Attack Chain

1. An attacker crafts a malicious mathematical expression designed to exploit the vulnerability in math.js.
2. The attacker submits the malicious expression to a vulnerable application that uses math.js for expression parsing.
3. The application’s server-side code receives the input and passes it to the math.js evaluate() function.
4. The vulnerable evaluate() function processes the expression, leading to unintended modification of object attributes.
5. This modification triggers the execution of arbitrary JavaScript code embedded within the malicious expression.
6. The attacker’s JavaScript code executes within the context of the server-side application, bypassing security controls.
7. The attacker gains unauthorized access to sensitive data, modifies system configurations, or installs malicious software.
8. The attacker achieves full remote code execution (RCE), compromising the entire application.

Impact

Successful exploitation of this vulnerability allows attackers to execute arbitrary JavaScript code on the server running the vulnerable application. This can result in complete system compromise, including unauthorized data access, data modification, and denial of service. If the compromised application has access to sensitive databases or internal systems, the attacker can pivot to further compromise the internal network. The vulnerability impacts any application using math.js < 15.2.0 and allows users to evaluate arbitrary expressions, with potentially widespread consequences depending on the application’s role and permissions.

Recommendation

• Immediately upgrade math.js to version 15.2.0 or later to patch the vulnerability (GHSA-jvff-x2qm-6286).
• If immediate patching is not possible, consider disabling or restricting user-provided expression evaluation functionalities.
• Deploy the Sigma rules below to your SIEM to detect potential exploitation attempts against vulnerable math.js instances.
• Monitor web server logs for suspicious patterns in user input indicative of expression injection attacks.
• Implement input validation and sanitization measures to prevent malicious expressions from reaching the math.js parser.