Boot Sector Virus

Definition of Boot Sector Virus

A boot sector virus is a type of malware that infects the boot sector of a computer’s storage device, typically a hard drive or USB drive. This infection occurs when the virus attaches itself to the first physical sector, thereby interfering with the boot process and allowing the virus to load before the operating system. As a result, the malware can gain control of the system and potentially evade antivirus detection.


Boot Sector Virus in phonetics would be: / buːt ˈsɛktər ˈvaɪrəs /Breaking it down for each word:Boot: /buːt/Sector: /ˈsɛktər/Virus: /ˈvaɪrəs/

Key Takeaways

  1. Boot sector viruses are malicious software that infects the boot sector of a computer’s storage devices like the hard drive or USB devices. This makes the virus one of the first codes executed when a system starts up.
  2. These types of viruses can infect both Windows and macOS systems and can cause various issues, including data loss, corrupted files, and even rendering the computer unbootable without proper action.
  3. To protect a computer from boot sector viruses, it is essential to use a reliable antivirus software, keep the operating system updated, and avoid using untrusted storage devices or downloading potentially harmful files from unknown sources.

Importance of Boot Sector Virus

The term “Boot Sector Virus” is important because it refers to a type of malicious software that specifically targets the boot sector of a computer’s hard drive.

A boot sector is a crucial part of the system as it contains essential information related to the computer’s start-up and operating system.

A boot sector virus can corrupt, delete, or alter this data, rendering the system inoperable or behaving abnormally.

These viruses often spread through infected external storage devices or bootable media, thereby infecting multiple devices.

Understanding the concept and implications of boot sector viruses can help users take necessary precautions to protect their systems from such threats and ensure system security.


A boot sector virus is a type of malicious software (malware) specifically designed to infect a computer’s boot sector, the area of a hard drive or other storage medium that contains the critical information required to load the operating system. Through infecting this crucial area, the virus ensures that it gets executed during the system startup process, accomplishing its nefarious purpose.

The primary goal of a boot sector virus is to gain control over a computer system, paving the way for its attacker to carry out a plethora of harmful activities. By embedding itself into the boot sector, the virus can evade detection by anti-virus software, rendering it even more potent and difficult to extricate.

Boot sector viruses are commonly used by attackers to gain unauthorized access to sensitive data, to render the victims’ computers inoperable, or to form botnets which can be used for DDoS attacks or to distribute other types of malware. Moreover, since a boot sector virus begins execution from the moment the system starts, it establishes a stronghold that grants the attacker more time to perform various malicious tasks, such as file corruption, data theft, and keylogging, among others.

It is crucial to ensure that a computer system is protected against these insidious types of viruses, by employing security best practices and regularly updating antivirus software.

Examples of Boot Sector Virus

A boot sector virus is a type of malware that targets the boot sector of a computer’s hard disk drive (HDD) or other storage media. It infects the system by modifying the boot code and making copies of itself, often spreading to other storage devices. Here are three real-world examples of boot sector viruses:

Stoned Virus (1987): Stoned is one of the earliest known boot sector viruses that emerged in the late 80s. It infected the computer’s master boot record (MBR) and remained in the system memory, allowing it to transfer onto any subsequently inserted floppy disk. The virus would display the message “Your computer is now stoned” on infected machines. Despite causing little harm or data loss, it gained wide notoriety and spawned several variants.

Michelangelo Virus (1991): The Michelangelo virus, named after the renowned artist Michelangelo Buonarroti due to its activation date coinciding with his birthday (March 6), was another MBR-infecting virus. When an infected disk was booted on that day, the virus would overwrite the first 100 sectors of the HDD, leading to data loss. The virus gained significant media attention and caused widespread fear, although the actual number of infected computers was relatively low.

Brain Virus (1986): Also known as the Pakistani flu, the Brain virus is considered to be the first-ever IBM PC-compatible boot sector virus. Created by two Pakistani brothers as a way to track pirated copies of their heart-monitoring software, the virus would replace the MBR with its own code and mark the original as bad, while copying itself to any additional floppy disks inserted into the infected machine. The virus was relatively harmless, but it initiated the age of boot sector viruses.

Boot Sector Virus FAQ

1. What is a Boot Sector Virus?

A boot sector virus is a type of malware that infects the boot sector or partition table of a computer’s hard drive. This makes it one of the earliest forms of virus infection since it typically takes effect as soon as the system is booted up.

2. How does a Boot Sector Virus spread?

A boot sector virus typically spreads through infected storage devices, such as a USB flash drive or an external hard drive. When an infected device is connected to a computer and the system is booted up, the virus can transfer to the computer and infect its boot sector.

3. What are the symptoms of a Boot Sector Virus?

Some common symptoms of a boot sector virus include slow system performance, frequent crashes, data loss, and unusual error messages during boot-up. In some cases, the virus can also prevent the computer from booting up altogether.

4. How can I protect my computer from a Boot Sector Virus?

To protect your computer from a boot sector virus, always keep your operating system and antivirus software up-to-date. Additionally, be cautious when connecting external storage devices, and never use storage devices from unknown sources. Regularly scan your computer and storage devices for any signs of malware, and always maintain a backup of your files in case of data loss.

5. How can I remove a Boot Sector Virus?

If you suspect your computer is infected with a boot sector virus, run a full system scan with a reliable antivirus software. In some cases, specialized boot sector virus removal tools may also be required to completely eliminate the infection. Keep in mind that removing a boot sector virus can be a complex process, and it’s important to follow the instructions provided by your antivirus software to avoid making the situation worse.

Related Technology Terms

  • Master Boot Record (MBR)
  • Self-replication
  • BIOS (Basic Input/Output System)
  • File System
  • Data Recovery

Sources for More Information


About The Authors

The DevX Technology Glossary is reviewed by technology experts and writers from our community. Terms and definitions continue to go under updates to stay relevant and up-to-date. These experts help us maintain the almost 10,000+ technology terms on DevX. Our reviewers have a strong technical background in software development, engineering, and startup businesses. They are experts with real-world experience working in the tech industry and academia.

See our full expert review panel.


About Our Editorial Process

At DevX, we’re dedicated to tech entrepreneurship. Our team closely follows industry shifts, new products, AI breakthroughs, technology trends, and funding announcements. Articles undergo thorough editing to ensure accuracy and clarity, reflecting DevX’s style and supporting entrepreneurs in the tech sphere.

See our full editorial policy.

Technology Glossary

Table of Contents

More Terms