Third-Party Script Vuln: SRI & CSP Hardening Guide

Vulnerability Overview Vulnerability Name: Third-Party Script Security Vulnerability Risk Level: High Scope of Impact: - All third-party JavaScript scripts included via tags - Includes payment gateways, analytics tools, ad networks, chat widgets, etc. - Any script that is unverified or of unknown origin may serve as an attack vector Core Risks: - Scripts can execute arbitrary code; if tampered or vulnerable, attackers can leverage them to run malicious code - Common attack vectors: XSS, supply chain attacks, script hijacking - Third-party scripts are usually not directly controlled by the website owner but execute under the site's own domain, inheriting equivalent privileges Key Issues and Mitigations What qualifies as a "third-party script"? - JS files not written or maintained by the website owner - Scripts loaded from external domains via - Includes CDN-hosted scripts, SaaS service embedded scripts, etc. Who is responsible for third-party script security? - The website owner bears ultimate responsibility (even if the script comes from a third party) - Must establish a script inventory, perform regular audits, and enable SRI (Subresource Integrity) - Third-party vendors should provide security updates and a vulnerability disclosure mechanism How to reduce the risk? - Establish a script inventory - Use SRI checksums (SHA-384/SHA-512) - Enable CSP (Content Security Policy) to restrict script sources - Enable or for critical scripts - Perform periodic scans and monitor for changes in script behavior Remediation Steps 1. Enable SRI (Subresource Integrity) - Add the attribute to the tag, specifying the script's hash value - Example: 2. Implement CSP (Content Security Policy) - Restrict script sources via HTTP headers or tags - Example: 3. Minimize the number and sources of scripts - Remove unnecessary third-party scripts - Prioritize vendors that support SRI and CSP - Use or for critical scripts to avoid blocking rendering 4. Monitoring and Auditing - Use tools (such as SRI Generator, CSP Evaluator) to generate checksums - Periodically review the script inventory and remove scripts that are outdated or of unknown origin - Set up alerting mechanisms to block loading when the script hash does not match POC / Exploit Code Example > Note: SRI hash values must be calculated based on the actual script content. If a script is updated but the hash is not synchronized, the page will refuse to load that script.

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Third-Party Script Vuln: SRI & CSP Hardening Guide