Some malware embeds itself in the kernel of your operating system. In this video, you’ll learn about rootkits and how to find and remove this dangerous malware.
The term “rootkit” has a foundation in Unix or Linux, where root is the administrative account on that particular system. But rootkits can be found on any operating system, Windows, Linux, Mac OS, and anything else. A common characteristic of a rootkit is, instead of modifying files in your operating system, it’s modifying files in the kernel of the operating system. These are the foundational building blocks of the operating system. And everything that runs in the OS runs on top of that kernel.
Because this malware now becomes part of the operating system itself, it effectively becomes invisible to antivirus and anti-malware software. And that’s one of the reasons why identifying and removing a rootkit from a system can be a very difficult process.
Malware authors were starting to combine rootkit functionality with their malware functionality to create a botnet that would be very difficult to remove from a system. A good example of malware that was starting to combine a rootkit with the malware itself was the Zeus, or the Zbot malware. This was malware that was very good at transferring money out of your bank account and into the bank account of the malware author.
They combined the Zeus malware with the Necurs rootkit. This created a type of malware that, once it was installed, it made it almost impossible to delete it from your system. Any time you would try to delete the files, the rootkit would be part of the operating system and would prevent you from deleting any part of the botnet malware. If you tried to stop the Windows process the malware was using, the access would also be denied. Anything that you tried to do to stop that malware from running would be stopped by the underlying rootkit in the operating system.
There are some anti-malware and antivirus software that can look for and identify rootkits that may be running on a system. And there are specific rootkit removers that are designed to remove specific variants or specific types of rootkits. Fortunately, we’ve created new types of BIOS software such as the UEFI BIOS that includes a feature called secure boot. This secure boot feature will look to see if any part of the kernel has been changed. And it will not boot a system that may have been modified, thereby preventing rootkits from being installed on our modern systems.