DEFINITION

• A type of malicious software designed to replicate itself and spread from one system to another, often without the user’s knowledge. Once executed, it can corrupt, steal, or delete data and disrupt system functionality. 

• There are financial variations of this attack. This still remains the most common form of attack on end-users.

DAMAGE

• Corrupts critical files, rendering systems unusable.

• Steals sensitive information, including login credentials.

• Slows down or crashes systems, affecting productivity.

• May enable attackers to gain unauthorized access to networks.

EXAMPLES/USAGE

• Mydoom (2004): One of the fastest-spreading viruses, it created backdoors on infected systems and launched distributed denial-of-service (DDoS) attacks.

• Stuxnet (2010): A highly sophisticated virus targeting industrial systems, it disrupted Iran’s nuclear program by attacking PLCs (Programmable Logic Controllers).

• Conficker (2008): Exploited Windows vulnerabilities to form a massive botnet, infecting millions of systems.

• WannaCry (2017): A ransomware virus that exploited a Windows vulnerability, encrypting files and demanding payment. It caused widespread disruption, including to healthcare services.

• Code Red (2001): Exploited web server vulnerabilities to deface websites and perform DDoS attacks, notably against the White House website.

• Zeus (2007): A banking Trojan that captured keystrokes and stole sensitive financial information from infected devices.

• Sasser (2004): A worm that caused infected computers to restart repeatedly by exploiting a vulnerability in Windows.