What Is Malware and How Does It Affect Your Computer?
Malware is software designed to harm computers, smartphones and other devices. It can steal sensitive information, alter or disrupt core computer functions and communicate back to attackers without users’ knowledge. Its motives vary, from financial gain to sabotage.
Threat actors often use malware to spread to other systems, including infected removable media such as USB sticks and DVDs. They also rely on phishing attacks that use familiar email formats and messages to trick recipients into clicking malicious links or files. They may also co-opt standard Internet file system and network file system protocols to distribute malware files.
Viruses, worms, Trojan horses and spyware are common types of malware. They often have similar characteristics, but some have unique traits such as a syncing feature that allows them to spread via multiple communications channels. Viruses are the oldest type of malware and are usually hidden inside seemingly innocuous programs, such as PDF converters or apps that display product discounts or caller ID functionality on a smartphone. Once downloaded, they make unauthorized changes on the device by displaying pop-ups, redirecting search results or adding icons to desktops.
A common objective for malware is to exfiltrate data, which can be accomplished by encrypting or deleting files or secretly recording keystrokes. Another popular goal of malware is to disrupt services, ranging from shutting down devices to blocking access to websites or online banking services. Ransomware, the malware of choice for many cybercriminals, has achieved this in recent years by encrypting files and demanding payment to restore access.