Jeffrey Lee Parson
Minnesota teenager convicted over a variant of the Blaster worm, while the author of the original was never found.
Blaster spread in August 2003 through a hole in Windows DCOM RPC that Microsoft had already patched. It infected hundreds of thousands of machines and was programmed to flood windowsupdate.com with a DDoS attack, leaving behind the message "billy gates why do you make this possible?".
Parson did not write the original. He took the existing worm, made a variant that dropped a backdoor, and had it phone home to a website registered in his own name under the handle "teekids". He was arrested within two weeks and sentenced in 2005 to eighteen months in prison. The author of the original worm was never identified, which makes Parson a useful reminder that it isn't the most skilled who get caught.