Krebs on Security: “A new breach involving data from nine million AT&T customers is a fresh reminder that your mobile provider likely collects and shares a great deal of information about where you go and what you do with your mobile device — unless and until you affirmatively opt out of this data collection. Here’s a primer on why you might want to do that, and how. Telecommunications giant AT&T disclosed this month that a breach at a marketing vendor exposed certain account information for nine million customers. AT&T said the data exposed did not include sensitive information, such as credit card or Social Security numbers, or account passwords, but was limited to “Customer Proprietary Network Information” (CPNI), such as the number of lines on an account. Certain questions may be coming to mind right now, like “What the heck is CPNI?” And, ‘If it’s so ‘customer proprietary,’ why is AT&T sharing it with marketers?” Also maybe, “What can I do about it?” Read on for answers to all three questions. AT&T’s disclosure said the information exposed included customer first name, wireless account number, wireless phone number and email address….According to a succinct CPNI explainer at TechTarget, CPNI is private and protected information that cannot be used for advertising or marketing directly. “An individual’s CPNI can be shared with other telecommunications providers for network operating reasons,” wrote TechTarget’s Gavin Wright. “So, when the individual first signs up for phone service, this information is automatically shared by the phone provider to partner companies.” Is your mobile Internet usage covered by CPNI laws? That’s less clear, as the CPNI rules were established before mobile phones and wireless Internet access were common. TechTarget’s CPNI primer explains: “Under current U.S. law, cellphone use is only protected as CPNI when it is being used as a telephone. During this time, the company is acting as a telecommunications provider requiring CPNI rules. Internet use, websites visited, search history or apps used are not protected CPNI because the company is acting as an information services provider not subject to these laws.” Hence, the carriers can share and sell this data because they’re not explicitly prohibited from doing so. All three major carriers say they take steps to anonymize the customer data they share, but researchers have shown it is not terribly difficult to de-anonymize supposedly anonymous web-browsing data. “Your phone, and consequently your mobile provider, know a lot about you,” wrote Jack Morse for Mashable. “The places you go, apps you use, and the websites you visit potentially reveal all kinds of private information — e.g. religious beliefs, health conditions, travel plans, income level, and specific tastes in pornography. This should bother you.”Happily, all of the U.S. carriers are required to offer customers ways to opt out of having data about how they use their devices shared with marketers. Here’s a look at some of the carrier-specific practices and opt-out options…”