Trojan Horses, Computer Viruses, and Worms

Related Concepts

Dynamic Malware Analysis; Malware Behavior Clustering; Malware Detection; Reverse Engineering of Malware Emulators; Unpacking Malware

Definition

A program which is different from the specified (specs) one is said to contain a Trojan horse. The Trojan horse may be malicious. It is undecidable to decide whether a program is free of Trojan horses.

Theory

A Trojan horse that, when executed, can modify other computer programs, e.g., by copying itself (or a part of it) into these is called a computer virus. Protection mechanisms used against computer viruses are to:

• Use digitally signed computer programs. Provided these digitally signed programs were developed in a secure and trusted environment, then one can detect modifications to the digitally signed program [3]. (For implementation issues see [1].) If the environment was not trusted, known computer viruses may be in the digitally signed program and remain undetected unless virus scanners are used also.

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