Has Your Credit Card Number Been Leaked? (2024)

As data breaches become increasingly common, many people are falling victim to credit card leaks. Unfortunately, most don't find out that they were part of a breach until notified by their financial institutions.

But how are credit cards leaked in the first place? Are there ways to proactively find out if you are part of a credit card breach to minimize damage and protect your sensitive data?

How Are Credit Cards Leaked?

A security incident such as a data breach affecting a bank or any other database where your credit card or personal data is stored can expose your credit card information to the world. Once that happens, you can become part of a data leak. Such information is often sold on the dark web.

Here are some common methods through which credit cards can be leaked.

Phishing Emails

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The sole purpose of phishing emails is to dupe users into clicking fraudulent links or downloading malicious attachments. The links seem credible and familiar but may ask users to click on further dubious links or ask them to enter account information.

Public Wi-Fi Networks

While it's nice to be able to access public Wi-Fi when you are grabbing coffee or waiting at an airport, there's always some risk involved.

Public networks are susceptible to data breaches and Wi-Fi frag attacks. If you punch in your sensitive details or access your bank website while using public Wi-Fi, you can easily fall victim to such attacks.

Tip:Install a VPN on your device if you often use the internet in public.


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While skimming mostly affects older card types with magnetic strips, this method can still cause a lot of issues.

Skimming usually happens when a thief steals your credit card number while you are making a transaction and then uses it to create a counterfeit card or carry out online transactions that don’t require a physical card. Sometimes, device skimmers are also used in places such as unattended terminals to steal card data.

Tip: Transition to EMV chip cards if you haven't already as they prevent device skimmers from interpreting data. It's worth paying special attention to unattended payment booths and terminals. If you see something unusual in the card slot, refrain from using it and alert an employee if possible.

Major Data Breaches

Large organizations like retail businesses and banks may fall victim to data breaches which can put you at risk of credit card leaks as well.

One of the biggest data breaches of modern times hit Capital One in 2019 and affected tens of millions of consumers.

Insider Attacks

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Insider attacks happen when a privileged user like an admin or even a disgruntled employee with access to a cardholder database decides to exfiltrate the data. While various measures (such as logging) exist in the banking system to prevent that from happening, the reality is that anyone with access can tamper with user logs if they wanted to.

Credit card leaks owing to insider attacks are minimal but there is always a possibility that they can happen.

Related: The Risk of Compromised Credentials and Insider Threats in the Workplace

Cardholder Data in Logs

Log files are much less protected than a cardholder database. Occasionally, a developer could make a mistake that could get past review and push thousands of credit card numbers into log files instead.

Once that happens, it can be very easy for attackers who are on the lookout, to find credit card numbers in the logs files.


Formjacking is a way of collecting credit card data before it enters a secure environment. This type of attack uses script injection (via compromised static resources) to collect the data as the user is typing it.

Have Your Credit Card Details Been Leaked?

Worried about your credit card information being leaked? Here are some tell-tale signs to look out for.

Strange Purchases on Your Account

Seeing unknown purchases on your bank account statement is a big red flag indicating that your credit card might have been breached.

Credit card leaks can happen at any time, so it's important to keep checking your bank account regularly to stay on top of things.

Small Charges on Your Account

Most credit card thieves start off by making small purchases on your credit card to avoid triggering any red flags. A trickle of small charges that look unfamiliar is a potential sign that someone has been using your credit card for purchases.

Unfamiliar Company Names on Your Statement

If an unfamiliar name appears on your statement for the payments you have made, then you should contact your credit card company to dispute the charges as soon as possible.

Noticing a payment made to a company name that you're not familiar with could signify a credit card leak.

A Lower Available Credit Balance

Unexplained pending charges that show a diminished credit line hint that your credit card has been leaked or tampered with.

If there are no justifiable big item purchases on your end then you should always investigate the real reason behind the change in your available credit.

How to Protect Yourself Against Credit Card Leaks

It's always best to be proactive and mitigate any risks associated with your credit cards. The following strategies can help.

Use Secure Websites Only

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It is crucial that you avoid entering personal information on unsecured websites. Look for a tiny padlock icon before the website address in the URL to ensure the site that you are trying to reach is encrypted using the secure HTTPS version of the internet.

While not a guarantee, it does provide some assurance that the website is practicing a higher level of security.

Related: Does HTTPS Protect Data in Transit?

Don’t Give Your Account Number Over the Phone

Never give out your credit card or account number on the phone unless you are sure of the caller's legitimacy. Be extra cautious of any random scam calls where a caller asks you for your credit card information.

Simply put: don't share private details over the phone!

Check Credit Card Statements Regularly

Checking your statements regularly is the best way to protect against credit card leaks and fraud. As a rule of thumb, you should check your statements at least once a month.

Inform your card issuer or financial institution immediately if you notice any suspicious charges.

Keep an Eye on Your Card During In-Person Transactions

Never let any employee at a restaurant or a retail store take your credit card and walk away with it. Once out of sight, the person holding your card can write down your card number, expiration date, and security code—or make contactless payments!

Be Proactive and Limit the Damage

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Much of preventing a data breach entails limiting the damage after your credit card details have been compromised.

Time is of the essence once you realize that your credit card might be tampered with. So act fast and freeze your breached credit card.

At the same time, keep monitoring your financial statements, and sign up for identity theft and monitoring services.

Just remember that, by applying mitigation strategies before damage strikes, you will not only limit the harm to your credit cards but can also prevent future attacks.

  • Security
  • Security Breach
  • Scams

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Has Your Credit Card Number Been Leaked? (2024)


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