free-anthropic-claudenpm
free-anthropic-claude is a confirmed malicious npm package (MAL-2026-6260) that steals credentials and exfiltrates sensitive data (malicious versions 1.0.0, 4.7.7, 4.7.9…). Do not install it — remove it immediately and rotate any exposed credentials.
Malicious code in free-anthropic-claude (npm)
What this malware does
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:
- 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 asmain.py, then executed via a detached Python process. - 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), runswinget install Python.Python.3.12(Windows), orbrew install python3(macOS) — installing an entire Python distribution solely to run the C2-supplied payload. - macOS privacy bypass: on Darwin, sqlite3-INSERTs rows into
~/Library/Application Support/com.apple.TCC/TCC.dbgranting 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. - Crypto-wallet stealer toolchain: pip-installs
bip-utils,mnemonic,pycryptodome,psutil,eth-accountwith--break-system-packages, the canonical libraries for BIP39 seed-phrase parsing, BIP32 derivation, and Ethereum private-key handling. - Persistence: writes a
.cs_v2marker andmain.pyunder disguised paths impersonating system directories (~/.local/share/com.apple.syncon macOS,~/.local/share/prometheuson Linux,%LOCALAPPDATA%\Microsoft\Windows Security\Healthon Windows). Subsequentrequire()of the package re-spawns the detached Python payload. - 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.
Malicious versions
Indicators of compromise (SHA-256)
Detection & response playbook
Credential / info stealerFind it
Scan your lockfiles (package-lock.json, pnpm-lock.yaml, yarn.lock, requirements.txt, poetry.lock, etc.) and build artifacts for free-anthropic-claude (26 malicious versions). O3 Security's supply-chain scanner checks every dependency against known-malicious package intelligence at install time and in CI, flagging free-anthropic-claude across your stack and pipelines.
If you installed it — respond
free-anthropic-claude is built to steal secrets, so assume every credential the build or runtime could read is compromised. Remove it from your project and lockfile, then rotate ALL exposed secrets — npm/registry tokens, cloud keys, CI/CD secrets, SSH keys, and any .env values — from a known-clean machine. Audit logs for unauthorized use of those credentials.
Did it already run?
If free-anthropic-claude was ever installed, its post-install/runtime payload may have already executed. O3's L7 egress monitoring and runtime eBPF sensors detect the credential exfiltration or command-and-control callback after install and block the malicious outbound channel, so you catch and contain the actual compromise — not just the presence of the package.
How O3 protects you
O3 blocks free-anthropic-claude before install through its supply-chain scanner, and if it has already run, detects and severs the exfiltration or C2 callback at runtime through L7 egress monitoring and eBPF.
Frequently asked questions
Campaign
References
Credits
- Amazon Inspector · finder
- OpenSSF: Package Analysis · finder
Detect & block this
O3 blocks free-anthropic-claude-class packages before install and in CI — and if it already ran, its runtime egress monitoring catches the credential exfiltration and severs the channel.