US Treasury Secretary Janet Yellen's computer was hacked by Chinese state-sponsored hackers, with fewer than 50 unclassified files accessed. The breach, part of a larger espionage campaign, also affected two deputy secretaries and targeted the Treasury's unclassified systems, focusing on its role in sanctions, intelligence, and international affairs. Over 400 devices and more than 3,000 files across unclassified personal devices were compromised in the attack.