Ecommerce Systempay 1.0 Critical Weak Crypto Vulnerability (CVE-2020-37168)
A critical vulnerability, CVE-2020-37168, has been identified in Ecommerce Systempay 1.0, stemming from a weak cryptographic implementation. According to the National Vulnerability Database, this flaw allows attackers to brute force the 16-character production secret key used for payment signature generation. This isn’t theoretical; the impact is direct and severe.
Attackers can intercept payment form data and signatures from POST requests, then use SHA1 hash comparison to iteratively test key candidates. Once the correct production key is discovered, they can forge valid payment signatures, enabling the manipulation of transaction amounts. The National Vulnerability Database assigns this a CVSS score of 9.8 (CRITICAL), highlighting the ease of exploitation (network-adjacent, low complexity, no privileges or user interaction required) and the complete compromise of confidentiality, integrity, and availability.
This isn’t just about data theft; it’s about financial fraud at scale. The attacker’s calculus here is simple: weak crypto means easy money. Defenders using this system must understand that payment integrity is entirely compromised. This isn’t a partial bypass; it’s a full-on key recovery and forging capability.
What This Means For You
- If your organization uses Ecommerce Systempay 1.0, you are exposed to critical financial fraud and data manipulation. This isn't a patch-and-forget; you need to immediately assess your payment infrastructure, assume the production secret key is compromised, and implement stronger cryptographic controls for payment signature generation. Audit all past transactions for anomalies and assume any payment using this system could have been tampered with.
Related ATT&CK Techniques
🛡️ Detection Rules
3 rules · 6 SIEM formats3 detection rules auto-generated for this incident, mapped to MITRE ATT&CK. Sigma YAML is free — export to any SIEM format via the Intel Bot.
CVE-2020-37168 - Systempay Weak Crypto - Brute Force Key Search
title: CVE-2020-37168 - Systempay Weak Crypto - Brute Force Key Search
id: scw-2026-05-13-ai-1
status: experimental
level: critical
description: |
Detects POST requests to a '/payment' endpoint containing a 'signature=' parameter, indicative of the brute-force key search attack described in CVE-2020-37168. Attackers extract payment form data and signatures to iteratively test key candidates using SHA1 hash comparison.
author: SCW Feed Engine (AI-generated)
date: 2026-05-13
references:
- https://shimiscyberworld.com/posts/nvd-CVE-2020-37168/
tags:
- attack.initial_access
- attack.t1190
logsource:
category: webserver
detection:
selection:
cs-method:
- 'POST'
cs-uri:
- '/payment'
selection_indicators:
cs-uri-query|contains:
- 'signature='
condition: selection AND selection_indicators
falsepositives:
- Legitimate administrative activity
Source: Shimi's Cyber World · License & reuse
Indicators of Compromise
| ID | Type | Indicator |
|---|---|---|
| CVE-2020-37168 | Cryptographic Failure | Ecommerce Systempay 1.0 |
| CVE-2020-37168 | Cryptographic Failure | Weak cryptographic implementation for 16-character production secret key |
| CVE-2020-37168 | Cryptographic Failure | Brute force attack on payment signature generation key |
| CVE-2020-37168 | Cryptographic Failure | SHA1 hash comparison for key discovery |
| CVE-2020-37168 | Cryptographic Failure | Forging valid payment signatures and manipulating transaction amounts |
Written by SCW Vulnerability Desk
Source & Attribution
| Source Platform | NVD |
| Channel | National Vulnerability Database |
| Published | May 13, 2026 at 19:16 UTC |
This content was AI-rewritten and enriched by Shimi's Cyber World based on the original source. All intellectual property rights remain with the original author.
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