The news of the suspected hack comes shortly after the report that White House officials had been using their personal emails for government communications.
It's unclear why Kelly spent so long with a messed up phone, and what data if any would have been obtained from the device.
A spokesman for the White House was not immediately available for comment.
Kelly was secretary of Homeland Security between late January and Late July, when he took the second most powerful job in the West Wing.
Google unexpectedly announce Google Clips, a camera with machine learning built in
Clips will light up so people know it's recording, and there's a button too for manually shooting. The key here is that it uses artificial intelligence to capture the right moment.
Politico reported Thursday that "three USA government officials" believed Kelly's phone was breached, possibly by hackers or foreign governments - and giving them access to critical data.
Officials don't know what data, if any, may have been accessed from Kelly's personal phone. In September, administration aides circulated a memo detailing the incident and recommending that Kelly stop using the phone.
"The [attackers] I would be most anxious about are nation-states or other actors who may have access to resale of commercial spyware sold to nation-states. Really the only way to pick up on that is to do forensics on the phone".
Staffers revealed that many phone functions were not working, and the IT department said the handset should not be used further.
Trump's own cell phone use came under scrutiny during the campaign and in the early days of his administration, as he reportedly used a Samsung device running an Android operating system that was unsecured.