As far back as December 2016, the White House believes chief of staff John Kelly's personal cell phone was breached, according to a report Thursday by Politico.
If true, it's possible hackers were able to access data on his phone both while he was Homeland Security secretary and White House chief of staff. It is, however, not clear whether or what data may have been accessed, according to the report.
The hacking was discovered over the summer, when Kelly complained that the phone wasn't working -- and hadn't for months -- and asked technical staff to take a look at it, according to the report.
Politico reports that staffers tried to figure out what had happened to the phone for "several days" before concluding it had been compromised.
The White House told Politico that Kelly had not been using the phone often, instead relying on his government phone. Raj Shah, a White House spokesman, told CBS News, "Last December, Gen. Kelly's personal phone stopped working, and he discontinued its use."
The White House did not confirm the report that his cell phone had been compromised, calling it a security matter.