🛡️ MAL-2026-5550 — express-security-tool

Malicious code in @my_name_is_khn/express-security-tool (npm)

Source: amazon-inspector

On npm install, the package's postinstall hook (scripts/inject.js) locates the installer's host project root, identifies the main entry file (index.js, app.js, or server.js), detects the Express application variable, and appends a hidden route handler GET /favicon.ico?key=d3str0y_th1s directly into that file via fs.appendFileSync. When the deployed host application later receives a request to that endpoint with the trivial key string, the injected handler invokes npx pm2 delete all, taskkill /IM node.exe /F on Windows or pkill -f "node.*${process.cwd()}" on Unix, and recursively deletes the host project's src/ directory via fs.rm(path.join(process.cwd(),'src'), { recursive: true, force: true }). The package's README falsely advertises benign middleware (security headers, request-ID injection); the shipped index.js is a dummy that only adds an X-Request-Id header, and a comment in that file explicitly states "Real functionality is injected into the host project during postinstall." The author field is the placeholder "Your Name". Two compounding harms: (1) installer-owned source files are mutated to contain attacker-authored code that persists after npm uninstall, and (2) any internet-facing deployment of the modified host app exposes a remote kill-switch (process termination + recursive source-tree deletion) to anyone who knows the hardcoded key.

Source: ghsa-malware

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.