{"description":"Trending threats, MITRE ATT\u0026CK coverage, and detection metadata. Fed continuously.","feed_url":"https://feed.craftedsignal.io/products/systempay-1.0/feed.json","home_page_url":"https://feed.craftedsignal.io/","items":[{"_cs_actors":[],"_cs_cpes":[],"_cs_cves":[{"cvss":9.8,"id":"CVE-2020-37168"}],"_cs_exploited":false,"_cs_has_poc":false,"_cs_poc_references":[],"_cs_products":["Systempay 1.0"],"_cs_severities":["critical"],"_cs_tags":["cve","credential-access","ecommerce","payment-fraud"],"_cs_type":"advisory","_cs_vendors":[],"content_html":"\u003cp\u003eSystempay 1.0 suffers from a critical vulnerability, CVE-2020-37168, stemming from a weak cryptographic implementation in its payment signature generation. Attackers exploit this flaw by targeting the 16-character production secret key. This allows an attacker to forge valid payment signatures, potentially leading to unauthorized transaction amount modifications. This is particularly concerning for e-commerce platforms relying on Systempay 1.0 for payment processing, as it directly jeopardizes the integrity of financial transactions. Successful exploitation could result in significant financial losses and reputational damage. The vulnerability impacts all installations of Systempay version 1.0.\u003c/p\u003e\n\u003ch2 id=\"attack-chain\"\u003eAttack Chain\u003c/h2\u003e\n\u003col\u003e\n\u003cli\u003eAttacker intercepts a legitimate payment request sent to the Systempay payment endpoint. This request includes the payment form data and the associated payment signature.\u003c/li\u003e\n\u003cli\u003eThe attacker extracts the payment form data and the corresponding signature from the intercepted POST request.\u003c/li\u003e\n\u003cli\u003eAttacker begins a brute-force attack to guess the 16-character production secret key used for payment signature generation.\u003c/li\u003e\n\u003cli\u003eThe attacker generates a candidate signature using the extracted payment form data and a guessed secret key. The attacker will then hash the result using SHA1.\u003c/li\u003e\n\u003cli\u003eThe attacker compares the generated signature with the original signature.\u003c/li\u003e\n\u003cli\u003eIf the generated signature matches the original signature, the attacker has successfully identified the correct production secret key.\u003c/li\u003e\n\u003cli\u003eUsing the discovered secret key, the attacker modifies the payment form data (e.g., transaction amount) to their advantage.\u003c/li\u003e\n\u003cli\u003eThe attacker generates a new, valid payment signature for the modified payment form data using the discovered secret key. The attacker then submits the forged payment request.\u003c/li\u003e\n\u003c/ol\u003e\n\u003ch2 id=\"impact\"\u003eImpact\u003c/h2\u003e\n\u003cp\u003eSuccessful exploitation of CVE-2020-37168 allows attackers to forge valid payment signatures, enabling them to manipulate transaction amounts. This could lead to direct financial losses for merchants and customers. Given the severity (CVSS 9.8), organizations using Systempay 1.0 should consider this a high priority incident.\u003c/p\u003e\n\u003ch2 id=\"recommendation\"\u003eRecommendation\u003c/h2\u003e\n\u003cul\u003e\n\u003cli\u003eExamine web server logs for unusual POST requests to the payment endpoint that may indicate signature brute-forcing (see the rule \u003ccode\u003eDetect Systempay Potential Key Brute-Force\u003c/code\u003e).\u003c/li\u003e\n\u003cli\u003eSince there is no patch available, consider migrating to a different payment processing platform or implementing a robust Web Application Firewall (WAF) with rate limiting to mitigate brute-force attempts.\u003c/li\u003e\n\u003cli\u003eMonitor network traffic for patterns associated with brute-force attempts against payment endpoints (see rule \u003ccode\u003eDetect Systempay Key Forge via Modified Payment\u003c/code\u003e).\u003c/li\u003e\n\u003cli\u003eImplement additional security measures, such as multi-factor authentication, to protect against unauthorized access to payment processing systems.\u003c/li\u003e\n\u003c/ul\u003e\n","date_modified":"2026-05-13T16:17:42Z","date_published":"2026-05-13T16:17:42Z","id":"https://feed.craftedsignal.io/briefs/2026-05-systempay-key-forge/","summary":"Systempay 1.0 contains a weak cryptographic implementation vulnerability (CVE-2020-37168) allowing attackers to brute-force the production secret key, forge payment signatures, and manipulate transaction amounts.","title":"Systempay 1.0 Weak Crypto Allows Payment Signature Forging (CVE-2020-37168)","url":"https://feed.craftedsignal.io/briefs/2026-05-systempay-key-forge/"}],"language":"en","title":"CraftedSignal Threat Feed — Systempay 1.0","version":"https://jsonfeed.org/version/1.1"}