A prominent cybersecurity firm says suspected state-backed Chinese hackers exploited widely used networking devices to spy for months on dozens of high-value government, defense industry and financial sector targets in the U.S. and Europe. FireEye said Tuesday that it believes two hacking groups linked to China broke into several targets through Pulse Connect Secure devices, which numerous companies and governments use for secure remote access to their networks. The new disclosure comes at a time of heightened interest in U.S. cybersecurity defenses. U.S. officials are still grappling with the aftereffects of the SolarWinds intrusion, which affected the Treasury, Justice and Homeland Security departments.