Russian military-linked hackers targeted — and in some cases successfully infiltrated — the networks of European military, energy and transportation organizations in an apparent spying campaign that went undetected for months as the war in Ukraine raged, Microsoft told its customers in a report obtained by CNN. A tip from Ukrainian officials led Microsoft to investigate the cyber activity and discover that the Russian hackers had been exploiting the a previously unknown flaw in Microsoft’s email software between April and December 2022, according to Microsoft. US officials have braced for potential collateral damage to US organizations from alleged Russian hacking operations in Ukraine and elsewhere during the war, but such ripple effects have largely failed to materialize