Five major intelligence agencies including the NSA and GCHQ have been collaborating to create a map of the entire internet, and as part of that program the agencies have been breaking into service providers' networks to monitor them, according to dual reports in The Intercept and Der Spiegel. The mapping program was previously detailed in The New York Times, so in their reports, the two publications hone in on providers that have apparently been penetrated as part of this program in Germany, including the large operator Deutsche Telekom (notably, though, Deutsche Telekom says that it has detected no evidence of surveillance).
"You could manipulate links, turn them off or on, change bandwidth."
But one company that The Intercept spoke with did acknowledge the surveillance — and it was deeply concerned to have heard of it. In a short documentary, filmmakers Katy Scoggin and Laura Poitras capture a meeting between an Intercept journalist and staff of Stellar, a satellite communications firm, as the firm is presented with evidence that it's been the subject of GCHQ surveillance. The surveillance comes as part of the internet mapping program, known as Treasure Map, but Stellar's engineers point out with great concern that the government's access could allow them to do quite a bit more — including shut off internet access to various customers its client serves in Africa.
Of course, the accessing of Deutsche Telekom's networks could be a far bigger deal — should the documents in fact be accurate — but it appears to be unclear exactly how much these intelligence agencies actually have access to. The provider says it serves 143 million mobile customers and 17 million broadband lines, and Der Spiegel speculates that GCHQ's documents are implying that the agency could potentially have gained the ability to monitor data sent over all of these. That seems to be a fairly loose inference for now, though, and isn't the focus of these documents. The documents are also undated, so it's unknown when the agencies say they had access. That said, the NSA was previously reported to have broken into both Google and Yahoo to collect massive amounts of information, so this would not be entirely without precedent.