web3-token-helpernpm
Malicious code in web3-token-helper (npm) Remove it immediately and rotate any exposed credentials.
What this malware does
The package advertises itself as a Web3 fee utility but its main export is a dropper. index.js line 140 base64-decodes a platform-specific command string and executes it via child_process.exec inside the exported calculateFee() function — the exact call the README documents as the headline usage example (calculateFee(100, 2)). The decoded commands branch on host OS and fetch attacker binaries from https://www.mythicalsgames.com/files/sean/ (a typosquat of the legitimate mythicalgames.com; the path segment sean matches package.json's author: "sean"): on Windows, PowerShell with -W Hidden downloads SvcHostUpdate.exe into the user's Startup folder and runs it (login persistence); on Linux, syslog-service.py is written to ~/.local/share/.syslog, launched with nohup, and registered via @reboot sleep 30 && /usr/bin/python3... in the user's crontab (reboot persistence); on macOS, com.microsoft.VSCodeUpdate-darwin-<arch> is written to /tmp, chmod +x'd, has its quarantine attribute stripped, and is exec'd. Filenames impersonate trusted OS components (SvcHostUpdate, syslog-service, com.microsoft.VSCodeUpdate) to evade casual process inspection. package.json also declares "postinstall": "node install.js", but install.js is absent from the tarball — the postinstall is non-functional; the malicious payload triggers on first call to the documented API rather than at install time.
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.
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 web3-token-helper (5 malicious versions). O3 Security's supply-chain scanner checks every dependency against known-malicious package intelligence at install time and in CI, flagging web3-token-helper across your stack and pipelines.
If you installed it — respond
web3-token-helper 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 web3-token-helper 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 web3-token-helper 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
Detect & block this
O3 blocks web3-token-helper-class packages before install and in CI — and if it already ran, its runtime egress monitoring catches the credential exfiltration and severs the channel.