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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.
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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. In addition, a small percentage of customer records also exposed the rate plan name, past due amounts, monthly payment amounts and minutes used.
CPNI refers to customer-specific “metadata” about the account and account usage, and may include:
-Called phone numbers
-Time of calls
-Length of calls
-Cost and billing of calls
-Service features
-Premium services, such as directory call assistance
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.
AT&T’s policy says it shares device or “ad ID”, combined with demographics including age range, gender, and ZIP code information with third parties which explicitly include advertisers, programmers, and networks, social media networks, analytics firms, ad networks and other similar companies that are involved in creating and delivering advertisements.
AT&T said the data exposed on 9 million customers was several years old, and mostly related to device upgrade eligibility. This may sound like the data went to just one of its partners who experienced a breach, but in all likelihood it also went to hundreds of AT&T’s partners.
AT&T’s CPNI opt-out page says it shares CPNI data with several of its affiliates, including WarnerMedia, DirecTV and Cricket Wireless. Until recently, AT&T also shared CPNI data with Xandr, whose privacy policy in turn explains that it shares data with hundreds of other advertising firms. Microsoft bought Xandr from AT&T last year.
According to the Electronic Privacy Information Center (EPIC), T-Mobile seems to be the only company out of the big three to extend to all customers the rights conferred by the California Consumer Privacy Act (CCPA).
EPIC says T-Mobile customer data sold to third parties uses another unique identifier called mobile advertising IDs or “MAIDs.” T-Mobile claims that MAIDs don’t directly identify consumers, but under the CCPA MAIDs are considered “personal information” that can be connected to IP addresses, mobile apps installed or used with the device, any video or content viewing information, and device activity and attributes.
T-Mobile customers can opt out by logging into their account and navigating to the profile page, then to “Privacy and Notifications.” From there, toggle off the options for “Use my data for analytics and reporting” and “Use my data to make ads more relevant to me.”
Verizon’s privacy policy says it does not sell information that personally identities customers (e.g., name, telephone number or email address), but it does allow third-party advertising companies to collect information about activity on Verizon websites and in Verizon apps, through MAIDs, pixels, web beacons and social network plugins.
According to Wired.com’s tutorial, Verizon users can opt out by logging into their Verizon account through a web browser or the My Verizon mobile app. From there, select the Account tab, then click Account Settings and Privacy Settings on the web. For the mobile app, click the gear icon in the upper right corner and then Manage Privacy Settings.
On the privacy preferences page, web users can choose “Don’t use” under the Custom Experience section. On the My Verizon app, toggle any green sliders to the left.
EPIC notes that all three major carriers say resetting the consumer’s device ID and/or clearing cookies in the browser will similarly reset any opt-out preferences (i.e., the customer will need to opt out again), and that blocking cookies by default may also block the opt-out cookie from being set.
T-Mobile says its opt out is device-specific and/or browser-specific. “In most cases, your opt-out choice will apply only to the specific device or browser on which it was made. You may need to separately opt out from your other devices and browsers.”
Both AT&T and Verizon offer opt-in programs that gather and share far more information, including device location, the phone numbers you call, and which sites you visit using your mobile and/or home Internet connection. AT&T calls this their Enhanced Relevant Advertising Program; Verizon’s is called Custom Experience Plus.
In 2021, multiple media outlets reported that some Verizon customers were being automatically enrolled in Custom Experience Plus — even after those customers had already opted out of the same program under its previous name — “Verizon Selects.”
If none of the above opt out options work for you, at a minimum you should be able to opt out of CPNI sharing by calling your carrier, or by visiting one of their stores.
Why should you opt out of sharing CPNI data? For starters, some of the nation’s largest wireless carriers don’t have a great track record in terms of protecting the sensitive information that you give them solely for the purposes of becoming a customer — let alone the information they collect about your use of their services after that point.
In January 2023, T-Mobile disclosed that someone stole data on 37 million customer accounts, including customer name, billing address, email, phone number, date of birth, T-Mobile account number and plan details. In August 2021, T-Mobile acknowledged that hackers made off with the names, dates of birth, Social Security numbers and driver’s license/ID information on more than 40 million current, former or prospective customers who applied for credit with the company.
Last summer, a cybercriminal began selling the names, email addresses, phone numbers, SSNs and dates of birth on 23 million Americans. An exhaustive analysis of the data strongly suggested it all belonged to customers of one AT&T company or another. AT&T stopped short of saying the data wasn’t theirs, but said the records did not appear to have come from its systems and may be tied to a previous data incident at another company.
However frequently the carriers may alert consumers about CPNI breaches, it’s probably nowhere near often enough. Currently, the carriers are required to report a consumer CPNI breach only in cases “when a person, without authorization or exceeding authorization, has intentionally gained access to, used or disclosed CPNI.”
But that definition of breach was crafted eons ago, back when the primary way CPNI was exposed was through “pretexting,” such when the phone company’s employees are tricked into giving away protected customer data.
In January, regulators at the U.S. Federal Communications Commission (FCC) proposed amending the definition of “breach” to include things like inadvertent disclosure — such as when companies expose CPNI data on a poorly-secured server in the cloud. The FCC is accepting public comments on the matter until March 24, 2023.
While it’s true that the leak of CPNI data does not involve sensitive information like Social Security or credit card numbers, one thing AT&T’s breach notice doesn’t mention is that CPNI data — such as balances and payments made — can be abused by fraudsters to make scam emails and text messages more believable when they’re trying to impersonate AT&T and phish AT&T customers.
The other problem with letting companies share or sell your CPNI data is that the wireless carriers can change their privacy policies at any time, and you are assumed to be okay with those changes as long as you keep using their services.
For example, location data from your wireless device is most definitely CPNI, and yet until very recently all of the major carriers sold their customers’ real-time location data to third party data brokers without customer consent.
What was their punishment? In 2020, the FCC proposed fines totaling $208 million against all of the major carriers for selling their customers’ real-time location data. If that sounds like a lot of money, consider that all of the major wireless providers reported tens of billions of dollars in revenue last year (e.g., Verizon’s consumer revenue alone was more than $100 billion last year).
If the United States had federal privacy laws that were at all consumer-friendly and relevant to today’s digital economy, this kind of data collection and sharing would always be opt-in by default. In such a world, the enormously profitable wireless industry would likely be forced to offer clear financial incentives to customers who choose to share this information.
But until that day arrives, understand that the carriers can change their data collection and sharing policies when it suits them. And regardless of whether you actually read any notices about changes to their privacy policies, you will have agreed to those changes as long as you continue using their service.
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Twice in the past month KrebsOnSecurity has heard from readers who had their accounts at big-three credit bureau Experian hacked and updated with a new email address that wasn’t theirs. In both cases the readers used password managers to select strong, unique passwords for their Experian accounts. Research suggests identity thieves were able to hijack the accounts simply by signing up for new accounts at Experian using the victim’s personal information and a different email address.
John Turner is a software engineer based in Salt Lake City. Turner said he created the account at Experian in 2020 to place a security freeze on his credit file, and that he used a password manager to select and store a strong, unique password for his Experian account.
Turner said that in early June 2022 he received an email from Experian saying the email address on his account had been changed. Experian’s password reset process was useless at that point because any password reset links would be sent to the new (impostor’s) email address.
An Experian support person Turner reached via phone after a lengthy hold time asked for his Social Security Number (SSN) and date of birth, as well as his account PIN and answers to his secret questions. But the PIN and secret questions had already been changed by whoever re-signed up as him at Experian.
“I was able to answer the credit report questions successfully, which authenticated me to their system,” Turner said. “At that point, the representative read me the current stored security questions and PIN, and they were definitely not things I would have used.”
Turner said he was able to regain control over his Experian account by creating a new account. But now he’s wondering what else he could do to prevent another account compromise.
“The most frustrating part of this whole thing is that I received multiple ‘here’s your login information’ emails later that I attributed to the original attackers coming back and attempting to use the ‘forgot email/username’ flow, likely using my SSN and DOB, but it didn’t go to their email that they were expecting,” Turner said. “Given that Experian doesn’t support two-factor authentication of any kind — and that I don’t know how they were able to get access to my account in the first place — I’ve felt very helpless ever since.”
Arthur Rishi is a musician and co-executive director of the Boston Landmarks Orchestra. Rishi said he recently discovered his Experian account had been hijacked after receiving an alert from his credit monitoring service (not Experian’s) that someone had tried to open an account in his name at JPMorgan Chase.
Rishi said the alert surprised him because his credit file at Experian was frozen at the time, and Experian did not notify him about any activity on his account. Rishi said Chase agreed to cancel the unauthorized account application, and even rescinded its credit inquiry (each credit pull can ding your credit score slightly).
But he never could get anyone from Experian’s support to answer the phone, despite spending what seemed like eternity trying to progress through the company’s phone-based system. That’s when Rishi decided to see if he could create a new account for himself at Experian.
“I was able to open a new account at Experian starting from scratch, using my SSN, date of birth and answering some really basic questions, like what kind of car did you take out a loan for, or what city did you used to live in,’ Rishi said.
Upon completing the sign-up, Rishi noticed that his credit was unfrozen.
Like Turner, Rishi is now worried that identity thieves will just hijack his Experian account once more, and that there is nothing he can do to prevent such a scenario. For now, Rishi has decided to pay Experian $25.99 a month to more closely monitor his account for suspicious activity. Even using the paid Experian service, there were no additional multi-factor authentication options available, although he said Experian did send a one-time code to his phone via SMS recently when he logged on.
“Experian now sometimes does require MFA for me if I use a new browser or have my VPN on,” Rishi said, but he’s not sure if Experian’s free service would have operated differently.
“I get so angry when I think about all this,” he said. “I have no confidence this won’t happen again.”
In a written statement, Experian suggested that what happened to Rishi and Turner was not a normal occurrence, and that its security and identity verification practices extend beyond what is visible to the user.
“We believe these are isolated incidents of fraud using stolen consumer information,” Experian’s statement reads. “Specific to your question, once an Experian account is created, if someone attempts to create a second Experian account, our systems will notify the original email on file.”
“We go beyond reliance on personally identifiable information (PII) or a consumer’s ability to answer knowledge-based authentication questions to access our systems,” the statement continues. “We do not disclose additional processes for obvious security reasons; however, our data and analytical capabilities verify identity elements across multiple data sources and are not visible to the consumer. This is designed to create a more positive experience for our consumers and to provide additional layers of protection. We take consumer privacy and security seriously, and we continually review our security processes to guard against constant and evolving threats posed by fraudsters.”
KrebsOnSecurity sought to replicate Turner and Rishi’s experience — to see if Experian would allow me to re-create my account using my personal information but a different email address. The experiment was done from a different computer and Internet address than the one that created the original account years ago.
After providing my Social Security Number (SSN), date of birth, and answering several multiple choice questions whose answers are derived almost entirely from public records, Experian promptly changed the email address associated with my credit file. It did so without first confirming that new email address could respond to messages, or that the previous email address approved the change.
Experian’s system then sent an automated message to the original email address on file, saying the account’s email address had been changed. The only recourse Experian offered in the alert was to sign in, or send an email to an Experian inbox that replies with the message, “this email address is no longer monitored.”
After that, Experian prompted me to select new secret questions and answers, as well as a new account PIN — effectively erasing the account’s previously chosen PIN and recovery questions. Once I’d changed the PIN and security questions, Experian’s site helpfully reminded me that I have a security freeze on file, and would I like to remove or temporarily lift the security freeze?
To be clear, Experian does have a business unit that sells one-time password services to businesses. While Experian’s system did ask for a mobile number when I signed up a second time, at no time did that number receive a notification from Experian. Also, I could see no option in my account to enable multi-factor authentication for all logins.
How does Experian differ from the practices of Equifax and TransUnion, the other two big consumer credit reporting bureaus? When KrebsOnSecurity tried to re-create an existing account at TransUnion using my Social Security number, TransUnion rejected the application, noting that I already had an account and prompting me to proceed through its lost password flow. The company also appears to send an email to the address on file asking to validate account changes.
Likewise, trying to recreate an existing account at Equifax using personal information tied to my existing account prompts Equifax’s systems to report that I already have an account, and to use their password reset process (which involves sending a verification email to the address on file).
KrebsOnSecurity has long urged readers in the United States to place a security freeze on their files with the three major credit bureaus. With a freeze in place, potential creditors can’t pull your credit file, which makes it very unlikely anyone will be granted new lines of credit in your name. I’ve also advised readers to plant their flag at the three major bureaus, to prevent identity thieves from creating an account for you and assuming control over your identity.
The experiences of Rishi, Turner and this author suggest Experian’s practices currently undermine both of those proactive security measures. Even so, having an active account at Experian may be the only way you find out when crooks have assumed your identity. Because at least then you should receive an email from Experian saying they gave your identity to someone else.
In April 2021, KrebsOnSecurity revealed how identity thieves were exploiting lax authentication on Experian’s PIN retrieval page to unfreeze consumer credit files. In those cases, Experian failed to send any notice via email when a freeze PIN was retrieved, nor did it require the PIN to be sent to an email address already associated with the consumer’s account.
A few days after that April 2021 story, KrebsOnSecurity broke the news that an Experian API was exposing the credit scores of most Americans.
Emory Roan, policy counsel for the Privacy Rights Clearinghouse, said Experian not offering multi-factor authentication for consumer accounts is inexcusable in 2022.
“They compound the problem by gating the recovery process with information that’s likely available or inferable from third party data brokers, or that could have been exposed in previous data breaches,” Roan said. “Experian is one of the largest Consumer Reporting Agencies in the country, trusted as one of the few essential players in a credit system Americans are forced to be part of. For them to not offer consumers some form of (free) MFA is baffling and reflects extremely poorly on Experian.”
Nicholas Weaver, a researcher for the International Computer Science Institute at University of California, Berkeley, said Experian has no real incentive to do things right on the consumer side of its business. That is, he said, unless Experian’s customers — banks and other lenders — choose to vote with their feet because too many people with frozen credit files are having to deal with unauthorized applications for new credit.
“The actual customers of the credit service don’t realize how much worse Experian is, and this isn’t the first time Experian has screwed up horribly,” Weaver said. “Experian is part of a triopoly, and I’m sure this is costing their actual customers money, because if you have a credit freeze that gets lifted and somebody loans against it, it’s the lender who eats that fraud cost.”
And unlike consumers, he said, lenders do have a choice in which of the triopoly handles their credit checks.
“I do think it’s important to point out that their real customers do have a choice, and they should switch to TransUnion and Equifax,” he added.
More greatest hits from Experian:
2017: Experian Site Can Give Anyone Your Credit Freeze PIN
2015: Experian Breach Affects 15 Million Customers
2015: Experian Breach Tied to NY-NJ ID Theft Ring
2015: At Experian, Security Attrition Amid Acquisitions
2015: Experian Hit With Class Action Over ID Theft Service
2014: Experian Lapse Allowed ID Theft Service Access to 200 Million Consumer Records
2013: Experian Sold Consumer Data to ID Theft Service
Update, 10:32 a.m.: Updated the story to clarify that while Experian does sometimes ask users to enter a one-time code sent via SMS to the number on file, there does not appear to be any option to enable this on all logins.
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