On March 31, 2026, attackers published compromised versions of axios — npm's most downloaded HTTP client — containing a Remote Access Trojan hidden in a transitive dependency. The payload exfiltrated environment variables, SSH keys, and API credentials from every developer who ran npm install.
I run an MCP server with API keys for 55 connected services. When I saw the advisory, I realized how exposed the entire AI tool ecosystem is to supply chain attacks.
So I built 0nDefender.
The Key Insight: Timing
Most security tools scan AFTER packages are installed. The axios attack used a postinstall script — by the time your scanner runs, the malicious code has already executed.
0nDefender's core mechanism is a preinstall hook. It runs BEFORE npm resolves, downloads, or installs anything.
{
"scripts": {
"preinstall": "npx 0nmcp@latest defender scan --lockfile"
}
}
The hook reads package-lock.json, cross-references against known malicious versions, pattern-matches against typosquatter names, and blocks anything suspicious.
[email protected] would have been blocked. plain-crypto-js would never have been downloaded. The RAT would never have executed.
4 Security Layers
0nSeal — The preinstall hook. Prevention at the gate.
0nWatch — Continuous scanning against npm advisory database and GitHub Security Advisories. Every 6 hours.
0nVaultGuard — Health-checks every API key via zero-knowledge probing. Keys never leave your machine. Every 12 hours.
0nAlert — Real-time notifications via email, Slack, or Discord.
Why MCP Servers Are High-Value Targets
If you run a Claude Desktop MCP server, your environment probably contains API keys for AI providers, payment processors, databases, CRMs, email services, and cloud infrastructure. One compromised npm package = access to all of them.
Install in 60 Seconds
npm install -g 0nmcp
0nmcp engine verify
Add to Claude Desktop config:
{
"mcpServers": {
"0nMCP": {
"command": "npx",
"args": ["-y", "0nmcp"]
}
}
}
Free. Open source. MIT licensed. No sign-up. No telemetry.
Full writeup: 0nmcp.com/secure-claude
Source: github.com/0nork/0nMCP
Built by RocketOpp LLC. Non-funded. Non-seeded. Just building what the ecosystem needs.
SOCIAL SHARE CARD GENERATOR