## 2024-05-24 - SSRF in WebDAV connection test
**Vulnerability:** The `_test_webdav_connection` function had a custom SSRF check that failed to resolve DNS names, allowing attackers to bypass the check by providing a domain that resolves to an internal IP (e.g., `127.0.0.1`).
**Learning:** DNS resolution is required for robust SSRF protection when validating URLs provided by users.
**Prevention:** Use a centralized `is_private_ip` function (now in `app/utils/network.py`) that resolves the hostname to its IPs and checks if any are private.
## 2026-03-22 - B310: urllib.request.urlopen replaced with httpx
**Vulnerability:** The `_test_webdav_connection` function used `urllib.request.urlopen`, which natively supports dangerous schemes like `file://` or `ftp://` and follows redirects by default, potentially allowing SSRF bypasses or Local File Inclusion.
**Learning:** `urllib.request` should be avoided for user-supplied URLs. Even when URL schemes are manually validated, `urllib`'s default redirect following behavior can bypass SSRF protections (e.g. redirecting to `127.0.0.1`).
**Prevention:** Use a modern, safer HTTP client like `httpx` with `follow_redirects=False` when testing user-provided URLs.