Unusual Activity Detected: What’s Really Happening Behind the Scenes

Have you ever received an email saying your account has been disabled due to “unusual activity”? ⚠️📩

If yes, that was likely a precaution your bank took against potential fraud. And yes, that could be the result of an enumeration attack.

Scammers today don’t just rely on phishing. They’re now using automated tools to guess your 16-digit card number, CVV, and expiry date to find valid combinations.

Here's how it works:

1️⃣ All payment cards begin with a Bank Identification Number (BIN), usually the first six digits. These identify the issuing bank and card type (e.g. Visa or Mastercard). Using a valid BIN, attackers generate thousands of possible card numbers and begin testing them.

2️⃣ They test these numbers in bulk often through online payment forms or small transactions. If a site responds with “invalid CVV” or “expired card” the attacker then knows that the card number is real.  Now they just need to figure out the right CVV or expiry date.

3️⃣ Once they get a match, they can attempt to use the card for purchases. Worse, they can sell the validated card details on the dark web.

These attacks also affect the platforms you use, and not just your card. For example, scammers may try to log into fintech apps or online banking by cycling through thousands of email and password combinations 🔄

If you use the same password across different services and one of those gets leaked, you could become an easy target 💰🥷🎯

That’s why financial services are constantly improving their defences, from fraud detection to stricter security checks, even if it means temporarily freezing your account to keep it safe.

💙 BigPay gives you the ability to take action quickly– our own freezing mechanism is built in the app.

This means you have the power to freeze your card instantly if something feels off. Let’s say you get a notification for a transaction you don’t recognise, instead of panicking, you can immediately freeze your card from the BigPay app to stop further activity. Once you’re confident everything is secure, just unfreeze it with a tap and continue using your card as usual. It's a simple but powerful way to stay in control especially in situations when time is critical.

At the end of the day, these security measures aren’t meant to inconvenience you, they’re meant to protect you.

Enumeration attacks are fast, automated, and often hard to detect until it’s too late ⚠️😫

However, by turning on two-factor authentication, avoiding password reuse, keeping an eye on your bank notifications or any “unusual activity” alerts, you can help stop fraud in its tracks. So, if your bank ever hits pause on your account, it’s likely because something suspicious is spotted before it turns into real damage. 

Enumeration attacks may not be as visible as phishing scams, but they’re a major threat in today’s digital banking world. The more you know, the safer your money stays.

Need help or have questions?

You can always check out our FAQs or chat with us directly via the BigPay app for support 💙