What Is Malware and How Does It Affect Your Computer?
Malware is any program that’s designed to harm computers and networks. Depending on the type of malware, these programs can steal or encrypt data; alter or hijack core computing functions; and spy on end users’ computer activity without their knowledge. They can also cripple business operations, cost companies millions in losses, and threaten personal privacy.
The first modern viruses began with the 1982 Elk Cloner virus, which spread by infecting floppy disks. Trojan horses masquerade as harmless programs to gain unauthorized access and install other malicious software. Logic bombs concealed in programs can be triggered by a user action or released at a predetermined time to crash systems or wipe a hard drive. Computer worms replicate themselves to spread through networks, unlike viruses that infect files on a single host computer.
Some types of malware, like banking trojans, steal financial information to drain victims’ bank accounts; spyware gathers personal or confidential data without the user’s knowledge to blackmail victims or sell to third parties; and ransomware locks up a system and demands payment for the keys to unlock it. Others, such as botnets, are large networks of infected computers controlled by an attacker and used to attack websites or launch DDoS attacks.
Other types of malware, such as adware and scareware, generate revenue for the attacker by spamming the victim with ads or by tricking them into installing a scam “security” program. A sudden appearance of invasive advertisements, odd charges on your phone bill or a puzzling increase in your data usage may indicate the presence of adware.