Without nuclear deal, U.S. expects resurgence in Iranian cyberattacks

Within 24 hours of Mr. Trump announcing on Tuesday that the United States would leave the deal, researchers at CrowdStrike, the security firm, warned customers that they had seen a “notable” shift in Iranian cyberactivity. Iranian hackers were sending emails containing malware to diplomats who work in the foreign affairs offices of United States allies and employees at telecommunications companies in an attempt to infiltrate their computer systems.

And security researchers discovered that Iranian hackers, most likely in an intelligence-gathering effort, have been quietly probing internet addresses that belong to United States military installations in Europe over the last two months. Those researchers would not publicly discuss the activity because they were still in the process of warning the targets.