Computer worms are similar to computer viruses in that they replicate functional copies of themselves and can cause the same damage.
Unlike viruses, which require the spread of an infected host file, worms are standalone software and do not require a host program or human assistance to spread.
To spread, worms either exploit a vulnerability in the target system or use some kind of social engineering to trick users or force users to execute them.
The worm enters a computer through a vulnerability in the system and uses the functions of transferring files or information in the system, allowing it to move around without assistance.
More advanced worms use encryption, virus, and ransomware technologies to harm their targets.
The biggest danger of a worm is its ability to reproduce on your computer, so it can send hundreds or thousands of copies of itself, rather than your computer, by sending a single worm, which has a hugely destructive effect.