What is a Resident Virus? Examples and Protection

Resident Virus is a type of malware that hides and saves itself in the computer’s memory. Depending on how the virus is programmed, it can infect any file run by the computer. This type of virus can even attach itself to anti-virus software, allowing it to infect any file verified by the program.

What is a Resident Virus?

A Resident Virus is a type of computer virus that embeds itself into the memory of your computer. Once it’s in the memory, it can execute its malicious code whenever the operating system runs, without needing to infect specific files first. This makes resident viruses particularly dangerous because they can activate and replicate themselves whenever you turn on your computer, even if you don’t open or run a specific infected program. If a resident virus enters, it infects other files and programs. This Malware is one of the most harmful because it can penetrate any file examined by antivirus tools and attach itself to antivirus software.

Resident Virus Examples

• CMJ Virus: One of the earlier examples of a resident virus, it infects .exe files and can stay memory-resident, executing its payload without the need to run the infected files again.
• Randex: This virus spreads through network shares and can receive commands from an attacker via a network. It resides in memory, making it active even if the infected file isn’t being executed.
• Mebroot: Mebroot infects the Master Boot Record (MBR), ensuring it is loaded into memory before the operating system. From there, it can carry out its malicious activities carefully.
• Virut: It is known for infecting executable files and HTML files, Virut creates a backdoor that allows remote access to the infected computer. Being a memory resident allows it to continuously spread and opens the door for further infections.
• Conficker: Conficker can reside in memory and infect devices across networks. It exploits vulnerabilities in Windows OS to spread and can disable security services, making it harder to remove.

Symptoms of Resident Virus

• The operating system becomes slow.
• Pop-up panels that appear from anywhere.
• Resident viruses decrease the system’s performance.
• The computer crashes and freezes without any reason.
• The resident virus affects executable files.
• Resident viruses consume large amounts of CPU and memory resources.

Protection from Resident Virus Attacks

• Install Reliable Antivirus Software: Choose a reliable antivirus program that offers real-time protection. This software continuously monitors your system for malicious activity, including resident viruses.
• Keep Your Antivirus Updated: Regularly update your antivirus software to ensure it can detect and neutralize the latest viruses and malware. Security software is only as good as its most recent update.
• Update Your Operating System and Software: Cybercriminals often exploit vulnerabilities in outdated software and operating systems. Regular updates can make it harder for viruses to infect your computer.
• Use a Firewall: Firewalls can prevent unauthorized access to your computer, blocking malicious software from being downloaded.
• Be Cautious with Email Attachments and Downloads: Don’t open email attachments or click on links from unknown sources. Be careful about downloading files from the internet, especially from untrusted or suspicious websites.
• Avoid Using Pirated Software: Pirated software can often be a source of malware, including resident viruses. Always use legitimate and updated software.
• Regularly Back Up Your Data: Regular backups can’t prevent an infection, but they can mitigate the damage by allowing you to restore your system to a clean state in case of an attack.

Difference Between Resident and Non-Resident Virus

Feature	Resident Virus	Non-Resident Virus
Location	Installs itself in the computer’s memory.	Does not remain in memory; resides in the infected file.
Operation	Can operate independently of the original infected file, affecting the system continuously.	Needs the infected file to be executed to spread or cause damage.
Detection and Removal	More difficult to detect and remove due to its presence in memory and continuous operation.	Easier to detect and remove, as it is not active until the infected file is executed.
Method of Spread	Can infect other files without any need for the infected file to be opened again after the initial infection.	Spreads by replicating itself when the infected file is executed, then infecting other files and programs.
Stealth and Impact	Often more stealthy and potentially more damaging because it can interfere with system operations directly.	Less stealthy and its impact is limited to the times when the infected file is executed.
Examples	Mebroot, Virat.	Classic file infectors like the Cascade virus

Conclusion

Resident viruses are malware that hide in your computer’s memory, causing trouble without you even knowing. But by following some steps like using updated antivirus software, keeping your system updated, and being careful with what you download and open, you can keep these unwanted user away. Remember, staying safe online is all about being alert and prepared. So, keep your software up to date, and back up your important activity which must be performed regularly.

Frequently Asked Questions on Resident Virus – FAQs

Who made the resident virus?

The resident virus was created in 1986 by Amjad Farooq Alvi and Basit Farooq Alvi in Lahore, Pakistan.

Is memory a resident virus?

Memory-resident viruses are among the oldest and most common types of computer viruses, they are designed to reside and can hide in a computer’s memory, and can be activated whenever the operating system is running, infecting all files that are opened.

Can resident viruses be removed?

Yes, resident virus can be removed with antivirus software that is specifically designed to detect and eliminate them.