Malware remains a significant security threat to enterprises, with infections projected to rise to 6.5 billion in 2025. Malware, short for malicious software, is designed to harm devices and networks by stealing data, disrupting services, or enabling financial gain and hacktivism. It encompasses various types including viruses, worms, ransomware, bots, Trojan horses, keyloggers, rootkits, spyware, fileless malware, cryptojacking, wiperware, and adware. Each type has distinct characteristics and attack methods, such as viruses requiring human action to spread, worms self-replicating without intervention, ransomware encrypting files for ransom, and fileless malware evading traditional detection by residing in memory.

Preventing malware involves a combination of technical defenses and user awareness. Key measures include installing and regularly updating antivirus and antimalware software, applying OS and software patches, using firewalls, enforcing strong access controls and multifactor authentication, and conducting ongoing security training for employees. Specific prevention tactics vary by malware type, such as backing up data to counter ransomware, avoiding suspicious links to prevent Trojans and spyware, and using network segmentation to mitigate fileless malware. Despite evolving threats, maintaining good cyber hygiene and awareness remains essential to reducing malware risks.