Why SMS 2FA Is Risky for Super App Authentication

Every great security approach starts by learning from past failures.

One of the biggest security mistakes that continues to haunt the digital world is SMS-based Two-Factor Authentication (2FA). It may have been a groundbreaking innovation when first introduced, but today, it is one of the weakest links in securing online accounts.

If you’re building a No-Code Super App, you must ensure that end-users—who may not be security experts—are protected from the start. That means SMS 2FA should never be an option.

The Rise and Fall of SMS 2FA

It all started with AT&T Bell Labs in 1990. Concerned with securing telecommunications and digital transactions, researchers developed what we now know as SMS-based 2FA.

By 1997, AT&T secured US Patent 5708422A for a “Transaction Authorization and Alert System”. The concept was simple:

“An automated method for alerting a customer that a transaction is being initiated and for authorizing the transaction based on confirmation/approval.”

For a while, it worked. Tech giants Microsoft and Google adopted SMS 2FA, and soon, startups followed suit.

But AT&T never made money from the patent itself. Instead, they profited from something far more profitable: SMS traffic fees. The more companies used SMS 2FA, the more carriers charged for:

Enterprise SMS services
Mobile plan usage
International roaming charges

Yet, despite its early success, cracks started to appear. SMS 2FA wasn’t as secure as people believed.

1️⃣ SIM Swap Attacks: When Your Number Becomes Someone Else’s

Imagine waking up one day, and your phone stops working. No calls. No messages. Just silence.

Unbeknownst to you, a hacker has taken over your phone number.

How?

They gather your personal information from public records, phishing attacks, or data breaches.
They call your mobile carrier pretending to be you and request a SIM swap.
The carrier deactivates your SIM and activates the hacker’s new one.
The hacker resets your passwords using SMS 2FA—because the code is now sent to their phone.

📌 Example: This is exactly how Twitter CEO Jack Dorsey was hacked in 2019. Attackers took over his phone number and posted offensive tweets from his account.

2️⃣ Phishing Attacks: Tricking You into Handing Over Your 2FA Code

Hackers have an old trick: If they can’t break security, they’ll make you give it to them voluntarily.

Phishing attacks work like magic. You receive an email, claiming:

🚨 “Unusual activity detected on your account! Click here to verify.”

You click. A familiar login page appears. You enter your username, password… and then your 2FA code.

What you don’t realize? The website was fake. The hacker now has everything they need.

📌 Example: In 2018, Google employees were targeted in a sophisticated phishing attack. The breach was so successful that Google abandoned SMS 2FA and switched to security keys.

3️⃣ Man-in-the-Middle Attacks: When Hackers Eavesdrop on Your SMS

SMS messages travel through telecom networks that were never designed for modern security.

That’s why hackers exploit SS7 protocol vulnerabilities—a loophole in global telecom infrastructure that allows them to intercept text messages remotely.

Other hackers use fake Wi-Fi networks. You connect to “Free Starbucks Wi-Fi”, thinking it’s legit, but instead, it’s a hacker’s trap. Everything you do online—including receiving your 2FA code—is visible to them.

📌 Example: In 2017, hackers used SS7 vulnerabilities to steal money from German bank customers by intercepting SMS 2FA codes.

4️⃣ Delayed & Failed SMS Deliveries: The Frustration Factor

Sometimes, security flaws don’t come from hackers. They come from technology itself.

You need urgent access to your account. You request an SMS code. It never arrives.

Or worse—you request it ten times, get locked out, and receive all the messages at once… an hour later.

This isn’t just frustrating—it’s a serious usability issue.

🔥 The Future of Secure Authentication in No-Code Super Apps

If SMS 2FA is dead, what should replace it?

✅ Authenticator Apps (Google Authenticator, Authy)

Instead of relying on SMS, use a Time-Based One-Time Password (TOTP) that changes every 30 seconds.

✅ Magic Links (Email Authentication)

Instead of passwords or codes, users receive a secure login link via email.

✅ Single Sign-On (Google, Apple, Microsoft)

Leverage OAuth authentication, allowing users to log in with existing accounts securely.

Final Thoughts: The Security Standard for Super Apps

Security isn’t about keeping things hidden. It’s about making sure your users can’t make mistakes.

The right security approach for No-Code Super Apps:

🔹 Never offer SMS 2FA as an option.
🔹 Build secure authentication directly inside the platform.
🔹 Give users safer alternatives, pre-integrated.

At Acenji, we don’t just say we’re secure—we build security by design.

If you’re building a No-Code Super App, don’t make the same mistakes of the past.

Build it right. Build it securely. Build it like Acenji.