operating-systems security malware

Definition

Malware

Malware (Malicious Software) is any software intentionally designed to cause damage to a computer, server, client, or computer network.

Types of Malware

Virus

Malicious code hidden within a legitimate program that replicates itself by infecting other programs. It requires a host to spread.

Worm

A standalone program that replicates itself and sends copies over a network (e.g., via email or remote login) to infect other computers. It does not require a host program.

Trojan Horse

A program that appears to have a useful or desired function but contains hidden malicious code. It is often downloaded voluntarily by the user.

Logic Bomb

A piece of code that remains dormant until triggered by a specific condition, such as a certain date or the absence of a specific user login.

Trapdoor (Backdoor)

A secret entry point into a system that allows someone to bypass normal security and access control mechanisms.

Attack Methods

  • Denial of Service (DoS): Overloading a system so it can no longer provide its intended service.
  • Distributed Denial of Service (DDoS): A coordinated DoS attack originating from many different sources simultaneously.
  • Keylogger: Software that records keystrokes to steal passwords or sensitive information.
  • Buffer Overflow: Writing data beyond the end of a buffer to overwrite the stack, potentially allowing the execution of malicious exploit code by overwriting the return address.
  • Port Scan: Automated searching for open network ports to exploit known vulnerabilities.
  • Social Engineering: Using deception (e.g., phishing) to manipulate individuals into divulging confidential information.