bypass-403

A command that tests an HTTP endpoint returning 401 or 403, which mean access is denied, using alternate headers, paths, methods, and request formats. It also checks for common web-firewall products.

In plain words
What is it for?
Use it during authorized security testing of a target URL or a saved list of blocked responses to probe documented bypass patterns.
Why use it?
It helps determine whether an access block is caused by a routing rule, firewall, or request-handling difference.

Command

Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

agentmods
npx agentmods add commands/awarexone/agentic-bug-hunter/bypass-403
Clone the repo
git clone --depth 1 https://github.com/Awarexone/Agentic-Bug-Hunter
Per session 0 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 1,470 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 1 finding. Scan, not verified.
Origin original No closer match found in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5 $0.00000 $0.01470
Opus 5 $0.00000 $0.00735
Sonnet 5 $0.00000 $0.00294
Haiku 4.5 $0.00000 $0.00147

Measured yesterday against content hash c7c2ff93fc46, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

bypass-403 scanned grade A with 1 finding against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured yesterday.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Makes network callslowCapability

Not a fault in itself. Listed so you know the mod talks to something, and to what.

built-in fallback runs the same set with `curl`.
commands/bypass-403.md · 108 lines

How it starts

The opening of the file, as written. The whole thing — 108 lines — stays where its author put it; the contents beside it link to each section on GitHub.

/bypass-403

Try to bypass an HTTP 403/401 response with header injection, path encoding, and method tampering — the standard battery from disclosed reports.

Usage

/bypass-403 https://target.com/admin
/bypass-403 -l recon/target.com/live/status_403.txt

What it tries

Class Examples
IP spoofing headers X-Forwarded-For: 127.0.0.1, True-Client-IP, CF-Connecting-IP, X-Originating-IP, X-ProxyUser-Ip, Client-IP, Forwarded, X-Remote-Addr, X-Remote-IP, Via, X-HTTP-Method-Override
Path tricks /%2e/, /%252e/, /.xxx, /xxx/, /xxx;/, /xxx..;/, /xxx%20, /xxx%09, //xxx, /./xxx
Suffix tricks /xxx.json, /xxx.html, /xxx.css, /xxx#
Method tampering POST, PUT, PATCH, TRACE on a GET-only endpoint
Content-Type confusion application/json POST, multipart/form-data POST, dual Content-Type header trick
Vendor-specific Cloudflare (TE + X-Forwarded-Host), AWS WAF (/**/ comment split), Imperva (%c0%2e unicode), F5 (double-slash path)
WAF fingerprint Auto-detect via response headers/cookies (cf-ray → Cloudflare, x-amzn → AWS, TS cookie → F5, incap_ses → Imperva)

When byp4xx (lobuhi/byp4xx) is installed it is used directly; otherwise the built-in fallback runs the same set with curl.

WAF Fingerprinting

The script auto-detects WAF vendor from response headers and cookies, then applies vendor-specific tricks automatically. Uses wafw00f when installed; falls back to header/cookie signature match.

Fingerprint saved to findings/bypass/<ts>/waf_fingerprint.txt.

Payload Encoding (separate tool)

For payload-level bypass (SQLi/XSS keyword blocked by WAF):

tools/waf_encoder.py "' OR 1=1--" --class sqli
tools/waf_encoder.py "<script>alert(1)</script>" --class xss
tools/waf_encoder.py "<payload>" --layers 3   # triple URL-encode
tools/waf_encoder.py "<payload>" --json       # machine-readable output

Generates 20-40 variants: URL encoding (1-3 layers), unicode escape, HTML entity, SQL comment injection, MySQL version comment, case mixing, operator substitution, base64 XSS wrappers, null byte insertion.

Read the full file on GitHub · 108 lines

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. yesterday First seen · 108 lines · 0 tokens per session scan A c7c2ff93fc46

Subscribe to this mod's changes

bypass-403 is a command published in the GitHub repository Awarexone/Agentic-Bug-Hunter (4,651 stars, last pushed today), licensed MIT. It costs nothing until one of its globs matches a file; then it loads 1,470 tokens. A static security scan graded it A with 1 finding (makes network calls). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.

Related

Other commands, from other repositories

recon

Run full recon pipeline on a target — subdomain enum (Chaos API + subfinder), live host discovery (dnsx + httpx), URL crawl (katana + waybackurls + gau), gf pattern classification, nuclei scan. Outputs to recon/ / directory. Usage: /recon target.com.

elementalsouls/Claude-BugHunter · 65 tokens

hunt

Active vulnerability hunting. Two-track dispatcher — asks Red Team vs WAPT, hands off to hunt-dispatch skill and sibling commands. Usage: /hunt target.com | /hunt .target.com | /hunt targets.txt [--vuln-class X] [--source-code P] [--chrome].

elementalsouls/Claude-BugHunter · 63 tokens

token-scan

Meme coin and token security scan — checks for rug pull vectors (hidden mint, honeypot, fee manipulation, LP lock bypass, authority retention, bonding curve exploits, fake renounce, sandwich amplification). Manual 8-class grep audit (with an optional automated scanner if present). Usage: /token-scan [--chain solana].

elementalsouls/Claude-BugHunter · 79 tokens

autopilot

Run autonomous hunt loop on a target — scope check → recon → rank surface → hunt → validate → report with configurable checkpoints. Usage: /autopilot target.com [--paranoid|--normal|--yolo].

elementalsouls/Claude-BugHunter · 49 tokens

validate

Validate a finding — runs 7-Question Gate + 4-gate checklist. Kills weak findings before report writing. Prevents N/A submissions that hurt validity ratio. Usage: /validate.

elementalsouls/Claude-BugHunter · 41 tokens

triage

Quick 7-Question Gate triage on a finding before writing a report. Kills N/A submissions before they happen. Faster than /validate — for quick go/no-go decisions. Usage: /triage.

elementalsouls/Claude-BugHunter · 45 tokens