This document defines key concepts related to information security. It discusses what information and information security are, as well as the multilayered nature of security. The main threats to information security are described as inadvertent acts, deliberate acts, natural disasters, technical failures, and management failure. Specific types of malware like viruses, worms, trojans, and spyware are explained. The document also differentiates between hackers and crackers and emphasizes the importance of using antivirus software to protect against threats.