unboundcompute/security-agent-skills · skills/auditing-presigned-url-scope-abuse/SKILL.md

auditing-presigned-url-scope-abuse skillA

auditing-presigned-url-scope-abuse is agent-read markdown (skill) from unboundcompute/security-agent-skills: Audit presigned object-storage URLs for scope that grants more than the request intended: a signature that covers a broader key, prefix, or bucket than the user should reach, an overlong expiry, a method or content-type left unconstrained, or a signer identity whose permissions exceed the caller's. Covers presigned GET and PUT URLs for S3 and compatible stores, where the signed policy is the only boundary once the URL leaves the server, and where an attacker who edits the key, reuses the URL, or.

Indexed from public GitHub and served as immutable, content-addressed versions. Install it pinned to an exact SHA-256 with the mdr CLI, and every file is verified against the hash recorded here before it reaches your agent. The deterministic audit below grades the latest version, and the same file always earns the same grade.

How to install

Latest version
mdr add unboundcompute/security-agent-skills/auditing-presigned-url-scope-abuse@git:20260827.b5f41a4
Exact content
mdr add unboundcompute/security-agent-skills/auditing-presigned-url-scope-abuse@sha256:c41e3ab3b292bfcc

Pin to a label to follow the author's releases, or to a sha256 to freeze the exact bytes forever. Either way the resolved hash is written to mdr.lock, and mdr install reproduces it on any machine.

Badge

mdr badge

[![mdr](https://markdownregistry.com/badge/art_b2kij6d334sfe3u4.svg)](https://markdownregistry.com/a/art_b2kij6d334sfe3u4)

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Versions

versioncommittedcommitsizeaudit
git:20260827.b5f41a4 latest2026-08-27 b5f41a4 9,108 BA view

Audit of the latest version

A  17 of 17 checks passed. Deterministic, no model, same answer every run.
  • pass: Frontmatter block present
  • pass: Frontmatter declares a name
  • pass: Frontmatter declares a description
  • pass: Size between 200 bytes and 200 KB (9108 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

GitHub

unboundcompute/security-agent-skills · 5 stars · license MIT · pushed 2026-09-08 · branch main

API

GET https://markdownregistry.com/api/v1/artifacts/art_b2kij6d334sfe3u4
GET https://markdownregistry.com/api/v1/resolve?ref=unboundcompute/security-agent-skills/auditing-presigned-url-scope-abuse
GET https://markdownregistry.com/api/v1/blob/c41e3ab3b292bfcca4b4c13dae4ef56766136b797611bf6dc4dafbc01b23e317

Agents talk at modelranch.com: hand yours the instructions there and it joins the network that reads files like this one.