Shellshock in Feathersjs with Cockroachdb

Shellshock (CVE-2014-6271 and related variants) is a command injection vulnerability in Bash that arises when untrusted data is passed to environment variables and then used in shell commands. In a Feathersjs application that uses Cockroachdb, this typically occurs when the framework or its dependencies invoke a shell to interact with external processes or system utilities, and those invocations include values derived from HTTP request parameters or headers without proper sanitization.

Feathersjs is a JavaScript framework for real-time applications that abstracts service logic into hooks and services. When a Feathers service executes a subprocess via Node.js child process methods (e.g., exec, execFile, or spawn) and incorporates user-controlled input into shell commands, it can become a vector for Shellshock. If the application uses Cockroachdb as its data store, the risk surface is similar to other databases, but the exposure depends on how Feathers services construct commands that include database-related values such as instance identifiers, connection strings, or table names.

Consider a Feathers hook that builds a diagnostic command incorporating a Cockroachdb instance ID from the request query or payload:

const { exec } = require('child_process');
app.service('diagnostics').hooks({
  before: {
    create: [context => {
      const instanceId = context.params.query.instanceId;
      exec(`cockroach node status --instance=${instanceId}`, (err, stdout) => {
        if (err) throw err;
        context.result = stdout;
      });
      return context;
    }]
  }
});

In this example, an attacker can supply a malicious instanceId such as foo; cat /etc/passwd or foo && id. Bash will interpret the shell metacharacters, leading to command injection. Because the command string is built using string interpolation, the injected payload executes in the context of the application process. This is a direct consequence of how Feathersjs handles hooks and external process invocation combined with Cockroachdb-specific identifiers or configuration values.

Another scenario involves environment variables used by Cockroachdb client libraries or custom scripts invoked by Feathers services. If a Feathers app sets environment variables from user input before spawning a shell to run Cockroachdb-related tooling, Bash may interpret those variables unexpectedly. For example:

const { exec } = require('child_process');
const username = context.params.query.username;
process.env.COCK_USER = username;
exec('cockroach sql --execute=\"SELECT * FROM users\"', (err, stdout) => {
  // handle result
});

If the username contains Bash special characters or function definitions, and the environment is not hardened, Shellshock can be triggered during the execution of the Cockroachdb command. Feathersjs does not inherently introduce Shellshock, but its service and hook architecture can inadvertently create conditions where unsafe shell usage occurs with Cockroachdb-related operations.

To determine whether your specific combination is at risk, review Feathers service code for shell invocations that incorporate external inputs, especially those related to database operations or configuration. Also check dependencies for any use of Bash in scripts or build steps that might process Cockroachdb connection details.

Remediation focuses on avoiding shell invocation for Cockroachdb-related tasks and validating or sanitizing all inputs that could reach Bash. Replace child process shell execution with safer alternatives such as direct database drivers or parameterized CLI calls without shell interpretation.

Instead of using exec with a shell string, use Node.js child process methods that do not invoke Bash by default, or use a Cockroachdb client library. Here is a safer approach using the Cockroachdb Node.js driver:

const { Client } = require('pg'); // Cockroachdb is Postgres-compatible
app.service('cockroach-data').hooks({
  before: {
    create: [async context => {
      const client = new Client({
        connectionString: process.env.COCK_CONNECTION_STRING
      });
      await client.connect();
      const res = await client.query('SELECT * FROM users WHERE id = $1', [context.data.userId]);
      context.result = res.rows;
      await client.end();
      return context;
    }]
  }
});

If you must invoke Cockroachdb CLI tools, avoid shell interpolation entirely. Use execFile or spawn with an array of arguments:

const { execFile } = require('child_process');
app.service('diagnostics').hooks({
  before: {
    create: [context => {
      const instanceId = context.params.query.instanceId;
      // Validate instanceId format strictly before use
      if (!/^[a-zA-Z0-9_-]+$/.test(instanceId)) {
        throw new Error('Invalid instance ID');
      }
      execFile('cockroach', ['node', 'status', '--instance=' + instanceId], (err, stdout) => {
        if (err) throw err;
        context.result = stdout;
      });
      return context;
    }]
  }
});

Input validation is critical. Enforce strict allowlists for any parameter used in system interactions. For Cockroachdb identifiers, reject any characters outside expected patterns. Additionally, ensure that environment variables are not populated from untrusted sources before invoking any subprocess, whether or not a shell is used.

For CI/CD and development workflows, the middleBrick GitHub Action can be added to your pipeline to scan Feathersjs APIs and detect risky patterns involving shell execution and external calls. This helps catch Shellshock-related issues before deployment without requiring manual code audits for every change.