and the Specification Version is set to 2.0.
If any of these are disabled, access BIOS/UEFI, and enable the value under the Security category. Enabling Secure Boot should be simple, but TMP 2.0 is a hardware chip that your PC may not have.
Enable Virtualization-Based Security in Windows
Virtualization-based security (VBS) uses hardware virtualization to run critical system processes in an isolated environment to prevent malicious apps from tampering with them. Since kernel-level malware often takes advantage of vulnerabilities in critical system processes, this feature will protect them.
In Windows Search, type “windows security,” and open the Windows Security app. Move to Device Security -> Core isolation, and ensure Memory integrity is turned On.
Set User Account Control (UAC) to Maximum Security
UAC protects your PC by preventing apps from installing or making changes to your PC without your permission. You can set it to maximum security so that Windows always asks your permission when you or any app tries to install something or change a setting.
Search for “uac” in Windows Search, and click on Change User Account Control settings. Set the slider here to Always notify at the very top.
Keep PC Up to Date
As mentioned earlier, kernel-level malware often takes advantage of vulnerabilities to infect the PC. Keeping your system up to date ensures timely patching of known vulnerabilities, preventing malicious programs from exploiting them.
Ensure that you update Windows, drivers, and BIOS/UEFI to the latest versions.
Windows: to update Windows, go to Windows Update in Windows Settings, and click on Check for updates. If it says You’re up to date, everything is fine. Otherwise, download and install the recommended updates.
Drivers: these are the most vulnerable, as they load during the boot process, and a compromised driver can enable infection at the kernel level. You can use a driver updater tool like iObit Driver Booster to automatically update all drivers.
BIOS/UEFI: it’s a bit difficult to update BIOS/UEFI, as you need to manually do it, but thankfully, these updates are rare.
Use Standard User Account for Daily Use
The standard user account has restricted access to many functions, but it’s good enough for day-to-day use. As it’s restricted, it also limits kernel-malware’s ability to infect the device.
To create a standard account, open Windows Settings, and go to Accounts -> Other Users. Click on Add account to create a new account, and make sure you select Standard account instead of Administrator.
Occasionally Run Boot-Time Scan
The boot-time scan is a standard function in most antivirus software, including Microsoft Defender. This scan restarts your PC and scans it before the operating system fully loads. This is very effective against kernel-level malware, as it can detect them before they try to hide from the operating system. Occasionally, run it to make sure your PC is clean.
To run this scan in Windows, search for “windows security” in Windows Search, and open the Windows Security app.
Move to Virus & threat protection -> Scan options, and select Microsoft Defender Antivirus (offline scan). When you click on Scan now, it will prompt you to restart the PC for the scan.
Avoid Executing Risky Programs
This is general advice to avoid all types of system security risks, but it’s especially important when it comes to kernel-level malware. It can’t access the kernel without disabling the operating system’s security features. This means kernel-level malware will give clear red flags, such as asking you to disable security features to run the app.
Be cautious about downloading suspicious software, like video game hacks or pirated premium programs. If an app requires you to disable specific security protections, the potential risk likely outweighs any benefits it would offer.
What to Do if Your PC Gets Infected
Unusually high CPU usage, freezes, crashes (BSOD), and suspicious network activity are common signs of kernel-level malware infection. If you think your PC is infected, you need to act immediately. Unfortunately, you have limited options, as the malware can be very sticky.
Use Antivirus Software with Rootkit Removal Feature
Most antivirus software with rootkit removal features can remove most types of kernel-level malware. We recommend Malwarebytes, as it has a dedicated rootkit removal feature that is very effective.
You’ll have to enable the rootkit scan function first, as it’s disabled by default. Click on Settings in Malwarebytes, then move to the Scan and detection section. Enable the Scan for rootkits option.
Your next scan will also include the rootkit scanning function that could find the kernel-level malware infecting your PC.
Run Boot-Time Scan
As mentioned above, a boot-time scan can detect kernel-level malware that depends on hiding itself before the boot process. You can either run the Microsoft Defender scan as we did above, or use a third-party app. Avast One has a powerful boot-time scan functionality that you can try if Microsoft Defender fails.
Reinstall Windows
If security software is unable to catch kernel-level malware, reinstalling Windows should fix the issue. You should do a fresh install, as the current image could be infected. There are multiple ways to install Windows 11, so choose your preferred method.
Overall, kernel-level malware can be extremely dangerous, but it’s difficult for hackers to get it into your device. If you are having trouble getting rid of kernel-level malware, upgrading/reinstalling the BIOS can fix the problem. You can also take it to a professional to reflash BIOS and clear CMOS.
Image credit: Freepik. All screenshots by Karrar Haider.
Our latest tutorials delivered straight to your inbox
