A critical cryptographic weakness in Ecommerce Systempay 1.0 allows attackers to forge payment signatures and manipulate transaction data.

The software employs an insecure cryptographic implementation for its 16-character production secret key. An attacker can perform a brute-force attack on the key using captured POST requests, subsequently allowing for the forging of valid payment signatures.

With a CVSS score of 9.8, this flaw presents a direct financial risk. Attackers can manipulate transaction amounts and payment data, leading to significant financial losses, fraud, and potential regulatory penalties for non-compliance with payment processing standards (e.g., PCI-DSS).

Immediate Action: Upgrade to the latest version of the Ecommerce Systempay software and rotate all secret keys immediately.

Proactive Monitoring: Monitor payment transaction logs for inconsistencies, such as unexpected transaction amounts or signatures that do not match expected patterns.

Compensating Controls: Implement strict rate limiting on the payment endpoint to prevent brute-force attempts on the secret key.

Public Exploit Available: Unknown

Financial integrity is paramount; the ability to forge payment signatures effectively negates the security of the entire payment workflow. Organizations must prioritize upgrading this component and treat all transaction data processed through this version as potentially compromised.