Malicious Software (Viruses, Trojans, Ransomware)

Malicious software (malware) is any program or code designed to damage, disrupt, or gain unauthorized access to computers and networks. Understanding the main types of malware helps you recognize and prevent attacks.

1. Viruses

• Definition: Malicious programs that attach themselves to files or software and spread when those files are shared.
• How They Work: A virus can delete files, corrupt data, slow down your computer, or spread to other systems.
• Example: A virus hidden in a free software download infects every document it touches.

Prevention:

• Use antivirus software.
• Avoid downloading from untrusted sources.
• Keep operating systems and apps updated.

2. Trojans

• Definition: Malware disguised as legitimate software. The name comes from the Trojan Horse myth.
• How They Work: Victims install what they believe is safe software, but the Trojan secretly creates backdoors, steals data, or downloads more malware.
• Example: A “free game” download that silently installs spyware.

Prevention:

• Download software only from official websites.
• Be cautious with email attachments and links.
• Use firewalls to block suspicious traffic.

3. Ransomware

• Definition: Malware that encrypts files and demands payment (a ransom) to unlock them.
• How They Work: Often spread through phishing emails or infected attachments. Once activated, it locks the user out of their own data until ransom is paid (usually in cryptocurrency).
• Example: The infamous WannaCry attack (2017) that impacted hospitals, businesses, and governments worldwide.

Prevention:

• Keep backups of important files (offline or cloud-based).
• Update systems regularly to fix vulnerabilities.
• Don’t click unknown links or open suspicious files.

Key Takeaway:

Viruses, Trojans, and Ransomware are different forms of malware, but they share one goal: to exploit systems for harm or profit.
Strong security practices and awareness are your best defense.