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.
npx skills add SecurityTalent/bugskill-ai --skill open-redirectgit clone --depth 1 https://github.com/SecurityTalent/bugskill-aiWrote 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.
[](https://agentmods.dev/skills/securitytalent/bugskill-ai/open-redirect)<a href="https://agentmods.dev/skills/securitytalent/bugskill-ai/open-redirect"><img src="https://agentmods.dev/badge/skills/securitytalent/bugskill-ai/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.
<a href="https://agentmods.dev/skills/securitytalent/bugskill-ai/open-redirect"><img src="https://agentmods.dev/badge/skills/securitytalent/bugskill-ai/open-redirect.svg" alt="Reviewed on agentmods" width="80" height="20"></a>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.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5.1 | $0.00033 | $0.02930 |
| Opus 5.5 | $0.00013 | $0.01172 |
| Sonnet 5.5 | $0.00007 | $0.00586 |
| Haiku 4.5 | $0.00003 | $0.00293 |
Grade C, and why
open-redirect scanned grade C with 2 findings 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 1mo 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.
Cloud metadata endpointhighServer-side request forgery
One request to 169.254.169.254 can return temporary IAM credentials.
# attacker.com returns 302 → http://169.254.169.254/ Makes network callslowCapability
Not a fault in itself. Listed so you know the mod talks to something, and to what.
Not all HTTP clients follow cross-protocol redirects, but `curl` (default) and some libraries do. This is a copy
100% identical to open-redirect — 0 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.
How it starts
The opening of the file, as written. The whole thing — 381 lines — stays where its author put it; the contents beside it link to each section on GitHub.
SKILL: Open Redirect — Expert Attack Playbook
AI LOAD INSTRUCTION: Open redirect techniques. Covers parameter-based redirects, JavaScript sinks, filter bypass, and chaining with phishing, CSRF Referer bypass, OAuth token theft, and SSRF. Often underrated but critical for phishing and as a building block in multi-step exploit chains.
1. CORE CONCEPT
Open redirect occurs when an application redirects users to a URL derived from user input without validation. The trusted domain acts as a "launchpad" for phishing or token theft.
https://trusted.com/redirect?url=https://evil.com
→ User sees trusted.com in the link → clicks → lands on evil.com
2. FINDING REDIRECT PARAMETERS
Common Parameter Names
?url= ?redirect= ?next= ?dest=
?destination= ?redir= ?return= ?returnUrl=
?go= ?forward= ?target= ?out=
?continue= ?link= ?view= ?to=
?ref= ?callback= ?path= ?rurl=
Server-Side Sinks
HTTP 301/302 Location header
PHP: header("Location: $input")
Python: redirect(input)
Java: response.sendRedirect(input)
Node: res.redirect(input)
Client-Side (JavaScript) Sinks
window.location = input
window.location.href = input
window.location.replace(input)
window.open(input)
document.location = input
3. FILTER BYPASS TECHNIQUES
| Validation | Bypass |
|---|---|
Checks if URL starts with / |
//evil.com (protocol-relative) |
Checks domain contains trusted.com |
evil.com?trusted.com or trusted.com.evil.com |
Blocks http:// |
//evil.com, https://evil.com, \/\/evil.com |
Checks URL starts with https://trusted.com |
https://[email protected] (userinfo) |
Regex ^/[^/] (relative only) |
/\evil.com (backslash treated as path in some browsers) |
Django endswith('target.com') |
http://evil.com/www.target.com — URL path ends with target domain |
| Whitelist by domain suffix | Subdomain takeover on *.trusted.com |
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.
- 1mo ago First seen · 381 lines · 33 tokens per session scan C ff08ad872fa5
open-redirect is a skill published in the GitHub repository SecurityTalent/bugskill-ai (13 stars, last pushed 21d ago), licensed MIT. It adds 33 tokens to every session and 2,930 once invoked, about $0.0001 per session on Opus 5.5. A static security scan graded it C with 2 findings (cloud metadata endpoint, makes network calls). It is 100% identical to open-redirect, differing in 0 lines, and is treated as a copy.
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