exploiting-ssrf

exploiting-ssrf is a skill for Claude Code from trilwu/secskills. It costs 105 tokens per session (2,632 once invoked), scanned B, original, MIT.

A security-testing guide for server-side request forgery (SSRF), a flaw where a server is tricked into sending requests to places chosen by an attacker. Those places may include private network services or cloud metadata endpoints containing temporary credentials.

In plain words
What is it for?
Use it to assess webhooks, imports, link previews, avatar fetchers, PDF or screenshot generators, and other features that retrieve a user-supplied URL.
Why use it?
It helps test URL-fetching features that could expose internal systems or cloud information that users on the public internet cannot access directly.

Skill for Claude Code

Written for Claude Code: shipped in a Claude Code plugin.

Part of the secskills-offense plugin — 40 skills shipped together

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 skills/trilwu/secskills/exploiting-ssrf
Any agent
npx skills add trilwu/secskills --skill exploiting-ssrf
Clone the repo
git clone --depth 1 https://github.com/trilwu/secskills

Made for: Claude Code.

Or install secskills-offense, the plugin that ships this one along with the rest of its 40 skills.

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 exploiting-ssrf

README.md
[![agentmods](https://agentmods.dev/badge/skills/trilwu/secskills/exploiting-ssrf.svg)](https://agentmods.dev/skills/trilwu/secskills/exploiting-ssrf)
Your own site
<a href="https://agentmods.dev/skills/trilwu/secskills/exploiting-ssrf"><img src="https://agentmods.dev/badge/skills/trilwu/secskills/exploiting-ssrf.svg" alt="Measured on agentmods" height="20"></a>
Per session 105 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 2,632 The whole file, excluding the scripts and references it only reads on demand.
Security scan B 2 findings. 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 5.1 $0.00105 $0.02632
Opus 5 $0.00053 $0.01316
Sonnet 5 $0.00021 $0.00526
Haiku 4.5 $0.00011 $0.00263

Measured 2d ago against content hash f95d5ee13460, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-06, from the pricing page.

Security

Grade B, and why

exploiting-ssrf scanned grade B 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 2d 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 endpointmediumServer-side request forgery

One request to 169.254.169.254 can return temporary IAM credentials.

http://169.254.169.254/latest/meta-data/

Downgraded: this mod is about security review, or the phrase is quoted, so it is likely naming the pattern rather than instructing it.

Makes network callslowCapability

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

rg -n 'requests\.get|urllib|httpx|HttpClient|fetch\(|curl_exec|file_get_contents|WebClient|RestTemplate|http\.Get' -A3
secskills-offense/skills/exploiting-ssrf/SKILL.md · 222 lines

How it starts

The opening of the file, as written. The whole thing — 222 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Exploiting SSRF

SSRF matters because of what the server can reach that you cannot: the cloud metadata endpoint holding role credentials, internal services with no authentication, and the container network. The vulnerability is trivial; the work is in the bypasses and in knowing which internal target converts a curiosity into a compromise.

Only against systems you are authorized to test.

When to Use

  • Any feature that fetches a URL: webhooks, imports, avatar-from-URL, link previews, PDF/screenshot generation, XML/SVG processing, file fetch by URI
  • A parameter contains a URL, hostname, IP, or a path that becomes one
  • Source review finds an outbound HTTP call with a user-influenced target
  • Testing an integration that "calls back" to a customer-supplied endpoint

When NOT to Use

  • Client-side request forgery (CSRF) — different vulnerability entirely
  • The wider web methodology — use testing-web-applications
  • Source review as the main task — use auditing-code-for-vulnerabilities
  • Post-exploitation once you hold cloud credentials — use exploiting-cloud-platforms
  • Actually pivoting into internal systems beyond agreed scope — SSRF reaches further than most scopes intend; confirm before you traverse

Find It First

# Parameters that are, or become, URLs
rg -n 'url|uri|src|href|path|dest|redirect|next|feed|host|domain|callback|webhook|target|image|file|proxy' --type-add 'req:*.txt' -i

# Source review: outbound calls with an influenced target
rg -n 'requests\.get|urllib|httpx|HttpClient|fetch\(|curl_exec|file_get_contents|WebClient|RestTemplate|http\.Get' -A3

Every SSRF test starts with an out-of-band listener, because most SSRF is blind:

# Burp Collaborator, interact.sh, or your own DNS+HTTP logger
interactsh-client -v
# Submit http://<unique>.oast.example/ and watch for DNS and HTTP hits

DNS resolution alone is a positive signal. A DNS lookup with no HTTP request usually means the server resolved the host and then blocked the connection — the SSRF exists and a filter is in the way, which tells you to move to bypasses rather than abandon the parameter.

Read the full file on GitHub · 222 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. 2d ago First seen · 222 lines · 105 tokens per session scan B f95d5ee13460

Subscribe to this mod's changes

exploiting-ssrf is a skill published in the GitHub repository trilwu/secskills (134 stars, last pushed yesterday), licensed MIT. It adds 105 tokens to every session and 2,632 once invoked, about $0.0005 per session on Opus 5. A static security scan graded it B 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 2026-09-03.

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