The security of one of the U.S. government's most sensitive computer networks may have been breached by Chinese hackers, according to The Washington Free Beacon. White House Military Office computers, a network responsible for issuing nuclear commands, arranging presidential travel and heading intergovernmental teleconferences between high-ranking officials may have fallen to a phishing attack, The Washington Free Beacon reported. But an unnamed official reportedly said, “In this instance the attack was identified, the system was isolated, and there is no indication whatsoever that any exfiltration of data took place.”

Falling into the “social engineering” category, phishing is not hacking, but typically involves tricking a target into handing over sensitive information. By sending emails or instant messages that link to a fraudulent website very similar in appearance to a real website the target is familiar with, a phisher can sometimes obtain sensitive information, like user names and passwords.

Security officials are investigating the possible impact of the attack and an unnamed official told The Washington Free Beacon that no sensitive data was compromised. “This is the most sensitive office in the U.S. government,” a former senior U.S. intelligence official familiar with the work of the office said. “A compromise there would cause grave strategic damage to the United States.”

Issues of federal cybersecurity have made headlines recently as Congress failed its attempts to agree on suitable legislation. While nearly everyone involved agrees on the importance of passing cybersecurity legislation, politics stood in the way, cuing a possible presidential executive order.