A computer worm is a type of malware that spreads copies of itself from computer to computer. A worm can make a copy of itself without any human interaction, and it does not need to attach itself to a software program in order to move around. However they often get onto a computer via attachments and un-updated software
- change and delete files
- install other malicious software on a computer
- steal data
- install a backdoor (hidden access)
- allow a hacker to gain control over a computer and its system settings
- use up system resources such as hard disk space, bandwidth on a network, CPU etc by making endless copies of itself (this makes you computer run slower and slower until it can't really function properly)
To stop worms you need antivirus software , keeping your software up to date also makes it a lot harder for worms to infect your computer.