FSV — web security scanner & MCP server

For the problems nobody is watching: dangling DNS and subdomain takeover, orphaned cloud buckets, scripts from compromised or expired CDN domains, SPF includes that no longer exist, debug mode left on in production, secrets in your JavaScript, end-of-life software — and the attack paths that turn small findings into a real compromise, each with the cheapest fix that breaks it.

Runs as a CLI, a dashboard, an MCP server for AI assistants (Claude, Cursor, VS Code), and a CI step. Detection only: it never exploits, never claims a resource, never tests a credential.

Authorized use only. Scan only systems you own or are explicitly authorized in writing to test.

Install

pip install fsv            # Python 3.11+
fsv doctor                 # checks dependencies, DNS, database

Scan

fsv scan example.com --authorize                     # full scan of a site you own
fsv scan example.com --authorize --profile passive   # read-only: no payloads sent
fsv fixes <scan_id> nginx                            # paste-ready config for what was found
fsv web                                              # dashboard → http://127.0.0.1:7474

Connect your AI assistant

fsv mcp-config --client claude-code      # prints:  claude mcp add fsv -- /path/to/fsv-mcp
fsv mcp-config --client claude-desktop   # or: cursor · vscode

Then ask: “Use the security_review prompt on https://my-site.example — I own it.” The assistant confirms authorization, runs a passive check and a full scan, leads with attack paths and hands you the fixes.

What it finds

32 modules — DNS takeover, cloud storage, script supply chain, SPF/DMARC/DKIM, JavaScript secrets and source maps, vulnerable and end-of-life libraries, ~100 content-validated exposure checks, framework debug pages, headers/CSP/cookies, and benign active checks for common reflected issues. Findings carry severity, confidence, CWE, OWASP Top 10 category and remediation; reports in Markdown, JSON, HTML, SARIF and CSV.

Links

• Source, full documentation and screenshots: https://github.com/twayst0/fsv
• Changelog: https://github.com/twayst0/fsv/blob/main/CHANGELOG.md
• Security policy: https://github.com/twayst0/fsv/blob/main/SECURITY.md
• Contact: statways1707@gmail.com · Discord .tways

License: FSV Personal Use License — free for personal, educational and non-commercial security research. Commercial use is prohibited (see LICENSE); licensing questions: statways1707@gmail.com.