Researcher who halted WannaCrypt wins $13k bug bounty

The British security researcher who found a way to slow down the spread of the WannaCrypt ransomware worm that struck over the weekend has received a cash reward for his work from bug bounty co-ordinator Hacker One.

Hacker One co-founder Michiel Prins announced the US$10,000 (A$13,500) bounty to the researcher dubbed MalwareTech for discovering a domain name hard coded into WannaCrypt as a "kill switch".

MalwareTech said he stumbled across the domain name while testing a sample of the malware.

WannaCrypt tests if it can reach the domain, and if not, continues to spread. As the domain name was unregistered the test would always fail, allowing the malware to continue its rampage.

MalwareTech registered the domain, causing the malware to halt its attempts at infection, thereby slowing down WannaCrypt intrusions considerably.

The researcher said he was hampered by law enforcement agencies erroneously issuing take-down requests in his effort to continue to run the sinkhole servers for WannaCrypt requests for the domain name.

"We lost two sinkhole servers due to a take-down request from law enforcement, but these were immediately replace to ensure no downtime," he said.

MalwareTech has been dubbed an internet hero for his actions.

The researcher said he would split the bug bounty between charities and buy information security books for students who cannot afford them.