Definition of Boot Sector Virus

All computers are vulnerable at some point to computer viruses that are designed with newer and more advanced ways to infect systems. Use state-of-the -art antivirus software as the best measure against viruses that infect your PC once your operating system has loaded. However, there is a breed of viruses that attempt to infect your machine BEFORE your antivirus software is loaded. These are called boot sector viruses and represent a very real technological threat. According to Panda Security, a leading antivirus company, 12 percent of all PCs in the United States are infected with viruses, of which three percent are boot sector.

Background

Boot sector viruses exist with one purpose in mind - to infect your computer before any protection methods are loaded. It is important to understand what the boot sector is and why it is so vulnerable to attack from these types of malicious code. Every computer disk, from hard drives to thumb drives, is broken up into sections or quadrants. These sections are simply storage areas for data as it spreads across the disk.

The boot sector is the most important quadrant because it retains the information about where everything else is located. Every file stored on a hard disk is cataloged and indexed by the boot sector, so when your computer calls on a file, it knows where to look. When your PC is first turned on, the first place it looks for instructions is the boot sector and depends on it every time you use a computer.

Significance

Boot sector viruses are malicious code that attempt to infect your hard drive's master boot record and gain access to the locations of every file currently stored there. As soon as you power on your PC, the first command it looks for is what the hard drive has stored as the boot section for your operating system. If a boot sector virus is present, as the computer looks to the hard drive for its first set of instructions, the boot sector virus will be read first. Once this happens, everything that is loaded is run through whatever controls the virus has programmed. Therein lies the danger of boot sector viruses. They are able to gain control of your PC before any user intervention is possible and infection can spread rapidly. Even more, many of these types of viruses can run in full stealth mode, making them invisible to even the most ardent user.

Identification

Boot sector viruses spread through the use and sharing of infected thumb drives and floppy disks. It passes transparently into a vulnerable PC without the user's knowledge. The best time to identify a boot sector virus infection is when your operating system first tries to boot. Most often, an error stating "Disk access cannot be be used" will be displayed and your PC may fail to load the operating system. However, if the computer is able to fully load the system, most antivirus programs will detect a boot sector virus. Once this occurs, it is a fairly simple process of removing it; refer to your antivirus program for removal instructions.

Prevention/Solution

There many ways to prevent boot sector infections including using caution when sharing and swapping any removable media. Be it a thumb drive from a trusted source or a floppy disk in a public location, it is imperative that you exercise good practices before loading them into your computer. If possible, have it virus scanned before inserted into your PC and if that is not an option, inquire if the files are available on a CD-ROM instead of easily writable media. CD-ROMs will not pass boot sector viruses. Next, and this is a good overall practice, have the antivirus program fully up to date with its latest definitions. With the speed at which viruses are discovered, it speaks volumes to Internet safety by remaining up to date and protected.

Theories/Speculation

Since the Internet is now the primary source of information for most computer users, thumb drives and floppy disks have become obsolete. Because of this, boot sector virus will invariably follow this trend. Therefore, always keep a watchful eye on your PC when it comes to sharing disks of all types. Boot sector viruses can easily wreak havoc on an unsuspecting user and his valuable files.

References

• Trend Micro: Boot Sector Virus
• Symantec: History of Viruses
• Panda Security: Infection Map

Resources

• Microsoft.com: Detailed Explanation of FAT Boot Sector