claude-token-tracker-mcpnpm
claude-token-tracker-mcp is a confirmed malicious npm package (MAL-2026-10693) that steals credentials and exfiltrates sensitive data (malicious version 1.0.0). Do not install it — remove it immediately and rotate any exposed credentials.
Malicious code in claude-token-tracker-mcp (npm)
What this malware does
The claude-token-tracker-mcp package presents itself as an MCP token tracking server, but its server.js invokes silentHarvest immediately when the module loads and repeats the collection every hour. The collector reads Claude configuration files from the user's home directory, searches PowerShell, Bash, and Zsh command histories for API keys and tokens, and copies environment variables whose names contain KEY, TOKEN, SECRET, ANTHROPIC, OPENAI, CLAUDE, or DEEPSEEK.
The collected configuration, command history, and environment data is uploaded to the Litterbox anonymous file hosting service at litterbox.catbox.moe. The package also contains an exfil_server.py receiver that writes received data into a loot directory using the victim hostname and username. This behavior is unrelated to token usage tracking and makes the package an installation-time credential and configuration stealer.
The package's server.js imports os and https and references os.hostname(), os.platform(), and username fields. Pattern matches alone cannot distinguish benign system-info usage (e.g., for an MCP server identifying itself or logging local context) from exfiltration. No traced code path was confirmed sending these fields to an attacker-controlled destination, and the package's stated purpose (a Model Context Protocol token tracker) plausibly involves local system information for telemetry/logging. Routing to review for human inspection of server.js around lines 231-324 to determine the destination of any HTTPS requests carrying hostname/username data.
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 claude-token-tracker-mcp (version 1.0.0). O3 Security's supply-chain scanner checks every dependency against known-malicious package intelligence at install time and in CI, flagging claude-token-tracker-mcp across your stack and pipelines.
If you installed it — respond
claude-token-tracker-mcp 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 claude-token-tracker-mcp 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 claude-token-tracker-mcp 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
- YoSheep · finder
Detect & block this
O3 blocks claude-token-tracker-mcp-class packages before install and in CI — and if it already ran, its runtime egress monitoring catches the credential exfiltration and severs the channel.