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

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.