Token Leakage in Fiber with Cockroachdb

Token leakage in a Fiber application that uses CockroachDB can occur when authentication tokens or session identifiers are inadvertently exposed through database interactions, logs, or API responses. Because CockroachDB is a distributed SQL database often used in production environments, developers may inadvertently construct database queries or error messages that include raw tokens or sensitive identifiers. For example, using string concatenation to build SQL statements can lead to tokens appearing in query logs or slow query diagnostics on the CockroachDB nodes.

In a Fiber application, routes that handle authentication tokens (e.g., from Authorization headers) and then pass them to CockroachDB—such as storing or looking up session records—must avoid including these tokens in any debug output or ORM-generated logs. If the application logs the full request context including headers before forwarding to CockroachDB, tokens may be persisted in log files that are accessible to unauthorized readers. Similarly, if the API returns detailed database errors to the client, a token might be embedded in an error message that references a user record or session row stored in CockroachDB.

The risk is compounded when the API schema is scanned by middleBrick, which checks for Data Exposure and Input Validation across HTTP endpoints and database interactions. middleBrick can detect whether token-like values appear in responses or whether error messages from CockroachDB contain sensitive data patterns. Since the scanner runs unauthenticated black-box tests, it can identify endpoints where a token might be leaked through verbose error replies or inconsistent handling of authentication headers combined with database operations.

Using OpenAPI/Swagger specifications with full $ref resolution, middleBrick cross-references the declared parameters and responses with runtime findings to highlight mismatches. For instance, if a POST /login route documents that it returns only a token but the actual response includes stack traces or database identifiers from CockroachDB, this discrepancy is flagged as a data exposure finding. The scanner also checks for insecure LLM endpoint handling; if your API routes include an unauthenticated endpoint that forwards tokens to an LLM service, middleBrick’s LLM Security checks will surface that as well.

To reduce exposure, design the Fiber routes to treat tokens as opaque values when interacting with CockroachDB, avoiding any logging or echoing of the token itself. Ensure that error messages returned to clients are generic and do not include SQL state or database identifiers that could aid an attacker in correlating tokens with backend records. Apply input validation to reject malformed tokens early, and use prepared statements or parameterized queries so that token values never become part of the SQL string that might be logged by CockroachDB.

Remediation focuses on preventing tokens from being included in database operations, logs, or error responses. Use parameterized queries with the CockroachDB driver so that token values are sent separately from SQL text. Below is a concrete example using the pgx driver with Fiber and CockroachDB, demonstrating safe query execution without exposing tokens in logs or error messages.

// Example: Safe token storage without leakage into logs or errors
const { Pool } = require('pg');
const express = require('express');
const app = express();

const pool = new Pool({
  connectionString: 'your-cockroachdb-connection-string',
});

app.post('/login', async (req, res) => {
  const authHeader = req.headers['authorization'];
  const token = authHeader && authHeader.split(' ')[1];
  if (!token) {
    return res.status(400).json({ error: 'Missing token' });
  }

  try {
    // Use parameterized query to avoid SQL injection and token leakage in logs
    const result = await pool.query(
      'INSERT INTO user_sessions(user_id, token_hash, expires_at) VALUES($1, $2, $3) RETURNING id',
      [req.user.id, hashToken(token), new Date(Date.now() + 3600000)]
    );
    res.json({ sessionId: result.rows[0].id });
  } catch (err) {
    // Do not expose database details or tokens in the response
    console.error('Session store error:', err.message);
    res.status(500).json({ error: 'Internal server error' });
  }
});

// Example: Safe token validation without echoing token in errors
app.get('/profile', async (req, res) => {
  const authHeader = req.headers['authorization'];
  const token = authHeader && authHeader.split(' ')[1];
  if (!token) {
    return res.status(401).json({ error: 'Unauthorized' });
  }

  try {
    const result = await pool.query(
      'SELECT user_id FROM user_sessions WHERE token_hash = $1 AND expires_at > $2',
      [hashToken(token), new Date()]
    );
    if (result.rows.length === 0) {
      return res.status(401).json({ error: 'Invalid session' });
    }
    // Fetch profile data without referencing the token
    const profile = await pool.query('SELECT id, name FROM users WHERE id = $1', [result.rows[0].user_id]);
    res.json(profile.rows[0]);
  } catch (err) {
    console.error('Profile fetch error:', err.message);
    res.status(500).json({ error: 'Internal server error' });
  }
});

In these examples, the token is never interpolated into SQL strings, preventing it from appearing in CockroachDB logs or slow query diagnostics. Token hashing ensures that even if database rows are exposed, the raw token is not stored. Error handling avoids returning database-specific messages that could reveal query structure or token context. middleBrick can validate that endpoints follow these patterns by checking for secure handling of authentication inputs and inspecting responses for unintended data exposure.

Additionally, configure your Fiber application to avoid logging request headers that contain authorization tokens. Use structured logging that filters sensitive fields before sending logs to storage or monitoring systems. Regularly rotate CockroachDB credentials and session signing keys, and ensure TLS is enforced for all database connections to prevent interception. With these measures, the combination of Fiber, CockroachDB, and proactive scanning using middleBrick reduces the likelihood of token leakage while providing clear remediation guidance when findings appear.