/param-discover

description: Discover hidden HTTP parameters on a URL or list of URLs using Arjun (or x8 fallback). Hidden params are gold for IDOR, SSRF, LFI, redirect, and authorization bypass — often missed by automated scanners. Usage: /param-discover <url> | /param-discover -l <urls-file>

/param-discover

Find HTTP parameters the application accepts but doesn't link from any visible endpoint. Useful when an endpoint looks unreachable or returns a generic response — often a hidden `id`, `user`, `redirect`, `file`, or `debug` param unlocks the real surface.

Usage

/param-discover https://api.target.com/v2/user
/param-discover -l recon/target.com/live/urls.txt

Tools

`tools/param_discovery.sh` prefers `arjun` (richer JSON output, ML-driven diffing) and falls back to `x8` (Rust, faster on huge wordlists). Install hint:

pipx install arjun
# or
cargo install x8

Why it pays

• Hidden `redirect=` / `next=` → open redirect, SSRF, OAuth code theft chain.
• Hidden `id=` / `user_id=` → IDOR.
• Hidden `file=` / `path=` / `template=` → LFI, SSTI, RFI.
• Hidden `debug=` / `admin=` → privilege escalation toggles.
• Hidden `callback=` / `jsonp=` → reflected XSS via JSONP.

After discovery, feed the URL+param into `/hunt --vuln-class <best-fit>` for targeted testing.

Output

`findings/params/<timestamp>/`:

• `arjun.json` / `arjun_summary.txt` — endpoint → discovered params
• `x8.txt` — diff-based hits when arjun is unavailable