Wuppertal police have warned of a QR code scam targeting sellers on online classified ad platforms. Three cases were documented in the Märkischer Kreis district in the first half of 2025, according to police.
QR Codes Instead of Bank Transfers
Three fraud cases were reported in Iserlohn, Meinerzhagen, and Altena (Märkischer Kreis) in the first half of 2025, police said. The victims were sellers on classified ad portals.
According to police, a supposed buyer responds to an ad – for items such as a camera, shoes, or a Lego set. Instead of a bank transfer, the buyer sends a QR code, claiming it is the fastest way to complete the payment.
The documented cases
- •Iserlohn (January 2025): A camera seller scanned a QR code he had received and was directed to a fake payment page.
- •Meinerzhagen (February 2025): A shoe seller received a code via WhatsApp and entered bank details.
- •Altena (March 2025): A Lego seller was prompted to enter login credentials via a manipulated code.
How the Scam Works
Step 1: Initial Contact
The scammer responds to a classified ad posing as a genuine buyer, police said. Communication often takes place via WhatsApp or email.
Step 2: QR Code Instead of Transfer
Instead of a bank transfer, the scammer sends a QR code, claiming it will confirm the payment or speed up the transfer, according to police.
Step 3: Fake Payment Page
The QR code leads to a replica website of a well-known payment provider such as PayPal or Klarna. Logo, colors, and layout resemble the original.
Step 4: Data Theft
Victims are asked to enter bank details or login information for supposed verification. Once entered, the data gives the scammers access to the account.
Step 5: Unauthorized Debit
Instead of receiving money, the seller's account is debited. Several transactions are often carried out before the victim notices the fraud.
Why the Scam Works
Trust in the Sales Process
Sellers expect to receive money, not to pay. The prospect of a quick payment lowers vigilance.
Replica Payment Sites
The fake payment pages are difficult to distinguish from real websites. The URL also appears legitimate at first glance, for example 'paypa1-secure.com' instead of 'paypal.com'.
Time Pressure and Manipulation
Scammers put sellers under time pressure with statements such as 'I need the item urgently', according to police.
Communication Outside the Platform
Once communication moves from the classified ad platform to WhatsApp or email, the platform's security mechanisms no longer apply.
Police Recommendations
Wuppertal police advise sellers on online platforms to take the following precautions:
1. Stay on the Platform
Conduct all sales negotiations within the classified ad platform. Do not switch to WhatsApp, email, or other channels.
2. No QR Codes for Payments
Legitimate buyers pay by bank transfer or use the platform's payment function. QR codes are not customary for payment recipients.
3. Check Internet Addresses
After scanning a QR code, check the target page's URL. Look for typos, additional characters, or unusual domains.
4. Never Enter Login Credentials
Sellers do not need to log in or verify anything to receive money. Anyone asking for login details is attempting fraud, police said.
5. Be Wary of Time Pressure
Scammers press for haste. Legitimate buyers are willing to wait for a regular bank transfer.
QRTrust: Checking QR Codes Before Opening
QRTrust checks the target URL of a QR code before the page is opened. The service compares addresses in real time against databases of known phishing sites – whether the code comes from a classified ad, a parking meter, or a letter.
Main functions
- Scan QR codes in the browser instead of the camera app
- Check against 50,000+ known phishing URLs
- AI-based detection of suspicious patterns, such as typos in domain names
- Redirect tracking: redirects are resolved and the final target URL is shown
- Warning before the site is visited
How to use it
- Open qrtrust.de in browser (works on any smartphone)
- Tap "Scan QR Code"
- Point camera at the code
- Wait for result: Green (safe), Yellow (suspicious), Red (danger)
- Only proceed with green result
Integration for Classified Ad Platforms
Platforms such as eBay Kleinanzeigen, Vinted, or Kleinanzeigen.de can integrate QRTrust via interfaces:
API Integration
QRTrust provides a REST API that can be integrated into existing security systems. Suspicious QR codes can be blocked automatically.
Browser Extension
A browser extension automatically checks QR codes on websites.
Whitelisting
Platforms can have their official QR codes, for example for payments, registered as safe.
Advice for Those Affected
Police advise those who have scanned a suspicious QR code and entered data to take the following steps:
1. Contact Your Bank
Contact your bank and have your card blocked. If you act quickly, transactions can often still be stopped.
2. Change Passwords
Change all passwords you entered on the fake site, especially for online banking and email.
3. Notify Police
File a report with your local police or online via the online police station in NRW. Preserve evidence such as screenshots, chat logs, and phone numbers.
4. Report to the Platform
Report the fraud to the classified ad platform. It can block the scammer's account and warn other users.
5. Report the Phishing URL
Report the fake website to Google Safe Browsing so it can be added to warning lists.
QR Code Fraud Reaches Online Marketplaces
The cases from Märkischer Kreis show that quishing is no longer limited to parking meters and official mail. Scammers are increasingly exploiting situations in which people scan QR codes – now also in online sales.
Police advise sellers to stay on the platform, refuse QR codes for payments, and be wary of time pressure.
Checking a QR code's target address before opening it can help detect fraud attempts before damage occurs.
About QRTrust
QRTrust is Germany's first QR code security platform, developed in Dortmund. AI-powered real-time detection, a local threat database and multi-layered security checks protect citizens, authorities and businesses from quishing attacks. GDPR compliant, hosted in Germany.