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- 23. What is a trojan/worm/virus/logic bomb?
-
- This FAQ answer was written by Theora:
-
- Trojan:
- Remember the Trojan Horse? Bad guys hid inside it until they could get
- into the city to do their evil deed. A trojan computer program is
- similar. It is a program which does an unauthorized function, hidden
- inside an authorized program. It does something other than what it
- claims to do, usually something malicious (although not necessarily!),
- and it is intended by the author to do whatever it does. If it's not
- intentional, its called a 'bug' or, in some cases, a feature :) Some
- virus scanning programs detect some trojans. Some virus scanning
- programs don't detect any trojans. No virus scanners detect all
- trojans.
- Virus:
- A virus is an independent program which reproduces itself. It may
- attach to other programs, it may create copies of itself (as in
- companion viruses). It may damage or corrupt data, change data, or
- degrade the performance of your system by utilizing resources such as
- memory or disk space. Some virus scanners detect some viruses. No
- virus scanners detect all viruses. No virus scanner can protect
- against "any and all viruses, known and unknown, now and forevermore".
- Worm:
- Made famous by Robert Morris, Jr. , worms are programs which reproduce
- by copying themselves over and over, system to system, using up
- resources and sometimes slowing down the systems. They are self
- contained and use the networks to spread, in much the same way viruses
- use files to spread. Some people say the solution to viruses and worms
- is to just not have any files or networks. They are probably correct.
- We would include computers.
- Logic Bomb:
- Code which will trigger a particular form of 'attack' when a
- designated condition is met. For instance, a logic bomb could delete
- all files on Dec. 5th. Unlike a virus, a logic bomb does not make
- copies of itself.
-