Popular Science Magazine had an article on “Who is running the phony cell phone towers” along with a map of some 20 plus that had been located. These “towers” look like a local service tower to all cell phones in range and can capture some “meta data” (phone #, ID, location info) without any need to decrypt actual calls, but could also do that with some additional effort.
Variations of this technology, “Stingray” and “Triggerfish” are available for sale, perhaps with some limitations on buyers — at least for major manufactures like Harris. How these are being used in the U.S. is being carefully protected according to a 2011 Wall Street Journal article. Popular Science indicates that a unit could be constructed for as little as $2000 by a knowledgeable hacker (at a maker-space near you no doubt), but did not point to any kits, plans or software available on the net at this time.
While the question posed by Popular Science and some other publications related to this recent survey of phony towers is “who is doing it?” — a more relevant observation is that any entity with resources and interest can do so in any country. It is probably illegal in most if not all countries, at least for non-governmental agencies, but with a low cost, low profile and difficult to detect characteristics you can bet it is being done. There are phones that can detect, and reject these tower connections, which is what the really bad guys might use (or disposable phones that they trash after every use which might be cheaper.)
While the “NSA” data collection revelations have sparked a lot of interest, and apparent “surprise” from foreign country officials — this potentially more “democratic” capability (everyone can do it) has not gotten the same press. Of course the opportunity for abuse is much greater with a comprehensive program managed by government entities, but the opportunity is there for unscrupulous actors to monitor our cellular presence (note just having your phone “on” provides for this tracking, no calls required.)
Technology has addressed the “how, what, when and where” issues, the “who and why” answers will vary from country to country and perhaps a new form of paparazzi as well.