To automatically scan your client-side code for common vulnerabilities, you can use the Salesforce Code Analyzer. This tool supports multiple engines, such as ESLint, PMD, RetireJS, and Salesforce Graph Engine, to identify vulnerabilities in JavaScript, Lightning, TypeScript, and Visualforce code.
You can install the Code Analyzer as a Salesforce CLI plugin, run scans during your development lifecycle, and address flagged issues. For ongoing monitoring, you can also integrate the tool into a continuous integration (CI) process. Additionally, for external endpoints, consider using Dynamic Application Security Test (DAST) scanners like ZAP or Burp Suite.