Injection Flaws in Fiber with Cockroachdb

Injection flaws occur when untrusted data is sent to an interpreter as part of a command or query. In a Fiber application using CockroachDB, the primary risk is SQL injection through query construction. Because CockroachDB speaks PostgreSQL wire protocol, common PostgreSQL-aware injection patterns apply. If you build queries by concatenating user input into SQL strings, an attacker can manipulate the statement structure, bypass authentication, read or modify data, and in some cases execute administrative commands.

Consider a login endpoint that builds a SQL string directly from request parameters:

// Unsafe query construction in Fiber
app.post('/login', (c) => {
  const { username, password } = c.body;
  const query = `SELECT id, role FROM users WHERE username = '${username}' AND password = '${password}'`;
  const result = await db.query(query);
  // ...
});

An attacker supplying username as ' OR '1'='1 and any password can authenticate without valid credentials. Because CockroachDB supports standard SQL behavior, stacked queries (where supported by the driver) enable additional statements like ; DROP TABLE users; if the driver permits multiple statements. Injection is not limited to SQL: if your application dynamically constructs, for example, a keyspace or table name from user input, injection can affect schema or object references.

Another scenario involves query arguments that are not used as data but as identifiers or schema elements. For instance, dynamic sorting or filtering on column names cannot be parameterized with prepared statement placeholders (which bind only values). If you interpolate such values directly, you expose an injection surface:

// Unsafe dynamic column name in Fiber
app.get('/users', async (c) => {
  const { sortBy } = c.query();
  const sql = `SELECT id, name FROM users ORDER BY ${sortBy}`;
  const result = await db.query(sql);
  c.json(result.rows);
});

Here, an attacker can supply a malicious sortBy value such as 1; DROP TABLE users -- (depending on driver behavior) to alter statement semantics. Even when using an ORM or query builder, if the library exposes escaping for identifiers only through string interpolation, the risk remains. Always validate and strictly limit dynamic identifiers against an allowlist.

SSRF and other server-side risks can compound injection issues. If your application uses user-controlled URLs to form CockroachDB statements (e.g., constructing connection parameters or reading external metadata to build queries), you may inadvertently enable SSRF-assisted injection paths. Treat any data that influences how queries are built—whether as values, identifiers, or configuration—as untrusted input.

Finally, error messages returned by CockroachDB can disclose schema details that aid further exploitation. Ensure your Fiber error handling does not expose raw database errors to clients, and use structured logging instead of leaking stack traces or SQL snippets in responses.

Remediation focuses on strict separation of code and data. For queries that use user input as values, always use prepared statements with parameterized queries. In Fiber, this typically means using your database driver’s placeholder syntax and passing values separately:

// Safe parameterized query in Fiber with CockroachDB
app.post('/login', async (c) => {
  const { username, password } = c.body;
  const result = await db.query('SELECT id, role FROM users WHERE username = $1 AND password = $2', [username, password]);
  if (result.rows.length === 0) {
    return c.status(401).json({ error: 'Invalid credentials' });
  }
  // ...
});

Note the use of $1, $2 placeholders (CockroachDB/PostgreSQL style) and an array of values. This ensures the driver handles escaping and type formatting, preventing injection regardless of input content.

For dynamic identifiers (such as column or table names), you must avoid interpolation entirely. Instead, use an allowlist validation approach:

// Safe dynamic identifier handling in Fiber
const allowedSortColumns = new Set(['id', 'name', 'created_at']);

app.get('/users', async (c) => {
  const { sortBy } = c.query();
  if (!allowedSortColumns.has(sortBy)) {
    return c.status(400).json({ error: 'Invalid sort column' });
  }
  // Identifier is safe because it is validated, not interpolated from raw user input
  const sql = `SELECT id, name FROM users ORDER BY ${sortBy}`;
  const result = await db.query(sql);
  c.json(result.rows);
});

By checking sortBy against a predefined set, you guarantee that only expected identifiers are used. This pattern is essential for any dynamic schema object references.

When using an ORM or query builder, prefer APIs that enforce parameterization and avoid methods that concatenate SQL strings. If your tool generates SQL, verify that it does not allow raw string fragments for values. Regularly update your driver and ORM to benefit from security patches related to CockroachDB compatibility.

Error handling should be configured to prevent verbose database errors from reaching the client. In Fiber, you can centralize error processing:

// Generic error handling to avoid leaking DB details
app.use(async (c, next) => {
  await next();
  if (c.err) {
    c.body = { error: 'Internal server error' };
    c.status = 500;
  }
});

Finally, integrate middleBrick into your workflow to automatically detect injection risks and other issues. Use the CLI to scan from terminal with middlebrick scan <url>, add API security checks to your CI/CD pipeline with the GitHub Action, or scan APIs directly from your IDE using the MCP Server. These tools help you identify injection flaws early, without needing to understand the underlying scanning engine.