Back Door

A feature programmers often build into programs to allow special privileges normally denied to users of the program. Often programmers build back doors so they can fix bugs. If hackers or others learn about a back door, the feature may pose a security risk. Also: Trapdoor.

Back Orifice

Back Orifice is a program developed and released by The Cult of the Dead Cow (cDc). It is not a virus; it is a remote administration tool with potential for malicious misuse. If installed by a hacker, it has the ability to give a remote attacker full system administrator privileges to your system. It can also 'sniff' passwords and confidential data and quietly e-mail them to a remote site. Back Orifice is an extensible program--programmers can change and "enhance" it over time. See Also: Password Sniffing

Background Scanning

A feature in some anti-virus software to automatically scan files and documents as they are created, opened, closed or executed.

Background Task

A task executed by the system but generally remain invisible to the user. The system usually assigns background tasks a lower priority than foreground tasks. Some malicious software is executed by a system as a background task so the user does not realize unwanted actions are occurring.

Backup

n. A duplicate copy of data made for archiving purposes or for protecting against damage or loss.

v. The process of creating duplicate data. Some programs backup data files while maintaining both the current version and the preceding version on disk. However, a backup is not considered secure unless it is stored away from the original.

Batch files

Text files containing one MS-DOS command on each line of the file. When run, each line executes in sequential order. The batch file AUTOEXEC.BAT is executed when the computer is booted and loads a series of controls and programs. This file type has the extension BAT.

Bimodal virus

A bimodal virus infects both boot records and files. Also: Bipartite; See Also: Boot Sector Infector, File Virus, Multipartite

BIOS

Basic Input/Output System. The part of the operating system that identifies the set of programs used to boot the computer before locating the system disk. The BIOS is located in the ROM (Read Only Memory) area of system and is usually stored permanently.

Boot

To start (a cold boot) or reset (warm boot) the computer so it is ready to run programs for the user. Booting the computer executes various programs to check and prepare the computer for use. See Also: Cold Boot, Warm Boot

Boot Record

The program recorded in the boot sector. This record contains information on the characteristics and contents of the disk and information needed to boot the computer. If a user boots a PC with a floppy disk, the system reads the boot record from that disk. See Also: Boot Sector

Boot Sector

An area located on the first track of floppy disks and logical disks that contain the boot record. Boot sector usually refers to this specific sector of a floppy disk, whereas the term Master Boot Sector usually refers to the same section of a hard disk. See Also: Master Boot Record

Boot Sector Infector

A boot sector infector virus places its starting code in the boot sector. When the computer tries to read and execute the program in the boot sector, the virus goes into memory where it can gain control over basic computer operations. From memory, a boot sector infector can spread to other drives (floppy, network, etc.) on the system. Once the virus is running, it usually executes the normal boot program, which it stores elsewhere on the disk. Also: Boot Virus, Boot Sector Virus, BSI.

Brute Force Attack

An attack in which each possible key or password is attempted until the correct one is found. See Also: Attack

BSI

See: Boot Sector Infector

Bug

An unintentional fault in a program that causes actions neither the user nor the program author intended.