Is malware hiding on your computer and giving hackers access? It could be a barely detectable sliver of software called a rootkit. Read on to explore the different members of this nasty app family, including how to detect and remove them—and stay safer online with Avira Internet Security. It contains trusted anti-malware to help protect you from rootkits and more. It helps fix software vulnerabilities and can block web trackers.
What is a rootkit and why do hackers love it?
Welcome to the special agents of the malware world: rootkits. They’re a clandestine group of computer programs designed to sneakily enter and hide in your machine. Here they ‘live’ safely concealed from users and system processes while they grant hackers privileged access to the targeted device. The name is a blend of two words that summarise this malware’s intentions. In Unix and Linux operating systems the most privileged account admin is called the “root”, while “kit” refers to the software components that allow unauthorised admin-level access. In other words, rootkits are tools that provide privileged access to the heart or ‘root’ of a system.
Once rootkits have embedded themselves in a system, they open a virtual backdoor to cyber-attackers who can then log in remotely to carry out any number of malicious actions. Usually on the hacker agenda is: stealing personal or financial data, destroying system files, installing other types of malware, or recruiting the computer as part of a botnet army that circulates spam. Rootkits can also enable ‘denial of service’ (DoS) attacks, whereby the targeted machine is flooded with requests until it can’t carry out its normal functions. Even bigger, bolder (and more destructive) are ‘distributed denial of service’ (DDoS) attacks where multiple systems target single prey. They’re like DoS on steroids.
And you may want to speak softly… Cybercriminals can also use rootkits to hack your device’s webcam and microphone to eavesdrop on your conversations. They might invade your privacy in other ways too, such as by reading your emails, intercepting network traffic and tracking your keystrokes. Some rootkits can tamper with or even disable computer security systems altogether, making it harder to detect unusual behaviour and unauthorised changes.
Is a rootkit a virus?
Let’s think more broadly for a minute. Malicious software or ‘malware’ is a catch-all term for software that’s designed to disrupt, damage, or gain unauthorised access to a computer system. It can take many forms, from computer viruses and spyware through to adware and ransomware. Rootkits are definitely malware, but are they viruses?
Viruses are a specific type of malware that self-replicates by inserting its code into other programs. Rootkits are self-replicating, so they have some elements of a virus, but they need help getting into a system and can’t spread themselves alone. Although most rootkits affect the software and operating system (OS), they can have grandiose plans and infect your computer’s hardware and firmware (the software embedded into the hardware to help control its functionality). Rootkits may be found on any type of computer device, from smartphones to servers, so don’t think that your favourite machine is immune. And because they’re so well-hidden, they can be incredibly difficult to detect and remove. More on this later…
Meet the members of the rootkit family
Not all rootkits are created equal, and they’re categorised according to how they infect, work, and how long they last. Here’s a quick round-up of the usual suspects.
Bootkit or bootloader rootkits replace your authorised bootloader (that’s the mechanism that loads your operating system as soon as your computer is switched on) with a malicious one. This means that the rootkit is activated even before your computer’s OS is fully loaded!
Hardware or firmware rootkits are installed on the hard drive, router, or system BIOS (the software installed on a memory chip in the motherboard). Instead of manipulating your OS the way most malware does, these rootkits affect the device’s firmware and install malware that can hide from antivirus software. Hardware/firmware rootkits can be a major threat to online privacy and security as they can allow hackers to log your keystrokes and monitor your online activity.
Application rootkits replace legitimate files on the computer with rootkit files to change how applications work. These rootkits can be injected into programs you use every day, like Microsoft Office, Paint, or Excel—and every time you start up the infected program, the attacker gains access to your computer. This malware is tricky to detect as the infected programs appear to function normally! Reliable antivirus software like Avira Free Antivirus (available as a stand-alone product or as part of Avira Internet Security) can usually identify these culprits though.
Memory rootkits burrow into the depths of your computer’s random-access memory (RAM), where they run in the background, executing malicious attacks and usually slowing down the computer’s performance. These rootkits don’t inject permanent code, so they usually disappear as soon as you reboot the system.
Kernel mode rootkits strike at the very heart (i.e.: kernel level) of the computer system, making them the most serious of all rootkits. Hackers use them to attack the functionality of the OS by adding their own code. Beware—they can also access the files on your computer!
Virtual rootkits load themselves underneath the computer’s original OS and then place that OS onto a virtual machine. It’s precisely because they run separately from the computer’s OS that makes them so difficult to detect. Virtual machines are also used in legitimate IT practice to run multiple operating systems on one machine or to test programs in an isolated environment.
How are rootkits installed on a device?
Understanding how rootkits gain access to your computer can help prevent infection because, like Trojan malware, they need help to be installed. Rootkits provide hidden access and control, while Trojans act as a payload delivery mechanism. Don’t be the rootkit nice guy by unwittingly lending a hand!
Rootkits are a blended threat as they typically contain three components: In addition to the malware, hackers incorporate a terrible twosome called a dropper and a loader. First up is the dropper, which imports the rootkit onto the victim’s computer. The dropper then activates the loader which installs the rootkit onto the computer system. The cybercriminal must successfully land all three parts for their insidious plan to work and there are several methods they use.
Hitching a lift with trusted software: A rootkit can piggyback on legitimate programs and apps and will then be downloaded from the download portal along with the software that the user intended to have. (Reminder! Download programs only from trusted sources).
Via social engineering techniques: Scammers will reach out to victims with legitimate-sounding emails, trying to entice them to click on a link or download a file. Through this phishing and other types of social engineering, victims can download a rootkit and other malware. Viruses and Trojans are popular rootkit carriers, and both are excellent at sneaking onto computers.
Exploiting vulnerabilities: If a computer’s operating system or any software has unpatched weaknesses and the latest update hasn’t been installed, a hacker can slip their wares through the vulnerability. (Reminder: Keep all programs safely up to date).
Hijacking messaging programs: Watch out—a blended threat can hijack instant messaging clients and spread itself to the victim’s contacts. These messages contain infected links, and the rootkit is unleashed if the recipient clicks on the link.
Hiding in rich-content files: Hackers can embed rootkits into rich-content files like PDFs. As soon as you open the file, the rootkit dropper executes automatically.
Via drive-by downloads: You’re happily browsing the internet when you land on a malicious website or legitimate site that’s had malicious code injected. Even if you don’t interact with the site at all, simply being there can prompt malware installation on your device.
Are you infected with a rootkit? Look out for these common symptoms
As rootkits are designed to stay hidden, detecting them can be tricky and the longer these unwelcome guests stay, the greater the damage they can cause. Some are even able to disarm security software, providing added ‘cover’ for their actions and adding to your woes. Here are the common signs that your device may be infected with rootkit malware:
- Blue/black screen of death
Are you staring at Windows error messages or blue or black screens with white text? Does your computer constantly need to reboot?
- Slow system performance
Is your device suddenly freezing or crashing more than usual? Is it running more slowly and central processing unit (CPU) usage is higher? You might also notice unusual network traffic behind your usual operations.
- Changes in system settings and permissions
Has your antivirus software been disabled or stopped running, and you know you didn’t touch it? Perhaps you’ve noticed other changes to your system settings, like a different screensaver, the taskbar hiding, pinned items moving, or a different date/time displayed.
- Web pages function slowly and unpredictably
Has online browsing become frustratingly slow? Excessive behind-the-scenes network traffic could be the culprit. Also look out for sudden browser redirects and bookmarks you don’t recognise.
If you answered “yes” to many of these questions, your computer may indeed be in the grip of a rootkit or other malware. Leap to the next section to act fast and start repairing any damage to your computer system.
It’s time for action: How to help detect, remove, and prevent a rootkit
Follow our 5-step action plan to help embrace a rootkit-free fresh start—hopefully without proceeding to step 6!
STEP 1: Restart your computer and enter Safe Mode. This can prevent the rootkit from loading when your device boots, making it easier to remove. How to access safe mode depends on your operating system. For Windows 11, click Windows Start menu > Power > Restart (while holding down the Shift key).
STEP 2: Conduct a deep system scan with reputable, specialised online security software. Please make sure that all your online security tools are current to maximise your chances of catching the latest threats! It’s also worth remembering that rootkits can evade the basic protection that may come with your machine, so multi-layered security from online security specialists is recommended. If you’re using Avira Antivirus Pro, included with Avira Internet Security, you can run a quick smart scan or a full virus scan. The deep scan is recommended to help oust tough rootkits—it also scans the Windows system, active processes, plus local and removable drives.
STEP 3: Correctly remove identified threats. Always follow the instructions provided to remove or quarantine any rootkit-related process or files—and double-check that you’re removing the right ones! Deleting random system files can result in your computer not working properly. Avira Antivirus Pro moves suspected malicious files to an isolated safe space on your computer. Follow these instructions on how to restore or delete quarantined files with Avira.
STEP 4: Any damage? Now repair system files. It’s not all about nuking the bad guy. We need to protect the good. Rootkits can modify system configurations and files so these need to be repaired or amended.
STEP 5: Monitor system behaviour and carry out maintenance. Watch out for any signs of reinfection, such as performance and web browsing problems and run regular scans with your trusted, up-to-date online security software.
STEP 6. The last resort! Wipe the device and reinstall the OS. If all the above have failed and your rootkit is firmly embedded at multiple levels, try backing up your data, wiping your computer, and performing a new, clean install. First, see this guide to formatting your hard drive.
A match made in safe cyber-heaven: Safe online habits + trusted technology
Prevention really is better (and easier) than a cure when it comes to staying safer from online scams, rootkits, and other malware. Here’s a quick reminder before you head back into the digital jungles:
- Use trusted antivirus from online security specialists.
- Keep all systems up to date, including the operating system and all applications, so they’re more likely to be safely patched and free of loopholes known to cybercriminals. Don’t forget to update your internet browser too as the latest versions have built-in protection against fake websites.
- Recognise phishing emails. Double-check the sender by hovering over their address and never send confidential information by email or click on random links. If in doubt, directly contact the institution/company writing to you to verify that the communication is genuine.
- Only open attachments from trusted sources. Attackers spread rootkits and other malware by hiding viruses and Trojans in attachments.
- Engage only with reputable websites you know and trust and never shop on a site without the HTTPS padlock symbol. If a deal sounds too good to be true, you’re probably being conned—the website may even be laced with malware.
- Use strong, unique passwords and store and manage them more securely with a password manager. Where possible, set up multi-factor authentication.
Rootkit Hall of Fame: Meet four infamous examples
Rootkits can represent a serious and multifaceted threat. Here are a few infamous examples that showcase the power and reach of these digital threats:
As early as 2006, Rustock Rootkit created one of the largest botnets for sending spam. Estimates vary but suggest the botnet recruited between 150,000 and 2.4 million infected machines and sent an average of 192 spam messages per compromised machine per minute.
In 2010, Stuxnet Rootkit caused substantial damage to Iran’s nuclear program and is considered an act of cyberwarfare.
In 2011, Alureon/TDL-4 Rootkit stole data and compromised security systems. It infected 1.5 million computers in the US.
In 2012, Flame appeared and turned out to be a highly effective information-gathering tool for cyber espionage, particularly in the Middle East. It can affect a machine’s entire operating system, allowing hackers to monitor traffic, log keystrokes, and capture screenshots.
Online security has many layers: Effective protection goes beyond antivirus
Don’t become a victim of rootkits and other malware. Avira Internet Security combines multiple Avira premium products into a single, potent solution for enhanced identity and PC protection. Meet your personal security team: Avira Antivirus helps block even the latest online threats while the Software Updater identifies and installs the latest updates. Use the Password Manager to help generate and securely store complex passwords for all your online accounts—it also notifies you if your details have been exposed in a security breach. And you’ll be less worried about infected websites thanks to Avira Browser Safety, which helps stop infected websites from loading.