An international cyberattack struck parts of Europe, Asia, and the United States on Tuesday, crippling tens of thousands of computers at banks, hospitals, and government offices worldwide. Initial analysis found that the attack was designed for profit, with the hackers demanding $300 in Bitcoin in exchange for unlocking victims’ screens. But further evidence now suggests that the malware was a “wiper,” designed to destroy data on targets’ storage systems regardless of whether they gave in to the monetary demand.