Understanding Rootkits and How do they work?

In this segment, we are going to discuss the Rootkits and how they work.

Breaking into a computer is not simple, so once a Hacker gets in, his first objective is for the most part to ensure that he can get once more into that computer effectively whenever. The best to do this is to control a system administrator account on the computer, other-wise known as a Root account or Root.

To gain and maintain root access, Hackers have made tools called Rootkits, which are programs, or groups of programs, intended to hole through a computer’s protections. That way, if a system administrator finds and blocks the main route the hacker used to get to the computer, the rootkit will have made a few alternate ways for the hacker to get back inside. When a hacker has introduced a Rootkit on a computer he can sneak back in whenever without agonizing over being identified.


Rootkits directly manipulate the operating system, which can be compared to examining the computer’s brain i.e. CPU. To understand how rootkits work, you have to understand how operating systems work.

At the most basic level, an operating system controls all the various parts of a computer. A computer may have a hard disk, memory, a keyboard, and a mouse yet none of this equipment knows how to function with different segments without an operating system.

Older operating systems, for example, MS-DOS, could run just one program at a time, however present-day systems, for example, Linux, Windows, and Mac OS X can run numerous programs at once. So the operating system additionally needs to manage which program gets stacked into memory and which program can utilize the CPU, while it simultaneously checks for input from the keyboard or mouse and sends output to the computer screen.

rootkit, Understanding Rootkits and How do they work?, TechRX
An Operating System prevents applications from directly
accessing the computer’s hardware.

The operating system may likewise stack extra programs called Device Drivers, which are programs that all the operating system how to work with external equipment, for example, a printer or scanner. When a program, for example, a word processor needs to print data, it sends this data to the operating system, which uses the device driver to send it to the printer.

At last, an operating system runs different programs and isolates them so they can’t manipulate the computer’s equipment themselves. Programs, regardless of whether databases or games, send data to the operating system, which at that point saves this data to the hard disk.

Rootkits have been around for yours, perhaps oven longer than viruses and worms. What makes rootkits particularly dangerous is how they’ve managed to evolve. Once a hacker plants a rootkit on a computer, it’s nearly impossible to clean it off the system without reformatting the hard disk and reinstalling the operating system.


Rootkits can delete or modify a computer’s log files. To avoid detection, they try to hide their presence from the eyes of a system administrator. Log files keep track of who used a computer, what they did and for how long they used the computer. This information was particularly crucial when computers were expensive, but equally important, log files could also identify what a computer was doing right before it crashed. When hackers started to invade computers, log files served another purpose. They kept track of when the hacker arrived, what the hacker did and how long the hacker stayed on the computer – much like a surveillance camera which could help the authorities track down the perpetrator.

Therefore, hackers look for the log files that recorded their entry as soon as they gain access to a computer. Among the information a log file might contain that may help a computer’s owner track the hacker down are the following:

– The IP address of the machine that performed an action or request on the target computer.

– The user name, which simply identifies the account being used.

– The date and time of a particular action.

– The exact command or request that the user gave the target computer.

– The number of bytes transferred to the user.

With this information, system administrators can often determine not only when a hacker invaded their symptoms, but can also deduce how the hacker invaded their system.

In many cases, editing the log files can hide a hacker’s tracks, but system administrators have their own techniques for ensuring the integrity of log files which involves printing out the log files as they’re generated. That way, if a hacker does delete or modify the log files at some point, the printed copy will still reveal his or her presence. Another technique is to study the timestamp of the log file. If a hacker modifies the log file, the computer will timestamp the modified log file with the time and date of the modification, which can point to the precise time the hacker was on the computer.


Every program needs a way to communicate with the operating system in order to perform commands such as saving data or sending data to the printer, so operating systems provide a library of functions which is called the Application Programming Interface or API that all programs can use to send commands. To help programmers create and debug her applications, special functions monitor what the operating system is doing at any given time, for example, receiving data from the keyboard or a modem.

Functions that allow another program to peek at the inner workings of an operating system are known as Hooks. Hooks can be handy for writing diagnostic or troubleshooting utilities, but they can also be used by rootkits to subvert the operating system. This is known as hooking.

Rootkits use the same principles to mask their presence on a computer. When a program tries to list all currently running applications, the rootkit hooks into the operating system, intercepts the function call and substitutes another one that reports all currently running applications except the rootkit. Rootkits can use local or global hooks. A local hook intercepts function calls from a specific program, such as an email program. Global hooks intercept function calls from any currently running program.

To guard against rootkit infection, there are programs to monitor and protect the operating system, such as Anti Hook tools.

rootkit, Understanding Rootkits and How do they work?, TechRX
Rootkit can intercept function calls made by applications to OS.

It may be impossible to keep a computer hacker-free. A system administrator may wipe out all rootkits and shut down all backdoors, but there’s still no guarantee that there isn’t something the system administrator may have missed. The only sure way to remove hackers from a computer is by erasing and reinstalling everything from scratch but this is a drastic, time-consuming method. Despite their best efforts, system administrators can’t be perfect, and hackers only need one lucky break to sip into a computer undetected. However, dedicated rootkit detectors help tilt the balance in favor of the system administrators by scanning a computer for signs that betray the existence of a rootkit.

Finally, system administrators need to keep up with the latest security flaws and vulnerabilities so they can patch them or watch out for hackers who may exploit them.

If you have any suggestions or thoughts, just comment down below.


  • rootkit, Understanding Rootkits and How do they work?, TechRX

    My name is Biplab Das. I’m the leader of TechRX and Founder of and Professionally I'm a full-time IT support engineer whose childhood obsession with science fiction never quite faded. A quarter-century later, the technology that I coveted as a kid is woven into the fabric of everyday life. People say smartphones are boring these days, but I think everyone is beginning to take this wonderful technology marvel for granted.

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