At least one clandestine network of American engineers and scientists who provide technical assistance to U.S. undercover operatives and agents overseas has been compromised as a result, according to two U.S. officials.
The Obama administration has scrambled to boost cyberdefenses for federal agencies and crucial infrastructure as foreign-based attacks have penetrated government websites and email systems, social media accounts and, most important, vast data troves containing Social Security numbers, financial information, medical records and other personal data on millions of Americans.
