📹 Join the wait list

FULL SECURITY+ IN 31 DAYS COURSE 📹 Join the wait list - https://certbros.kit.com/01730e35f7 BOSON PRACTICE EXAMS ✔ Best practice exams - https://www.certbros.com/security-plus/exsim HAVE A QUESTION? 💬 Discord - https://www.certbros.com/discord Disclaimer: Some of these are affiliate links. If you purchase using these links, I'll receive a small commission at no extra charge to you. --------------------------------------------------------------------------------------------------------------- In this video, we explain computer viruses, including how they work, how they spread, and how they differ from other malware like worms and trojans. What is a computer virus? A computer virus is malicious code that attaches to a legitimate file or program and activates when that infected file is executed. Just like a biological virus needs a host to reproduce, a computer virus needs a host file to run and replicate. This is the key difference between a virus and other malware types. Viruses typically need user interaction, for example opening a file or running a program, before they can do anything. Once executed, a virus can replicate and spread across a system, and depending on its design it may: - Corrupt or delete files - Steal data - Modify system behaviour - Run silently in the background Common types of computer viruses Boot sector viruses These target the boot process by infecting the boot sector and, historically, the Master Boot Record (MBR). They load before the operating system when a machine boots from infected media. They were more common in older BIOS and MBR setups. Modern systems using UEFI and protections like Secure Boot have made this approach much less effective. Macro viruses Macro viruses use embedded scripts in documents such as Word and Excel, often written in VBA. They run when a user opens a document and enables macros. Many attacks rely on social engineering to convince users to enable content. Resident viruses Resident viruses load into memory and remain active even if the original infected file is removed. They can continue infecting other files and processes, which makes them harder to detect and remove. Polymorphic viruses Polymorphic viruses change their code or appearance as they spread while keeping the same behaviour. This helps them evade signature-based antivirus detection, forcing defenders to rely more on behaviour analysis and heuristics. Multipartite viruses Multipartite viruses infect multiple areas of a system, commonly combining boot sector infection with file infection. This makes cleanup difficult because removing one part may not remove the infection completely.