dependency-confusion

dependency-confusion is a skill for Claude Code, Codex from miru-zero/zero-brain. It costs 56 tokens per session (2,372 once invoked), scanned A, a copy of dependency-confusion, MIT.

A security-testing guide for dependency confusion, a supply-chain attack in which an internal package name is taken by a malicious package on a public package registry. It covers package files, lockfiles, registry settings, and authorized testing methods.

In plain words
What is it for?
Use it to review npm, Python, Ruby, Maven, Composer, or Docker dependencies, test package-resolution risks with non-destructive checks, and plan defensive controls.
Why use it?
It helps reveal when a build or deployment could install an attacker-controlled package instead of the intended private one.

Skill for Claude CodeCodex

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/miru-zero/zero-brain/dependency-confusion
Any agent
npx skills add miru-zero/zero-brain --skill dependency-confusion
Clone the repo
git clone --depth 1 https://github.com/miru-zero/zero-brain

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 dependency-confusion

README.md
[![agentmods](https://agentmods.dev/badge/skills/miru-zero/zero-brain/dependency-confusion.svg)](https://agentmods.dev/skills/miru-zero/zero-brain/dependency-confusion)
Your own site
<a href="https://agentmods.dev/skills/miru-zero/zero-brain/dependency-confusion"><img src="https://agentmods.dev/badge/skills/miru-zero/zero-brain/dependency-confusion.svg" alt="Measured on agentmods" height="20"></a>
Per session 56 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 2,372 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 1 finding. Scan, not verified.
Origin 95% copy Near-identical to another mod 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 $0.00056 $0.02372
Opus 5 $0.00028 $0.01186
Sonnet 5 $0.00011 $0.00474
Haiku 4.5 $0.00006 $0.00237

Measured 3d ago against content hash d4ca650064f2, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

dependency-confusion 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 3d 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 "https://search.maven.org/solrsearch/select?q=g:com.example+AND+a:internal-lib&rows=1&wt=json"
Origin

This is a copy

95% identical to dependency-confusion — 4 lines differ, which has more behind it and is treated as the original. This page carries a canonical link to it rather than competing with it.

skills/dependency-confusion/SKILL.md · 179 lines

How it starts

The opening of the file, as written. The whole thing — 179 lines — stays where its author put it; the contents beside it link to each section on GitHub.

SKILL: Dependency Confusion — Supply Chain Attack Playbook

AI LOAD INSTRUCTION: Expert dependency-confusion methodology. Covers how private package names leak, how public registries can win version resolution, ecosystem-specific pitfalls (npm scopes, pip extra indexes, Maven repo order), recon commands, non-destructive PoC patterns (callbacks, not data exfil), and defensive controls. Pair with supply-chain recon workflows when manifests or CI caches are in scope. Only use on systems and programs you are authorized to test.

0. QUICK START

What to look for first

  • Manifests listing package names that look internal (short unscoped names, org-specific tokens, product codenames) without a hard-private registry lock.
  • Evidence the same name might exist—or be squattable—on a public registry with a higher semver than the private feed publishes.
  • Lockfiles missing, stale, or not enforced in CI so install/build can drift toward public metadata.

Fast mental model: If the resolver can see both private and public indexes, and version ranges allow it, the “newest” matching version may be the attacker’s.

Routing note: if the task comes from supply-chain, repository exposure, or CI-build recon, first use recon-for-sec to list internal package names and possible public-registry collisions.


1. CORE CONCEPT

  1. Private packages: An organization ships libraries only on an internal registry (or under conventions that imply “ours”), e.g. a scoped name like @org-scope/internal-utils or an unscoped name such as acme-billing-sdk.
  2. Attacker squats the name: The same package name is published on a public registry (npmjs, PyPI, RubyGems, etc.).
  3. Resolver preference: Many setups resolve highest matching version across all configured indexes (or merge metadata), so a public 9.9.9 can beat a private 1.2.3 if ranges allow.
  4. Execution: Package managers run lifecycle scripts (npm preinstall/postinstall, setuptools entry points, etc.) → attacker code runs on developer laptops, CI, or production image builds.

Read the full file on GitHub · 179 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. 3d ago First seen · 179 lines · 56 tokens per session scan A d4ca650064f2

Subscribe to this mod's changes

dependency-confusion is a skill published in the GitHub repository miru-zero/zero-brain (0 stars, last pushed 16d ago), licensed MIT. It adds 56 tokens to every session and 2,372 once invoked, about $0.0003 per session on Opus 5. A static security scan graded it A with 1 finding (makes network calls). It is 95% identical to dependency-confusion, differing in 4 lines, and is treated as a copy.

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