# MAL-2026-6260: Malicious code in free-anthropic-claude (npm)


- **Type:** Malicious package
- **Package:** `free-anthropic-claude` (npm)
- **Published:** 20 Jun 2026
- **Also known as:** GHSA-3h58-8ch3-mgp3

## What is MAL-2026-6260?

MAL-2026-6260 is a malicious package in free-anthropic-claude, published on 20 Jun 2026. 

### Official description

This package impersonates the Anthropic Claude SDK (name and description claim to be an 'Official Anthropic Claude SDK wrapper', author is 'anthropic-tools') but ships a multi-stage dropper. The package.json declares `postinstall: node lib/cli.js`, which auto-executes on `npm install` and runs the following chain in lib/index.js:

1. Hardcoded C2 over bare IPs: POSTs to four hardcoded IP addresses (107.189.20.82, 107.189.20.146, 104.194.134.33, 104.194.133.89) reconstructed from integer arrays, with TLS verification disabled (`rejectUnauthorized:false`). The JSON response is base64-decoded and written to disk as `main.py`, then executed via a detached Python process.
2. Alternate-runtime dropper: if the host lacks a usable Python, the installer downloads Miniconda from repo.anaconda.com via curl/wget into `~/.local/share/prometheus/miniconda` (Linux), runs `winget install Python.Python.3.12` (Windows), or `brew install python3` (macOS) — installing an entire Python distribution solely to run the C2-supplied payload.
3. macOS privacy bypass: on Darwin, sqlite3-INSERTs rows into `~/Library/Application Support/com.apple.TCC/TCC.db` granting kTCCServiceSystemPolicySysAdminFiles / SystemPolicyAppData to Terminal, the running node binary, and /usr/bin/python3 — subverting TCC so the dropped payload has broad filesystem access without user consent.
4. Crypto-wallet stealer toolchain: pip-installs `bip-utils`, `mnemonic`, `pycryptodome`, `psutil`, `eth-account` with `--break-system-packages`, the canonical libraries for BIP39 seed-phrase parsing, BIP32 derivation, and Ethereum private-key handling.
5. Persistence: writes a `.cs_v2` marker and `main.py` under disguised paths impersonating system directories (`~/.local/share/com.apple.sync` on macOS, `~/.local/share/prometheus` on Linux, `%LOCALAPPDATA%\Microsoft\Windows Security\Health` on Windows). Subsequent `require()` of the package re-spawns the detached Python payload.
6. Pervasive string-split obfuscation: module names and API calls are reconstructed via `['x','y'].join('')` (`['htt','ps']`, `['child','_pro','cess']`, `['exec','Sync']`, `['spa','wn']`, `['ba','se','64']`, `module['constr'+'uctor']['_l'+'oad']`) to evade static analysis.

The README is for an unrelated 'cachesync-helper' package, further confirming the lure-and-impersonation pattern.

Any computer that has this package installed or running should be considered fully compromised. All secrets and keys stored on that computer should be rotated immediately from a different computer. The package should be removed, but as full control of the computer may have been given to an outside entity, there is no guarantee that removing the package will remove all malicious software resulting from installing it.

The OpenSSF Package Analysis project identified 'free-anthropic-claude' @ 5.0.0 (npm) as malicious.

It is considered malicious because:

- The package executes one or more commands associated with malicious behavior.

## What should I do about MAL-2026-6260?

Remove the package from your dependencies and lockfiles, then rotate any secrets on machines where it was installed.

## Fix prompt for AI coding agents

```text
MAL-2026-6260 is a malicious package: free-anthropic-claude (npm). Every version was published to cause harm.

Task:
1. Search this repository's dependency manifests and lockfiles for the package, including transitive dependencies.
2. If it is present, remove it, regenerate the lockfile with the project's package manager, and replace whatever it was used for.
3. List any CI runners, developer machines or containers that installed it, so their secrets can be rotated.
4. If the package is not used anywhere, say so and change nothing.

Reference: https://insights.sbomify.com/MAL-2026-6260/ (Markdown: https://insights.sbomify.com/MAL-2026-6260/index.md)
```

## Sources

- OSV: https://osv.dev/vulnerability/MAL-2026-6260

---
From sbomify Insights: https://insights.sbomify.com/MAL-2026-6260/
Summaries are generated and may contain mistakes; the official description above is the record.