Both the Police Security Service (PST), which carries out domestic intelligence, and the Norwegian Intelligence Service, which is responsible for military intelligence, on Wednesday said that there was no evidence that IMSI catchers, which mimic mobile phone base stations, are operating in central Oslo.
PST accused the Aftenposten newspaper, which claimed in December that it had found a series of stations, of reporting “inadequate information based on misinterpretations”.
“PST's investigation has not revealed any evidence of IMSI catchers [fake base stations] in the material Aftenposten presented,” PST's Siv Alsén wrote in a report published on Wednesday. “We are critical of the company that conducted the measurements and wrote the report that uncovered the IMSI catchers.”
The Norwegian Intelligence Service, backed up PST's report later in the day, pointing out that as well as having access to Aftenposten's figures, it also had access to confidential information from telecom operators, allowing it to a better judgement than Aftenposten.
Aftenposten is refusing to back down on its claims, made last December on the basis of a survey of the area using modified mobile phones designed to identify and avoid fake base stations.
It said that a new secret report by Delma, a British security firm, sent to PST in March but not referred to in the report PST released on Wednesday, had proven beyond all doubt that IMSi catchers were operating in central Oslo.
“What we see in the data is pure espionage,” Gordon McKay, Delma's chief executive, told Aftenposten after carrying out its study.
The British company would not speculate on who was behind the base station, but told Aftenposten that the way the station behaved reminded him of the Russian-made “White Russian” equipment.
“To me this looks like an IMSI-catcher,” Karsten Nohl, one of the world's leading experts on mobile surveillance, told the paper. “It gives a fake area code and the phone is denied service. Other characteristics also fit with our experience with IMSI catchers.”