Why payment gateways break in the real world
Payment systems are incredibly complex. You have merchants, buyers, banks, and ledgers. They all talk to each other. Automated scanners cannot understand how the money moves between them. Scanners miss the logical flaws.
We manually test the rules. We trace the money from the first click to the final payout. We find the real bugs that cost you cash.
The anatomy of a payment gateway attack
Let us look at how a hacker actually steals from you. They do not break your encryption. They break your logic.
A hacker goes to your checkout page. They buy a laptop for $1,000. Your app sends them to the payment provider. The hacker pays for the laptop. But right before the payment provider sends the "Success" message back to your server, the hacker intercepts the message.
The hacker changes the message. They tell your server: "I just paid $10,000." Your server believes the message. It gives the hacker the laptop and a $9,000 credit balance.
This is a webhook tampering attack. Scanners never find this. Only a human penetration tester finds this. We test your server to make sure it never trusts a tampered message.
What we test to stop fraud
We attack the exact spots where hackers try to break in. Here is our test plan for your payment gateway.
Webhook spoofing and replay
Hackers send fake "payment success" webhooks. We test your server to make sure it rejects bad signatures. We also capture a real $1 success message and send it 100 times to see if your server blocks duplicate messages.
Merchant isolation and BOLA
We test for BOLA (Broken Object Level Authorization). We make sure Merchant A cannot see Merchant B's sales data. We ensure Merchant A cannot change Merchant B's payout bank account.
Settlement manipulation
We attack the settlement rules. We try to inject negative numbers into the refund API. We try to break the currency exchange rates to steal micro-cents on every transaction.
Checkout tampering
We test your public payment page. We try to lower the price before we pay. We try to bypass the final OTP verification step by dropping packets.
Third-party vendor risk and integration boundaries
Many startups use Stripe, Flutterwave, or Paystack. They think: "Stripe is secure, so we are secure." This is dangerous.
Stripe is very secure. But how your app talks to Stripe is usually very weak. We call this the integration boundary. Hackers attack the boundary. They attack the API keys you left in your frontend code. They attack the callback URL you forgot to protect. We test the boundary to keep you safe.
Post-breach incident response testing
What happens if a hacker finds a zero-day bug and attacks you at 2:00 AM? Will your team even notice?
During our penetration test, we check your logs. We trigger massive, noisy attacks. We see if your monitoring systems catch us. If they do not, we help you build better alerts. You must detect an attack while it is happening, not three days later when the money is gone.
What we check in a penetration test
- Admin roles: We test refunds, disputes, and settings to stop insider threats.
- APIs and webhooks: We test signatures, rate limits, and trust rules.
- Checkout flow: We test the price, currency, and capture state.
- Actionable reports: We give you clear code snippets to fix every single bug.
Webhook replay attack
A client had great webhook signatures but zero replay protection. We captured a valid $1 webhook message. We sent it 100 times in five seconds. The server gave us $100 in credit. We helped them fix it immediately before they launched.
PCI DSS compliance and premium oversight
Compliance is not enough. PCI DSS rules do not catch deep logic flaws. Our penetration testing finds the real paths hackers use.
But you still need to pass your audits. We provide premium compliance oversight. We map every bug we find to the exact PCI DSS requirement it breaks. We give you a beautiful, auditor-ready report. This proves to your banking partners that your system is truly secure.
Secure your payment gateway with a real penetration test today.
Request a security reviewFrequently asked questions
Does PCI DSS mean we are secure?
No. PCI DSS is just a checklist. It does not test your complex business rules. A hacker can still bypass your webhooks even if you pass PCI DSS. You need real penetration testing to stop real attacks.
How do you test webhooks safely?
We test on a safe staging server first. We send fake webhook signals. We check if your server accepts fake signatures. We do this without breaking real transactions or messing up your live ledger.
What is the most common payment flaw?
BOLA is the most common flaw. One merchant logs in and views another merchant's data. They can even change the payout bank account. We test your app hard to stop this.
Can hackers change the checkout price?
Yes. Hackers change the price in the browser. If your server does not double-check the price, the hacker pays $1 for a $100 item. We test your checkout to prevent this.
Do you test third-party payment providers like Paystack or Stripe?
We do not hack Paystack or Stripe directly. That is illegal. We test how your app connects to them. We test the integration boundaries. That is where 99% of the fatal bugs happen.