A worm is a malicious program that replicates itself by using system vulnerabilities such as unprotected file sharing networks. Just like for other viruses, propagation is the main aim for worms but the difference is that worms are self-contained and does not need to be a part of another program. Most of them hide in active memory with a reason to perform malicious actions, infecting and corrupting files, degrading overall system performance and security, stealing sensitive information or installing other dangerous parasites.