hunt-websocket

hunt-websocket is a skill for Claude Code, Codex from uphiago/recon-skills. It costs 95 tokens per session (5,149 once invoked), scanned A, original, MIT.

A security-testing guide for WebSocket connections, which let browsers and servers exchange messages in real time.

In plain words
What is it for?
It is for reviewing live features such as chat, trading, games, checkout, and other applications using ws:// or wss:// endpoints.
Why use it?
It helps find missing origin checks, weak authentication, message-level authorization gaps, and unsafe handling of connection upgrades.

Skill for Claude CodeCodex

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

Good fit It is for reviewing live features such as chat, trading, games, checkout, and other applications using ws:// or wss:// endpoints.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/uphiago/recon-skills/hunt-websocket
About the project

Recon Skills is a pack of security-testing skills covering reconnaissance, web applications, APIs, authentication, vulnerability validation, cloud infrastructure, and reporting. Security professionals use it for authorized assessments of systems they own or have written permission to test. The catalogue entries are individual skills from the pack.

uphiago/recon-skills · 1,251 stars · on GitHub · hiago.sh

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 uphiago/recon-skills --skill hunt-websocket
Clone the repo
git clone --depth 1 https://github.com/uphiago/recon-skills

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 hunt-websocket

README.md
[![agentmods](https://agentmods.dev/badge/skills/uphiago/recon-skills/hunt-websocket/github.svg)](https://agentmods.dev/skills/uphiago/recon-skills/hunt-websocket)
Your own site
<a href="https://agentmods.dev/skills/uphiago/recon-skills/hunt-websocket"><img src="https://agentmods.dev/badge/skills/uphiago/recon-skills/hunt-websocket/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 hunt-websocket

Your own site · 80×15
<a href="https://agentmods.dev/skills/uphiago/recon-skills/hunt-websocket"><img src="https://agentmods.dev/badge/skills/uphiago/recon-skills/hunt-websocket.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 95 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 5,149 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. Third-party audits
  • NVIDIA SkillSpector warn 7 Sept 2026
SkillSpector: 3 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 YARA Match · line 66
    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.
  • high Prompt Injection · line 94
    Hidden instructions were detected in comments or invisible text. These could contain malicious directives. Manual review is recommended.
    Fix: Audit all comments and invisible characters. Remove any instructions that direct the agent to perform unauthorized actions. Use plain, reviewable content.
  • medium Excessive Agency · line 318
    Skill enables autonomous high-impact decisions without human-in-the-loop verification. Critical operations (destructive commands, financial transactions, data deletion) should require explicit user confirmation.
    Fix: Add human-in-the-loop confirmation for destructive, irreversible, or high-impact operations. Never auto-execute commands that modify files, send data, or alter system state.
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 $0.00095 $0.05149
Opus 5 $0.00048 $0.02575
Sonnet 5 $0.00019 $0.01030
Haiku 4.5 $0.00010 $0.00515

Measured 6d ago against content hash db980d05ba31, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-10, from the pricing page.

Security

Grade A, and why

hunt-websocket 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 6d 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 --max-time 30 --connect-timeout 10 -sI -o /dev/null -w "%{http_code}\n" \
redteam/hunt-websocket/SKILL.md · 325 lines

How it starts

The opening of the file, as written. The whole thing — 325 lines — stays where its author put it; the contents beside it link to each section on GitHub.

HUNT-WEBSOCKET — WebSocket Security

Crown Jewel Targets

CSWSH (Cross-Site WebSocket Hijacking) with a cookie-authenticated handshake and no CSRF/per-connection token = High–Critical (real-time exfil of any logged-in victim's data).

Highest-value chains:

  • CSWSH → data exfil / ATO — handshake authenticates via ambient cookie, no CSRF token, Origin not enforced → attacker page opens WS as the victim and streams their messages/PII/tokens. If the stream carries a session/refresh/CSRF token, this escalates to ATO.
  • No per-message auth — HTTP/handshake auth present but individual WS frames are not re-authorized → privileged messages accepted (deleteUser, getSecretConfig).
  • Message tampering — modify in-flight frames (price, qty, userId, amount) in trading/game/checkout apps → financial fraud.
  • socket.io namespace / room authz bypass — connect to a privileged namespace or join another user's room without a permission check → cross-tenant real-time exfil.
  • Handshake-layer Upgrade smuggling — a malformed Upgrade/Connection/Sec-WebSocket-* handshake makes the front proxy and origin disagree on whether an upgrade occurred → request-smuggling tunnel.

Grounding — Reference Cases (read before hunting)

These are public, verifiable references. Use them to calibrate what a real WS finding looks like and how it was proven. Do not invent additional report IDs or payouts.

# Source / ID Class Lesson
1 PortSwigger Web Security Academy — "Cross-site WebSocket hijacking" (research + labs) CSWSH Canonical CSWSH model: cookie-auth handshake + no CSRF token + missing Origin check → attacker reads/sends as victim. The authoritative methodology.
2 Christian Schneider — "Cross-Site WebSocket Hijacking (CSWSH)" (original disclosure/write-up, 2013) CSWSH First public CSWSH technique: cookie-auth handshake + no Origin enforcement; PoC must prove victim-data receipt in the attacker browser, not just a 101.
3 Coda CSWSH (referenced in this repo's hunt-csrf set) CSWSH Real-time collab apps commonly authenticate the socket purely via cookie; Origin allow-listing was the missing control.
4 CVE-2020-7662 — websocket-extensions (Node) ReDoS DoS A crafted Sec-WebSocket-Extensions header triggers catastrophic backtracking — handshake header is an attack surface, not just frames.
5 CVE-2024-37890 — ws (Node) DoS DoS Many handshake request headers exhaust the server; confirms the handshake itself is parser-attackable pre-frames.
6 Outdated socket.io / Engine.IO stacks socket.io Motivates the version-fingerprint step in Phase 7 — fingerprint the version, then check that release's known advisories.

Read the full file on GitHub · 325 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. 6d ago First seen · 325 lines · 95 tokens per session scan A db980d05ba31

Subscribe to this mod's changes

hunt-websocket is a skill published in the GitHub repository uphiago/recon-skills (1,251 stars, last pushed 8d ago), licensed MIT. It adds 95 tokens to every session and 5,149 once invoked, about $0.0005 per session on Opus 5. A static security scan graded it A with 1 finding (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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