The WCry ransomware worm has struck again, this time prompting Honda Company to halt production in one of its Japan-based factories after finding infections in a broad swath of its computer networks, according to media reports.

The automaker shut down its Sayama plant northwest of Tokyo on Monday after finding that WCry had affected networks across Japan, North America, Europe, China, and other regions, Reuters reported Wednesday . Discovery of the infection came on Sunday, more than five weeks after the onset of the NSA-derived ransomware worm , which struck an estimated 727,000 computers in 90 countries . The mass outbreak was quickly contained through a major stroke of good luck. A security researcher largely acting out of curiosity registered a mysterious domain name contained in the WCry code that acted as a global kill switch that immediately halted the self-replicating attack.

Honda officials didn't explain why engineers found WCry in their networks 37 days after the kill switch was activated. One possibility is that engineers had mistakenly blocked access to the kill-switch domain. That would have caused the WCry exploit to proceed as normal, as it did in the 12 or so hours before the domain was registered. Another possibility is that the WCry traces in Honda's networks were old and dormant, and the shutdown of the Sayama plant was only a precautionary measure. In any event, the discovery strongly suggests that as of Monday, computers inside the Honda network had yet to install a highly critical patch that Microsoft released in March.

WCry repackaged a weaponized exploit developed, used, and eventually stolen from the National Security Agency. A still-unknown group calling itself the Shadow Brokers released the exploit, code-named EternalBlue, in April, in what was the most damaging release the group has made since it went public last August. Almost immediately, WCry shut down computers around the world, forcing hospitals to turn away patients and temporarily shutting down banks and Fortune 500 companies. Automakers Renault and Nissan Motor were among those affected; they suspended jointly operated plants in Japan, Britain, France, Romania, and India.

In May, it was hard to excuse so many companies not yet applying a two-month-old patch to critical systems that were vulnerable to advanced NSA exploit code put into the public domain. The failure is even harder to forgive five weeks later, now that WCry's wake of destruction has come into full view.