China Accuses U.S. of Cyberattacks on Defense Firms via Microsoft Exchange Flaws

China's Cyberspace Administration has accused U.S. operatives of exploiting vulnerabilities in Microsoft Exchange to target defense-related enterprises. The attacks, detailed in a Bloomberg report, allegedly compromised a major defense supplier's email infrastructure for nearly a year. Microsoft, frequently at the center of such disputes, has historically attributed similar breaches to Chinese state-backed groups.

The allegations follow a 2021 incident where Chinese hackers breached thousands of Exchange servers, and a 2023 campaign that infiltrated high-ranking U.S. officials' email accounts. Microsoft recently disclosed that Chinese-linked groups exploited SharePoint vulnerabilities, prompting cybersecurity experts to note the tit-for-tat nature of global cyber warfare. "Every nation state carries out offensive cybersecurity campaigns," said Jon Clay of Trend Micro.