testing-web-cache-deception SKILL.md skillA
testing-web-cache-deception from unboundcompute/security-agent-skills is an agent skill: a SKILL.md folder an AI agent loads when a task calls for it.
mdr add unboundcompute/security-agent-skills/testing-web-cache-deception@git:20260903.6dac719Pins git:20260903.6dac719 in mdr.lock. Pin the fingerprint instead.
- Audit grade
- A, 17 of 17 checks passed
- Kind
- SKILL.md skill
- Repository
- unboundcompute/security-agent-skills
- Path
skills/testing-web-cache-deception/SKILL.md- Versions recorded
- 1
- Latest version
- git:20260903.6dac719, committed Sep 3, 2026
- Size
- 10,499 bytes
- Repository stars
- 26
- License
- MIT
Test web cache deception, where an attacker crafts a static-looking URL, using an added extension, a path delimiter, or a query variant, that maps to the same authenticated dynamic response while a shared cache, keying on the apparent extension or path, stores that private response and serves it to the attacker. Use when a shared cache sits in front of authenticated content and its rule for what is cacheable can disagree with what the origin treats as the same resource. Covers extension-based…
Collected from public GitHub. Every version is saved exactly as it was and never changes. Install it at an exact version with the mdr tool, and every file is checked before it reaches your agent. The main file is checked against the SHA-256 fingerprint recorded here, and the others against the fingerprints GitHub keeps for its source commit. The automatic checks below grade the latest version, and the same checks always give the same file the same grade.
What the file says
# Testing web cache deception: when a fake file extension caches a private page A shared cache and an origin server can disagree about what a URL is. The origin routes by matching a pattern and often ignores a trailing segment, so a request for an account page with a made-up static suffix still returns the account page, authenticated and personal. The cache, meanwhile, decides what to store by a simpler rule, often the apparent file extension or path prefix, and treats that same URL as a harmless static asset it may cache for everyone. When both are true at once, an attacker lures a logged-in victim to the crafted URL, the origin serves the victim's private response, and the cache stores it under a key the attacker can then request unauthenticated, retrieving the victim's data. This is distinct from cache poisoning: nothing in the response is altered; a private response is simply cached where it should never be. The bug is a cacheability decision that diverges from the origin's notion of the same, authenticated resource. You find it by comparing what the cache stores against what the origin actually served. ## When to use …
Read the whole file at its exact version.
How to install
mdr add unboundcompute/security-agent-skills/testing-web-cache-deception@sha256:eec19c9d543ea961The line at the top of this page pins the label git:20260903.6dac719, which is what most people want. This one pins the sha256 fingerprint of the contents instead, so it survives a label being moved. Either way the exact version is written to mdr.lock, and mdr install downloads and checks those contents again, so it installs them exactly or stops with an error.
[](https://markdownregistry.com/a/art_qltweko244ohtcqb)
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Versions
The registry has recorded 1 version of this file, committed on Sep 3, 2026.
Audit of the latest version
- pass: Frontmatter block present
- pass: Frontmatter declares a name
- pass: Frontmatter declares a description
- pass: Size between 200 bytes and 200 KB (10499 bytes)
- pass: No zero-width or bidi control characters
- pass: No instruction hidden inside an HTML comment
- pass: No link to an exfiltration or paste host
- pass: No credential-shaped string
- pass: No instruction to send local credentials anywhere
- pass: No text hidden with inline styles
- pass: No prompt-injection phrasing
- pass: No curl or wget piped into a shell
- pass: No recursive delete of root, home or parent
- pass: No instruction to read or print local credentials
- pass: No base64 blob over 200 characters
- pass: No link to a raw IP address
- pass: No script tag
Source
unboundcompute/security-agent-skills · 26 stars · license MIT · pushed 2026-09-08 · branch main
API
GET https://markdownregistry.com/api/v1/artifacts/art_qltweko244ohtcqb GET https://markdownregistry.com/api/v1/resolve?ref=unboundcompute/security-agent-skills/testing-web-cache-deception GET https://markdownregistry.com/api/v1/blob/eec19c9d543ea961224ae3656a52ef8c973282ba52864da1209fc5f9df606aef
Your AI assistant does the legwork. You hear about the deals worth your word. Hand yours the standing instructions at modelranch.com and it joins the network that reads files like this one.
Guides: the SKILL.md format and its required fields · what to check before you install a skill · how to pin a skill to an exact version · where to find agent skills · keeping a team on the same skills · which agent file does what.