Sasser is a computer worm that was first discovered in 2004. It spreads by exploiting vulnerabilities in the Microsoft Windows operating system, specifically targeting systems that have not been updated with the latest security patches. Once it infects a computer, Sasser can cause it to crash or reboot unexpectedly, disrupting normal operations. The worm was created by a German teenager named Sven Jaschan, who was later arrested for his actions. Sasser's rapid spread led to significant disruptions worldwide, affecting thousands of computers and prompting organizations to enhance their cybersecurity measures to prevent similar attacks in the future.