Description

Detects unsafe dynamic module imports in Express.js applications that could lead to remote code execution vulnerabilities. When variables or user-controlled input is used in require() statements, attackers may be able to load arbitrary modules or access files outside the intended directory.

Detection Strategy

• Application must use the Express.js framework (imports 'express' module)

• Identifies require() statements that use variables or expressions rather than static strings

• Checks if the module path in require() could be influenced by external input

• Reports issues when require() arguments can be manipulated to load unintended modules

Vulnerable code example

const express = require('express');
const app = express();

app.get('/plugin', (req, res) => {
    const pluginPath = req.query.name;
    // VULNERABLE: Unsanitized user input passed directly to require()
    const plugin = require(pluginPath);
    ...

✅ Secure code example

const express = require('express');
const app = express();

app.get('/plugin', (req, res) => {
    const pluginName = req.query.name;
    // SECURE: Whitelist of allowed plugins prevents arbitrary file inclusion
    const allowedPlugins = {
        'logger': './plugins/logger.js',...