web-vuln-ssrf

web-vuln-ssrf is a skill for Claude Code, Codex from woohyun212/security-skill. It costs 20 tokens per session (4,322 once invoked), scanned C, original, MIT.

A security-testing guide for finding server-side request forgery, a flaw that lets a server make network requests chosen by an attacker.

In plain words
What is it for?
It covers URL-accepting features, out-of-band confirmation, IP and filter bypasses, internal-service access, and cloud metadata testing on AWS, GCP, or Azure.
Why use it?
It helps authorised testers determine whether a web feature can reach internal services or cloud metadata that users normally cannot access.

Skill for Claude CodeCodex

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

Good fit It covers URL-accepting features, out-of-band confirmation, IP and filter bypasses, internal-service access, and cloud metadata testing on AWS, GCP, or Azure.

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Install with agentmods
npx agentmods add skills/woohyun212/security-skill/web-vuln-ssrf
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 woohyun212/security-skill --skill web-vuln-ssrf
Clone the repo
git clone --depth 1 https://github.com/woohyun212/security-skill

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 web-vuln-ssrf

README.md
[![agentmods](https://agentmods.dev/badge/skills/woohyun212/security-skill/web-vuln-ssrf/github.svg)](https://agentmods.dev/skills/woohyun212/security-skill/web-vuln-ssrf)
Your own site
<a href="https://agentmods.dev/skills/woohyun212/security-skill/web-vuln-ssrf"><img src="https://agentmods.dev/badge/skills/woohyun212/security-skill/web-vuln-ssrf/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 web-vuln-ssrf

Your own site · 80×15
<a href="https://agentmods.dev/skills/woohyun212/security-skill/web-vuln-ssrf"><img src="https://agentmods.dev/badge/skills/woohyun212/security-skill/web-vuln-ssrf.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 20 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 4,322 The whole file, excluding the scripts and references it only reads on demand.
Security scan C 2 findings. A grade says what 26 rules found in the file — not that it is safe.
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 5.1 $0.00020 $0.04322
Opus 5 $0.00010 $0.02161
Sonnet 5 $0.00004 $0.00864
Haiku 4.5 $0.00002 $0.00432

Measured 10d ago against content hash d5f69a2b9473, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-09, from the pricing page.

Security

Grade C, and why

web-vuln-ssrf 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 10d 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.

# Apply when direct 127.0.0.1 or 169.254.169.254 is blocked

Makes network callslowCapability

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

- `curl` installed
web-vuln-ssrf/SKILL.md · 351 lines

How it starts

The opening of the file, as written. The whole thing — 351 lines — stays where its author put it; the contents beside it link to each section on GitHub.

What this skill does

Detects Server-Side Request Forgery (SSRF) vulnerabilities by identifying URL-accepting parameters, confirming blind SSRF via out-of-band (OOB) callbacks, escalating to internal service access, and exploiting cloud instance metadata endpoints (AWS, GCP, Azure). Includes all 11 IP bypass techniques to evade server-side blocklists and filter bypasses, plus chain escalation paths from DNS-only SSRF to cloud credential extraction and RCE.

When to use

  • When a request parameter accepts a URL, hostname, IP address, or domain
  • When a feature fetches remote content (webhook URLs, avatar URLs, PDF generators, link previews, import by URL)
  • When an SVG upload endpoint renders the file server-side
  • When a redirect parameter passes user-controlled URLs to a backend fetch
  • When an API accepts a callback, webhook, src, image, next, or redirect parameter

Prerequisites

  • An out-of-band callback listener (interactsh recommended: interactsh-client)
  • curl installed
  • A valid bug bounty or pentest authorization for the target
  • For cloud metadata testing: the target must be hosted on AWS, GCP, or Azure (check response headers or DNS for cloud provider signals)

Inputs

Variable Required Description
SECSKILL_TARGET Yes Base URL of the target (e.g., https://app.example.com)
SECSKILL_SSRF_PARAM Yes Parameter name that accepts a URL (e.g., url, webhook, src)
SECSKILL_SSRF_ENDPOINT Yes Full endpoint path containing the parameter (e.g., /api/fetch)
SECSKILL_OOB_HOST Yes Your interactsh or Burp Collaborator host for OOB detection
SECSKILL_METHOD Optional HTTP method for the endpoint (default: GET)
SECSKILL_TOKEN Optional Bearer token or session cookie for authenticated endpoints
SECSKILL_OUTPUT_DIR Optional Directory to save results (default: ./output)

Workflow

Step 1: Environment setup and injection point identification

Read the full file on GitHub · 351 lines

Files

What ships with it

1 file beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.

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. 10d ago First seen · 351 lines · 20 tokens per session scan C d5f69a2b9473

Subscribe to this mod's changes

web-vuln-ssrf is a skill published in the GitHub repository woohyun212/security-skill (21 stars, last pushed 4mo ago), licensed MIT. It adds 20 tokens to every session and 4,322 once invoked, about $0.0001 per session on Opus 5. A static security scan graded it C with 2 findings (cloud metadata endpoint, makes network calls). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.

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