Hackers who tapped into government networks through SolarWinds software potentially accessed about 3% of the Justice Department's email accounts, but there's no indication they accessed classified systems, a DOJ spokesperson said in a statement Wednesday.
The DOJ Office of the Chief Information Officer learned of the hack on Christmas Eve, according to the statement, where agents accessed the department's Microsoft Office 365 email environment.
"As part of the ongoing technical analysis, the department has determined that the activity constitutes a major incident under the Federal Information Security Modernization Act, and is taking the steps consistent with that determination," the spokesperson said. "The department will continue to notify the appropriate federal agencies, Congress, and the public as warranted."
On Tuesday, U.S. intelligence agencies said Russians were likely behind the breach, which impacted multiple government departments. Microsoft was also a victim of the hack, Reuters reported in December.