‘On Sunday, the Washington Post published an exposé revealing that private companies are peddling surveillance systems to foreign governments that track the location of cellphone users in the United States and abroad. The report raised a basic question: How can this be happening when cellphone companies generally promise not to disclose their customers’ location information without their consent? The main problem is that location information is available on a global network that can be accessed by thousands of companies. And in the wake of the Post story, US cellphone companies are refusing to discuss how this squares with their privacy policies, or say what they are doing to keep their customers’ whereabouts confidential.
Here’s what’s going on: Carriers collect location information from cellphone towers and share it with each other through a global network called SS7. This allows a US carrier to find a customer even if she hops a plane to India. But according to the Post, surveillance systems makers have gained access to SS7 and are using it to grab location data, allowing these firms to pinpoint people within a few city blocks.’