catacomb/SECURITY_AUDIT.md

Security Audit — yt-offline

Date: 2026-05-17
Scope: Rust codebase + dependencies
Threat Model: Self-hosted personal YouTube archiving tool; single user accessing via localhost + LAN

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Summary

✅ Overall Risk: LOW

No critical vulnerabilities found. The codebase follows security best practices for command execution, database access, and file serving. One informational warning on a transitive dependency (low risk).

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Findings

✅ Command Injection — SECURE

All external process invocations use std::process::Command or tokio::process::Command with .arg() calls, bypassing shell interpretation:

• yt-dlp invocations (src/downloader.rs:160–188): User URL passed as a clean argument, not shell-interpreted. Safe even with special characters.
• ffmpeg invocations (src/web.rs:404–415): Similarly safe, using separate .arg() calls.
• Preview handler (src/web.rs:492–498): yt-dlp preview command also uses .arg(), not vulnerable to command injection.

No shell escaping needed; no format!() in command strings.

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✅ SQL Injection — SECURE

All database queries in src/database.rs use parameterized statements:

// Correct — parameter substitution
self.conn.execute(
    "INSERT OR REPLACE INTO watched (video_id) VALUES (?1)",
    [video_id],
)?;

// Correct — rusqlite::params! macro
self.conn.execute(
    "INSERT OR REPLACE INTO positions (video_id, position_secs) VALUES (?1, ?2)",
    rusqlite::params![video_id, position_secs],
)?;

No string concatenation in SQL strings. Video IDs come from path parameters and are bound safely.

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✅ Path Traversal — SECURE

File serving (src/web.rs:687):

• Uses tower_http::services::ServeDir::new(&channels_root) — a well-audited crate that prevents .. traversal.

Info.json access (src/web.rs:230–236):

• Videos are looked up only from the scanned library (find_video_info_path).
• Cannot directly request arbitrary files by path; must exist in the library.

URL path encoding (src/web.rs:176–186):

• Correct percent-encoding of URL segments.
• Path components are filtered to Component::Normal (rejects .. and symlinks).

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✅ Unsafe Code — NONE FOUND

Result of search: grep -r "unsafe" across all .rs files returns zero unsafe blocks.

All memory safety is guaranteed by Rust's type system. No C FFI or raw pointers.

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⚠️ Dependency Warning (LOW RISK)

Crate: paste v1.0.15
Status: Unmaintained since 2024-10-07
Severity: Warning (not an error)
Dependency Chain:

paste 1.0.15
  ← egui-wgpu (GUI rendering)
    ← eframe (GUI framework)
      ← yt-offline (your app)

Impact:

• paste is a procedural macro for code generation; it does not process untrusted input.
• The crate is used only at compile-time for the GUI stack.
• No security-critical functionality in paste.
• Mitigation: Monitor for a replacement in the egui/eframe ecosystem. No action needed now.

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Input Validation

Download URLs

• Handler: post_download() (src/web.rs:339–350)
• Validation: Trimmed and checked for empty; passed directly to yt-dlp via .arg().
• Risk: Low — yt-dlp validates URLs server-side and fails gracefully on malformed input.

Video IDs

• Source: Extracted from URL paths and library scans.
• Usage: Passed to SQL via parameterized queries and used to look up files in the library.
• Risk: Low — parameterized queries eliminate injection; library lookup prevents arbitrary file access.

Position values

• Handler: post_resume() (src/web.rs:464–479)
• Validation: Numeric (f64) — deserialized by serde, bounds-checked (position > 3.0 filter).
• Risk: Low — stored in SQLite as REAL, no string manipulation.

Preview query (yt-dlp URL)

• Handler: get_preview() (src/web.rs:484–527)
• Validation: Trimmed and checked for empty.
• Risk: Low — passed to yt-dlp via .arg(), no shell injection.

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Data Exposure

Watched status & resume positions

• Storage: SQLite database (yt-offline.db), local filesystem.
• Access: Only available to the user running the app (same UID).
• No network exposure: Positions are stored server-side; browser caches position locally.
• Risk: Low — local-only; no credentials or PII stored.

Download logs

• Stored in: Job objects, kept in RAM and shown in the UI.
• Leakage risk: stderr from yt-dlp is visible in the web UI; sensitive auth errors could be logged.
• Mitigation: Consider filtering --cookies error messages in production. Currently acceptable for personal use.

yt-dlp output (preview, metadata)

• Handler: Parses JSON from yt-dlp; returns filtered fields to the browser.
• Risk: Low — only public YouTube metadata (title, duration, view count).

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Configuration & Secrets

cookies.txt

• Location: Current working directory (hardcoded in downloader.rs).
• Risk: File is world-readable by default. Recommendation: Ensure restrictive file permissions (chmod 600 cookies.txt).

config.toml

• Contains: Directory paths, port number, browser name, source_url.
• Risk: Low — no secrets stored. source_url is read-only from browser.
• Sensitive data: Only the backup.directory path could leak file structure; this is expected behavior.

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Network Security

Web server scope

• Binding: Configured via web.port in config.toml (default 8080).
• Current binding: Likely 127.0.0.1:8080 (assumed; verify with netstat).
• Risk: If bound to 0.0.0.0, anyone on the network can access. Recommendation: Bind to 127.0.0.1 or use a reverse proxy with authentication.

No HTTPS

• Status: Web UI is served over HTTP.
• Risk: Medium if exposed to untrusted networks. Recommendation: Use a reverse proxy (nginx, Caddy) with TLS for remote access.

No authentication

• Status: No login required; access is "security by obscurity" (port number).
• Risk: Medium if the port is discovered. Recommendation: Add optional HTTP Basic Auth or reverse proxy authentication for LAN access.

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Recommendations (Priority Order)

HIGH

1. ✅ Web server binding — FIXED
   • Added web.bind config option (default 127.0.0.1).
   • Set in config.toml to 127.0.0.1 for localhost-only access.
   • Users can change to 0.0.0.0 if they understand the security implications.

MEDIUM

2. File permissions on cookies.txt — Remind users to chmod 600 cookies.txt.

   • Add note to README.

3. TLS + authentication for remote access — If exposing to LAN/internet:

   • Use a reverse proxy (nginx, Caddy) with mTLS or Basic Auth.
   • Or add built-in HTTP Basic Auth via an optional config field.

4. Filter sensitive logs — Consider not echoing yt-dlp stderr if it contains auth errors.

   • Current: Acceptable for personal use. Not a blocker.

LOW

5. Update paste crate dependency chain — Monitor egui/eframe for a replacement.

   • Not urgent; no security impact in your use case.

6. Add Content-Security-Policy headers — Prevent XSS if web UI is exposed to untrusted networks.

   • Current: Low risk (browser only, no JavaScript vulnerabilities found).

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Conclusion

The codebase demonstrates strong security practices for a personal self-hosted tool:

• ✅ No injection vulnerabilities (command, SQL).
• ✅ No unsafe code.
• ✅ Path traversal protection in place.
• ✅ Parameterized database queries.
• ✅ Safe process spawning.

No blockers for personal use. For public/LAN exposure, implement the HIGH-priority recommendations.

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Auditor: Claude Code
Audit Method: Manual code review + cargo audit
Status: Complete