offensive-request-smuggling

offensive-request-smuggling is a skill for Claude Code, Codex from SnailSploit/Claude-Red. It costs 0 tokens per session (5,564 once invoked), scanned A, original, MIT.

A checklist for testing HTTP request smuggling, a security flaw where different web servers interpret the same request differently. It covers common length and transfer-encoding conflicts, HTTP/2 cases, and related effects.

In plain words
What is it for?
Use it during authorised testing of proxy and load-balancer setups to check for desynchronisation, cache poisoning, WAF bypasses, credential exposure, and differential responses.
Why use it?
It gives security testers a structured way to identify mismatches between reverse proxies, load balancers, and backend servers.

Skill for Claude CodeCodex

About the project

claude-red is a library of structured skills that give Claude specialized offensive-security methods for areas such as web vulnerabilities, shellcode, exploit development, and identity systems. It is intended for authorized red-team work, bug-bounty triage, security research, CTF preparation, and operator training. Its catalogue contains the project's skills for loading these security specializations into Claude.

SnailSploit/Claude-Red · 3,026 stars · on GitHub

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/snailsploit/claude-red/offensive-request-smuggling
Any agent
npx skills add SnailSploit/Claude-Red --skill offensive-request-smuggling
Clone the repo
git clone --depth 1 https://github.com/SnailSploit/Claude-Red

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 offensive-request-smuggling

README.md
[![agentmods](https://agentmods.dev/badge/skills/snailsploit/claude-red/offensive-request-smuggling.svg)](https://agentmods.dev/skills/snailsploit/claude-red/offensive-request-smuggling)
Your own site
<a href="https://agentmods.dev/skills/snailsploit/claude-red/offensive-request-smuggling"><img src="https://agentmods.dev/badge/skills/snailsploit/claude-red/offensive-request-smuggling.svg" alt="Measured on agentmods" height="20"></a>
Per session 0 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 5,564 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 1 finding. 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 $0.00000 $0.05564
Opus 5 $0.00000 $0.02782
Sonnet 5 $0.00000 $0.01113
Haiku 4.5 $0.00000 $0.00556

Measured 6d ago against content hash 67c54307ca87, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-05, from the pricing page.

Security

Grade A, and why

offensive-request-smuggling 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.

# Using curl with HTTP/3
Skills/web/offensive-request-smuggling/SKILL.md · 772 lines

How it starts

The opening of the file, as written. The whole thing — 772 lines — stays where its author put it; the contents beside it link to each section on GitHub.

SKILL: HTTP Request Smuggling

Metadata

Description

HTTP request smuggling checklist: CL.TE, TE.CL, TE.TE variants, detection with timing and differential responses, WAF bypass, cache poisoning, credential hijacking, and request smuggling via HTTP/2. Use when testing reverse proxy/load balancer configurations.

Trigger Phrases

Use this skill when the conversation involves any of: request smuggling, HTTP smuggling, CL.TE, TE.CL, TE.TE, HTTP/2 smuggling, cache poisoning, WAF bypass, differential response, smuggling detection, proxy desync

Instructions for Claude

When this skill is active:

  1. Load and apply the full methodology below as your operational checklist
  2. Follow steps in order unless the user specifies otherwise
  3. For each technique, consider applicability to the current target/context
  4. Track which checklist items have been completed
  5. Suggest next steps based on findings

Full Methodology

HTTP Request Smuggling

Mechanisms

HTTP Request Smuggling is a vulnerability that occurs when front-end and back-end servers interpret HTTP requests differently, leading to a desynchronization in the HTTP request processing chain. This desynchronization allows attackers to "smuggle" requests to the back-end server, potentially bypassing security controls or manipulating how other users' requests are processed.

graph TD
    A[Client] -->|HTTP Request| B[Front-end Server]
    B -->|Interpreted Request| C[Back-end Server]
    B -->|Different Interpretation| D[Desynchronization]
    D -->|Smuggled Request| C
    D -->|Security Bypass| E[Unauthorized Access]
    D -->|Queue Poisoning| F[Response Hijacking]

Request smuggling vulnerabilities arise from inconsistencies in how servers parse and interpret HTTP messages, particularly regarding:

  • Transfer-Encoding (TE) header: Indicates chunked encoding
  • Content-Length (CL) header: Specifies the length of the message body
  • Header parsing: Different handling of whitespace, newlines, and malformed headers

Read the full file on GitHub · 772 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 · 772 lines · 0 tokens per session scan A 67c54307ca87

Subscribe to this mod's changes

offensive-request-smuggling is a skill published in the GitHub repository SnailSploit/Claude-Red (3,026 stars, last pushed 6d ago), licensed MIT. It costs nothing until one of its globs matches a file; then it loads 5,564 tokens. 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 2026-08-30.

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