CVE-2023-23941
📋 TL;DR
This CVE describes an integrity vulnerability in SwagPayPal's JavaScript-based PayPal checkout methods where the payment amount and item list sent to PayPal may not match the actual order created in Shopware. This could allow attackers to manipulate payment amounts or items during checkout. Affected users are Shopware e-commerce sites using SwagPayPal with PayPal Plus, Smart Payment Buttons, SEPA, Pay Later, Venmo, or Credit Card payment methods.
💻 Affected Systems
- SwagPayPal (Shopware PayPal integration)
📦 What is this software?
Swagpaypal by Shopware
⚠️ Risk & Real-World Impact
Worst Case
Attackers could pay significantly less than the actual order total or receive items they didn't pay for, leading to financial loss for merchants and potential inventory discrepancies.
Likely Case
Minor payment discrepancies where attackers exploit the mismatch to pay slightly less than the actual order amount.
If Mitigated
No impact if proper controls like payment verification and order reconciliation are implemented.
🎯 Exploit Status
Exploitation requires user interaction during checkout but no authentication to the Shopware backend.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 5.4.4
Vendor Advisory: https://github.com/shopware/SwagPayPal/security/advisories/GHSA-vxpm-8hcp-qh27
Restart Required: No
Instructions:
1. Update SwagPayPal to version 5.4.4 or later via Shopware's extension manager or Composer. 2. Clear Shopware cache. 3. Test PayPal checkout functionality.
🔧 Temporary Workarounds
Disable vulnerable payment methods
allTemporarily disable the affected JavaScript-based PayPal payment methods in Shopware admin.
Install Security Plugin
allInstall and enable Shopware Security Plugin version 1.0.21 or later.
🧯 If You Can't Patch
- Disable all JavaScript-based PayPal payment methods immediately.
- Implement manual order verification and reconciliation processes for PayPal transactions.
🔍 How to Verify
Check if Vulnerable:
Check SwagPayPal version in Shopware admin under Extensions > My extensions, or run: composer show shopware/swag-paypalCheck Version:
composer show shopware/swag-paypal | grep versionsVerify Fix Applied:
Confirm SwagPayPal version is 5.4.4 or later and test PayPal checkout with order amount validation.📡 Detection & Monitoring
Log Indicators:
- Discrepancies between PayPal transaction amounts and Shopware order amounts in payment logs.
- Multiple failed payment validations for PayPal transactions.
Network Indicators:
- Unusual patterns in PayPal API call amounts versus order values.
SIEM Query:
source="shopware_logs" AND ("PayPal" AND "amount mismatch" OR "validation failed")🔗 References
- https://github.com/shopware/SwagPayPal/commit/57db5f4a57ef0a1646b509b415de9f03bf441b08
- https://github.com/shopware/SwagPayPal/security/advisories/GHSA-vxpm-8hcp-qh27
- https://github.com/shopware/SwagPayPal/commit/57db5f4a57ef0a1646b509b415de9f03bf441b08
- https://github.com/shopware/SwagPayPal/security/advisories/GHSA-vxpm-8hcp-qh27
