From end-to-end encrypted messaging apps to secure email providers, we have plenty of ways to protect our communication and data. Yet, traditional phone calls and SMS remain vulnerable at the telecom network level—leaving a major security gap that the industry has failed to close.
Commercial cell phone carriers use outdated, easily exploitable security protocols that have exposed consumers to countless data breaches. In a 2024 SEC filing, AT&T revealed that a security breach that took place between May 1 and October 31, 2022, as well as on January 2, 2023, exfiltrated the “records of calls and texts of nearly all of AT&T’s wireless customers.”
Other carriers are no less immune to security vulnerabilities. Besides dozens of individual data breaches, major carriers, including Verizon, T-Mobile, and Lumen, fell victim to Chinese hacking group Salt Typhoon.
As if this isn’t concerning enough, carriers routinely profit off of consumer data by selling it to third parties. This practice led to some serious repercussions for many top carriers when the FCC fined them $200 million in 2024.
The takeaway? Traditional carriers aren’t nearly as secure as they need to be. They operate on a trust-based system but don’t justify the trust customers put into them.
The question is: Do you have better options? Let’s find out.
The Fundamental Problem With Major Phone Carriers in the U.S.
To understand why major telcos are susceptible to frequent and elaborate attacks, you need to familiarize yourself with the key issues in the traditional telco architecture:
- Interoperability over security
- Data pooling
- Legacy signaling protocols
Interoperability Over Security
Telco systems are prime hacking targets because they prioritize interoperability over security. To ensure seamless and uninterrupted roaming, telcos must blindly trust one another. However, once a malicious actor breaches the system, they can access massive amounts of user data.
Data Pooling
Traditional carriers don’t just collect excessive personal data—they aggregate it across multiple sources to create detailed user profiles. This includes data from your carrier, your home internet provider, entertainment companies, ad agencies, and other third parties, all sharing and selling data to one another to create a more complete picture of who you are. The result? A highly valuable record of who you are, what you do, and where you go—perfect for surveillance, ad targeting, or exploitation.
Legacy Signaling Protocols
Mobile carriers rely on outdated telecommunication protocols, like SS7 and Diameter, which were never designed with security in mind.
SS7 was developed during the 70s, and it was last revised in 1993. This fact alone attests to why attacks and data breaches are so common—carriers are relying on a protocol that hasn’t been updated for 30+ years.
Diameter, on the other hand, was meant to enhance SS7 as its successor for 4G LTE, VoLTE, and 5G networks. Still, it inherited the protocol’s main flaw—a trust-based system without comprehensive authentication mechanisms or user control.
In practical terms, these architecture-level vulnerabilities allow malicious parties to:
- Track the user’s location
- Break into the networks and get access to users’ sensitive information
- Extract the international mobile subscriber identity (IMSI), which uniquely identifies each user of a cellular network
Is Your Mobile Carrier Actually Secure? Analyzing 7 Top Options
To help you understand the exact level of data protection you get with your carrier, the following sections will break down the security features and concerns of seven leading U.S. telcos and MVNOs:
- AT&T
- Verizon
- T-Mobile
- Visible
- Mint Mobile
- Xfinity
- Boost Mobile
1. AT&T
AT&T provides regular security features to reduce the risk of data breaches:
- Two-factor authentication (2FA) for online account access
- Optional account passcodes
- ActiveArmorSM security that helps block spam calls and notifies of data breaches
These features safeguard user data to an extent and focus on preventing SIM swaps—a common account takeover attack that ports a user’s phone number to an attacker’s SIM. However, the security mechanism isn’t too effective as AT&T employees could technically bypass it and allow hackers to perform a sim swap.
AT&T shares aggregated user data with third parties by default, which is an unfortunate industry standard. Worse yet, the carrier was found to illegally share users’ location data with third parties, which resulted in a $57 million fine by the FCC.
AT&T has also fallen victim to many data breaches over the years despite its security features. We previously mentioned a particularly dangerous one, when the data of over 70 million current and former customers ended up on the Dark Web.
The data included highly sensitive information like users’ Social Security numbers (SSN), which exposed customers to further issues like an increased risk of identity theft.
Several account security options
SIM swap prevention features
Shares and sells data to third parties
Encountered severe data breaches
2. Verizon
Over the past few years, Verizon has released several security measures aimed at minimizing the risks of SIM swapping and similar attacks. The most effective one is Number Lock, which lets customers freeze their phone number to prevent it from being ported out without an additional layer of verification.
Another useful feature is the Number Transfer PIN, which is required when porting a line to another carrier. The user must generate the PIN through the app or by dialing #PORT, which complicates attackers’ takeover efforts.
Unfortunately, this doesn’t make Verizon significantly safer than AT&T. Both AT&T and Verizon employees were offered a $300 bribe per successful SIM swap, proving that the consumers’ accounts aren’t safe from internal threats. The company was also involved in the location-sharing incident, which confirmed its murky data protection practices.
To make the issue worse, Verizon has been found to share customer browsing and usage data with advertisers to personalize ads. While the carrier lets consumers opt out, there have been reports of it overriding users’ preferences and collecting data nevertheless.
While Verizon hasn’t reported as many significant security breaches as AT&T in the past few years, the data privacy issue remains due to the carrier’s inclination toward data collection and sharing.
Browsing and usage data collection
Misleading and ineffective opt-out policies
Keep reading: Explore our AT&T vs. Verizon guide and discover how they measure up.
3. T-Mobile
T-Mobile’s account and data protection features are comparable to those of its competitors and include:
- PIN/passcode required for all major account changes (e.g., number port-outs)
- Complimentary Account Takeover Protection add-on
- Scam call blocking and reporting
The company took an extra step by pledging $150 million toward a two-year security upgrade initiative alongside the formation of a dedicated Cybersecurity Transformation Office reporting directly to the carrier’s CEO.
While these initiatives may seem commendable, the reason behind them is quite disturbing. Namely, T-Mobile suffered one of the largest telco breaches to date in August 2021, when an attacker used an API to extract the data of over 79 million users. The data included some of the most sensitive information, specifically:
- SSNs
- Names
- Dates of birth
- Driver’s license/ID details
Despite T-Mobile’s efforts to safeguard data following the incident, several major attacks occurred after it, with the most recent ones happening in 2023.
Data and account protection features
Dedicated internal Cybersecurity Transformation Office
Victim of severe cybersecurity attacks
Seemingly ineffective data protection initiatives
4. Visible
Verizon’s online-only carrier Visible gained popularity because of its budget-friendly unlimited plans. As users can only manage accounts through the app and website, the carrier safeguards them through several security measures, such as:
- Multi-factor authentication (MFA)
- Passwordless login
- PIN for account changes
This wasn’t always the case—Visible implemented many of its measures following the 2021 security incident that involved a series of account takeovers caused by credential stuffing. The attack allowed hackers to change users’ information and exploit their credit cards for mobile phone purchases.
As for privacy, Visible is aligned with Verizon’s policies, which means user data is routinely collected and used for ad personalization. While there haven’t been any noteworthy incidents since 2021, Visible doesn’t offer significantly more protection than other carriers.
Multi-factor authentication
Passwordless login
Suffered a serious account takeover incident
Privacy practices similar to Verizon’s
5. Mint Mobile
Mint Mobile operates on T-Mobile’s network, though it doesn’t share all of the same security features because it’s a considerably smaller carrier. It offers some standard protection mechanisms, including:
- PIN for porting requests
- IP address blocking
- Notifications of notable account changes
In recent years, Mint Mobile suffered two noteworthy incidents. The first one was in 2021, when an attacker used SIM swapping to port numbers and accessed subscribers’ information like their names, call history, and passwords.
While the attack didn’t have severe consequences because no sensitive data was stolen, the second breach in 2023 was more invasive. Besides names and emails, the hacker stole account details like SIM card identifiers (ICCID) and the phones’ IMEI (unique device number).
Mint Mobile’s privacy practices are comparable to those of major carriers. The company states it might share your data with affiliates for marketing purposes, so consumers don’t get as much privacy as they should.
Porting protection to prevent SIM swapping
No reported incidents involving critical data (e.g., SSNs or credit card information)
ICCIDs and IMEIs leaked in an attack
Data sharing with affiliates
6. Xfinity
Xfinity is a part of Comcast’s ecosystem, so Xfinity Mobile accounts are linked to the cable/internet service account. Much like Visible, the carrier operates as a Mobile Virtual Network Operator (MVNO) and uses Verizon’s network.
With this in mind, Xfinity’s security features are aligned with Comcast’s and Verizon’s—they include:
- Number locking
- Email and text alerts for port-out requests
- Two-factor authentication
Unfortunately, these measures weren’t enough to protect consumers from breaches. In 2022, a hacker managed to circumvent Xfinity’s 2FA and gain access to users’ accounts. In addition to accessing their information, they were able to reset passwords of not only Xfinity accounts but also other services like Gemini and Coinbase.
Privacy-wise, there’s not much to say—Xfinity’s privacy policy is aligned with Comcast’s and outlines the same conditions as other carriers, including data sharing with third parties (which you can opt out of). However, Xfinity is pooling customer data across the home internet and cellular business, which allows them to track customers with far more data.
Port-out alerts
Two-factor authentication
Account takeover incidents
Data pooling and sharing for advertising purposes
7. Boost Mobile
Boost Mobile is a prepaid wireless carrier, so it inherently exposes consumers to fewer risks because it doesn’t require extensive personal details or credit checks. It comes with standard security features like PIN account protection and multi-factor authentication without advanced measures.
While the carrier hasn’t directly fallen victim to cybersecurity attacks, it suffered collateral damage from the attack on its parent company, Dish Network. In 2023, Dish Network was targeted by a ransomware attack that affected around 300,000 consumers, including Boost Mobile customers.
Even though Boost Mobile wasn’t the target, it was the entry point. The ransomware group reportedly gained access to Dish Network’s core system through the Boost Mobile network, which indicates the carrier’s weak IT safeguards.
Less data collection than with major carriers
No direct severe data breaches
Suffered an attack through its parent company
Used as an entry point for a ransomware attack
So, Which Phone Carrier Is the Most Secure in 2026?
It’s evident that most top telcos and MVNOs don’t have airtight practices when it comes to data security and privacy. Legacy carriers continuously fail to eliminate the jarring vulnerabilities in their service, so all of the above options fall short if security really matters to you.
The good news is that there is an exception: Cape.
Cape is an independent mobile carrier built from the ground up on a privacy-first, minimal-trust model. The telco ditches traditional data-hoarding architecture and gives you a premium carrier service free from vulnerabilities like SIM swapping and SS7-based surveillance.
Meet Cape: The Secure Carrier Designed for Today’s Threats
We share the most intimate details of our everyday lives with our cell phones. In order to stay connected, our cell phones share that information with local cell networks, and in turn, those cell networks share our data with each other.
While this system is what makes connectivity possible, it was also built with interoperability as its priority, rather than security. The global cell network is vulnerable to a number of threats, as seen through headlines about major carrier data breaches we see time and time again. When major carriers aren’t losing our sensitive personal data in breaches and hacks, they’re actively selling it to ad networks, data brokers, and third parties.
At Cape, we believe that privacy and security shouldn’t have to be sacrificed for connectivity. That’s why we built our service with privacy principles and security features at its core, including:
Cape eliminates the risk of your sensitive data falling into the wrong hands by not even asking for it. When you make your Cape account, we don’t ask for your name, address, or SSN. We only collect the information that’s necessary to provide the service, and we retain it for the least amount of time possible.
During account creation, you receive a unique 24-word phrase that generates a private key tied to your phone number. This pass phrase is required to move your number to a new device or carrier. Nobody else, not even us at Cape, has access to the phrase, meaning there’s absolutely no way for bad actors to transfer your number to their device, effectively nullifying the possibility of SIM swapping.
Your phone stores an incredible amount of data, which can be accessed through call and text records. Most mobile carriers store your call and text metadata for years, which can easily fall into the wrong hands.
Cape is built to forget, meaning we delete Call Data Records (CDRs) after just 1 day, ensuring nobody can see who you texted or called, track where the communication took place, or access the sensitive information within CDRs.
All SIM cards are accompanied by International Mobile Subscriber IDs (IMSI). These function as unique identifiers devices use to register with cellular networks. Traditional telcos assign fixed IMSIs to user accounts, meaning the carriers, advertisers, hackers, and other bad actors can exploit them to identify and track your device.
Cape patches this security hole by allowing you to automatically rotate your IMSI every 24 hours. In practice, this means you appear as a different subscriber every day, making it much more difficult for anyone to identify your device or track your movements.
Are you tired of spam messages from brands, phone call surveys, and scammers trying to trick you into sharing sensitive information over the phone? The reason why most people are exposed to these nuisances is that we are often required to share our phone numbers with retailers, websites, apps, and service providers.
While messages and phone calls can be annoying, what’s worse is that your number can easily become a target for data brokers and bad actors. That’s why many people turn to VoIP numbers as secondary lines. VoIPs are a decent option, but they don’t fully solve the issue—they are not encrypted, you can’t use them for 2FA, and they’re an additional cost each month.
When you sign up for Cape, you get two free additional SMS/MMS lines that are middle-to-end encrypted. This allows you to use Secondary Numbers for online shopping, signing up for services and discounts, and receiving secure OTPs, while your primary phone number is reserved for friends and family.
6. Network Lock
Traditional cellular networks were designed for interoperability, not security. Outdated and legacy network protocols like SS7 have vulnerabilities that allow attackers to hack in and track your location, intercept your calls and texts, and steal sensitive information.
Cape’s Network Lock uses a proprietary signaling proxy to verify that your device’s physical location matches the network it’s trying to attach to. If anything looks suspicious, like a mismatched location, we block the connection.
Voicemails can reveal more than you think, from personal messages to authentication codes, yet most voicemail systems are outdated and unencrypted.
Cape encrypts your voicemails so that only you can access them.
To access phone service while traveling abroad, your phone typically needs to connect to local telecom providers. The trouble is, there’s no guarantee all networks are secure, and not every government treats privacy the same.
Cape doesn’t leave anything to chance. We let you route traffic through our U.S.-based mobile core, so you can safely use international data roaming without exposing your identity or sharing sensitive data or communications with foreign carriers.
With Cape, you get up to 15 GB per month of international roaming, included in your monthly plan.
Get Started With Cape Today
If you’re ready to make a switch from legacy telcos to America's privacy-first mobile carrier, visit cape.co/get-cape.
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