403-bypass SKILL.md skillA
403-bypass from dreadnode/capabilities is an agent skill: a SKILL.md folder an AI agent loads when a task calls for it.
mdr add dreadnode/capabilities/403-bypass@git:20260504.2a64374Pins git:20260504.2a64374 in mdr.lock. Pin the fingerprint instead.
- Audit grade
- A, 17 of 17 checks passed
- Kind
- SKILL.md skill
- Repository
- dreadnode/capabilities
- Path
capabilities/web-security/skills/403-bypass/SKILL.md- Versions recorded
- 1
- Latest version
- git:20260504.2a64374, committed May 4, 2026
- Size
- 9,828 bytes
- Repository stars
- 22
- License
- MIT
Systematic 403/401 bypass via header spoofing, path manipulation, verb tampering, and protocol tricks. Use when endpoint returns 403/401 and you suspect ACL enforcement at proxy/WAF layer rather than application layer.
Collected from public GitHub. Every version is saved exactly as it was and never changes. Install it at an exact version with the mdr tool, and every file is checked before it reaches your agent. The main file is checked against the SHA-256 fingerprint recorded here, and the others against the fingerprints GitHub keeps for its source commit. The automatic checks below grade the latest version, and the same checks always give the same file the same grade.
What the file says
# 403 Bypass ## When to Use - Endpoint returns 403/401 and you suspect the block is at proxy/WAF/CDN, not application code - Admin or internal paths discovered via JS analysis, wordlisting, or sitemap - Different status codes for same resource under different conditions (layered enforcement signal) ## Triage First Before spraying payloads, determine WHERE the 403 originates: 1. **Response body/headers** -- WAF signature (Cloudflare, Akamai, Imperva, custom error page) vs framework error 2. **Timing** -- instant 403 = proxy/WAF rule; delayed 403 = app-level auth check 3. **Consistency** -- same 403 for all methods/paths = blanket rule; varies per path = ACL 4. **Response size** -- baseline the 403 response size. Any size change during testing = different code path hit WAF/proxy-level blocks are bypassable. App-level `if (!user.isAdmin) return 403` generally is not. ## Interpreting Results Status code alone is insufficient. Compare **status code + response body size + response time**: - Same status, different size = backend processed differently (investigate body) - 200 with same size as 403 = may be a generic error page, read the body - 302/301 = auth redirect, not a bypass …
Read the whole file at its exact version.
How to install
mdr add dreadnode/capabilities/403-bypass@sha256:665ce5921cd3f078The line at the top of this page pins the label git:20260504.2a64374, which is what most people want. This one pins the sha256 fingerprint of the contents instead, so it survives a label being moved. Either way the exact version is written to mdr.lock, and mdr install downloads and checks those contents again, so it installs them exactly or stops with an error.
[](https://markdownregistry.com/a/art_x6kxaq7tsyvhhs2s)
3 badge image fetches in 30 days. What the badge shows.
Versions
The registry has recorded 1 version of this file, committed on May 4, 2026.
Audit of the latest version
- pass: Frontmatter block present
- pass: Frontmatter declares a name
- pass: Frontmatter declares a description
- pass: Size between 200 bytes and 200 KB (9828 bytes)
- pass: No zero-width or bidi control characters
- pass: No instruction hidden inside an HTML comment
- pass: No link to an exfiltration or paste host
- pass: No credential-shaped string
- pass: No instruction to send local credentials anywhere
- pass: No text hidden with inline styles
- pass: No prompt-injection phrasing
- pass: No curl or wget piped into a shell
- pass: No recursive delete of root, home or parent
- pass: No instruction to read or print local credentials
- pass: No base64 blob over 200 characters
- pass: No link to a raw IP address
- pass: No script tag
Source
dreadnode/capabilities · 22 stars · license MIT · pushed 2026-11-02 · branch main
API
GET https://markdownregistry.com/api/v1/artifacts/art_x6kxaq7tsyvhhs2s GET https://markdownregistry.com/api/v1/resolve?ref=dreadnode/capabilities/403-bypass GET https://markdownregistry.com/api/v1/blob/665ce5921cd3f07814131b063845d31770ec2fc1a509710f15aea2e50c3a09cc
Your AI assistant does the legwork. You hear about the deals worth your word. Hand yours the standing instructions at modelranch.com and it joins the network that reads files like this one.
Guides: the SKILL.md format and its required fields · what to check before you install a skill · how to pin a skill to an exact version · where to find agent skills · keeping a team on the same skills · which agent file does what.