Web cache deception

SkillSecurity

Trick a CDN/cache into storing a victim's authenticated response at a public URL, then read it. Load on "web cache deception", when a CDN/cache sits in front of an app that serves per-user content, or to test whether private pages can be cached. Signals: `X-Cache`/`CF-Cache-Status` headers, caching by file extension, static-looking suffixes on dynamic endpoints.

Instructions available. Your AI can read the instructions. Execution depends on the setup they require.

Account requirements not reviewed. Check the skill instructions before use; ahel provides instructions and does not run this skill.

Add ahel to your AI once: Claude, ChatGPT, Cursor, Claude Code or Codex. Then ask it to use this.

Then ask your AI: use the Web cache deception skill

What this skill tells your AI

The instructions your AI receives, as published by noorqureshi/sploitagent in skills/web/web-cache-deception/SKILL.md and read by ahel’s review.

When it applies

A caching layer (CDN, reverse proxy) fronts an app that returns per-user content, and the cache decides what to store by URL pattern/extension. If you can make an authenticated response look cacheable, the cache stores it — and anyone can then fetch that victim's data.

Why it works

The cache and the origin disagree about the URL. The cache sees /account.css and thinks "static, cache it"; the origin ignores the .css suffix (or a delimiter) and serves the dynamic /account page. The victim's private response gets stored under a public key you can request.

Method

Confirm the mismatch: request an authenticated page with a static suffix — /account/foo.css, /account%0a.css, /account;foo.js, /account%2ffoo.css. If the origin still returns the account page (not 404), the origin is ignoring the suffix.
Confirm caching: repeat and watch X-Cache/CF-Cache-Status flip to HIT, or a Age header appear. A cached, authenticated response is the vulnerability.
Prove cross-user impact: as the victim, visit the crafted URL once (or have them); then as an unauthenticated attacker request the same URL and receive the victim's private data.
Explore delimiters/normalisation: caches and origins normalise ;, %2f, //, .., trailing dots differently — Param Miner's rules or manual fuzzing find the pair that splits them.
Report with least data: prove one private field leaked; don't hoard victim data.

Gotchas

This is not cache poisoning: deception caches a victim's real response; poisoning injects a malicious response via unkeyed input. Different bug, different report (web-cache-poisoning).
Needs a genuinely cacheable-looking key and an origin that ignores it — confirm both.
Some CDNs cache by content-type, not extension — test path-based tricks too.

Verify success

An unauthenticated request retrieves another user's authenticated content from the cache (HIT/Age present), reproducibly.

References

Omer Gil "Web Cache Deception"; PortSwigger web cache deception labs; CDN caching-rule docs.

Signals

GitHub stars: 20
Forks: 7
Last commit: Sep 2026

Advanced

Item type: skill
Key: web-cache-deception-noorqureshi
Source: github.com/noorqureshi/sploitagent

github.com/noorqureshi/sploitagent