The media is particularly happy to lie about Trump, but I have noticed that
A: They often have photographs of Trump through the White House window, with the slats and the panes clearly visible in the shot.
B: They often present information (like the phone call with the Australian) as if they are there in the room and can hear what people in the room say.
There is a possibility that the whole place is bugged, but I do hope Trump has at least some people loyal to him capable of scanning the place.
One would also assume a laser microphone pointed at the window might raise some alarms, yet we have to realize they are letting these photographers point their cameras at it. It may or may not require someone looking the other way, but it is not as unlikely as a whole roomful of bugs not being noticed.
Given their tendency to have both these pictures and a tale, well, it seems likely. Additionally, now the media is saying this is the 'leakiest' administration. Part of that is likely true, as there are both SJWs as well as establish conservatives that still need to be kicked out. But some want to suggest people close to Trump want to and regularly leak. I think some advanced eavesdropping is more likely.