Russian hackers used compromised systems at the Executive Office of the President to access the President’s schedule.
How could Russian hackers get to the President’s schedule? CNN reports:
As in many hacks, investigators believe the White House intrusion began with a phishing email that was launched using a State Department email account that the hackers had taken over, according to the U.S. officials.
All the advanced cyber-defenses used to protect the White House were defeated by tricking users with deceptive emails. Spearphishing is not a casual hit and miss activity, it is the precise application of Military Deception. This is the problem that SP Guard addresses by providing tools to identify deceptive emails.