# Sentinel's Journal

## 2026-02-07 - Telegram Bot Authorization Bypass
**Vulnerability:** The Telegram Deployment Bot (`scripts/telegram_deploy_bot.py`) contained a "Fail Open" vulnerability where omitting the `TELEGRAM_ALLOWED_USER_IDS` environment variable resulted in granting access to *all* Telegram users instead of *none*.
**Learning:** Security controls must default to deny (Fail Closed). Implicitly allowing access when configuration is missing creates silent vulnerabilities that are hard to detect until exploited.
**Prevention:** Ensure all authorization checks explicitly return `False` or throw an exception if the access control list is empty or undefined. Never default to `True` in security-critical paths.

## 2026-02-13 - [Documentation] Cloudflare Nameservers and Domain Unification
- Updated Cloudflare nameservers to daisy.ns.cloudflare.com and rocco.ns.cloudflare.com.
- Unified domain name to lengkundee01.org across CNAME and PWA documentation.

## 2026-02-23 - Web Dashboard Error Leakage
**Vulnerability:** The web dashboard (`scripts/web_dashboard.py`) was catching all exceptions and returning the raw exception message to the user, potentially leaking sensitive internal state or file paths.
**Learning:** Developers often prioritize debugging convenience over security by returning raw errors, which is dangerous in production.
**Prevention:** Always catch exceptions in web handlers, log the full details server-side (e.g., to stderr), and return a generic "Internal Server Error" message to the client.