DETROIT (AP) - A Purdue University graduate helped stop a global cyberattack over the weekend.

Darien Huss is a 28-year-old research engineer for the cybersecurity firm Proofpoint. Huss discovered a "kill switch" on Friday in the malware used in a cyberextortion scheme that was quickly spreading around the world.

U.S. officials are praising his work. Huss and another person stopped the attack by analyzing the hackers' messages demanding a ransom.

PREVIOUS | Global cyberattack: A super-simple explanation of what happened | Global cyber attack may not be finished yet | World reels from cyberattack that hit nearly 100 countries

"Once the kill switch was activated, the malware would simply do nothing. It would not carry out its infection. It would not take for ransom all the files on that computer," he said.

Huss says he's happy the outbreak was stopped fairly quickly, but he's worried about another attack in the coming days.