Ldap Injection in Adonisjs with Basic Auth

LDAP Injection occurs when user-controlled input is concatenated directly into LDAP query strings without sanitization or parameterized queries. In AdonisJS, this risk can manifest when you use Basic Auth to bind a user to an LDAP server and then build search filters from request data. Unlike SQL, LDAP queries do not support parameterized prepared statements in most client libraries, so developers must construct filter strings manually, which is error-prone.

Consider a typical AdonisJS route that authenticates via HTTP Basic credentials and then binds to an LDAP server to validate the user. If the username from the request is used directly in the LDAP filter, an attacker can inject malicious filter syntax. For example, a username like admin)(objectClass=*) can break the intended filter structure and cause the server to return unintended entries. This can lead to authentication bypass or information disclosure, exposing whether specific usernames exist in the directory.

In AdonisJS, the vulnerability is often introduced at two stages: first, during the construction of the bind DN or search base using user input; second, when forming the search filter for authorization checks. Because Basic Auth sends credentials in base64-encoded form (not encrypted), interception is trivial on unencrypted channels, but the injection risk is about how the server-side code interprets the provided username or password fields. Attackers may probe endpoints with special LDAP characters such as *, (, ), &, and \ to manipulate the query logic.

Real-world impact includes unauthorized access to directory information, privilege escalation, or enumeration of users. For example, an injection payload like (&(uid=*)(objectClass=person)) appended to a filter can return all person entries, bypassing intended scope limits. Since AdonisJS applications often integrate with LDAP for enterprise authentication, improper handling of these inputs can violate security best practices and expose the system to techniques similar to CVE-2021-22986 (LDAP injection-related logic flaws) or generic injection patterns documented in the OWASP API Security Testing Guide.

To detect such issues programmatically, scanning tools compare the API specification against runtime behavior, identifying endpoints that accept user input and interact with LDAP backends. They flag concatenated string usage in filters and highlight missing input validation. This is especially relevant when OpenAPI specs describe Basic Auth security schemes without clarifying how server-side code handles special characters.

Remediation focuses on strict input validation, avoiding string concatenation for LDAP filters, and using safe binding practices. In AdonisJS, you should treat Basic Auth credentials as untrusted and never directly interpolate them into LDAP queries. Instead, rely on exact-match lookups or parameterized-like approaches using library-safe methods.

Example of vulnerable code to avoid:

// Vulnerable: direct string concatenation
const username = request.input('username');
const password = request.input('password');
const ldapFilter = `(uid=${username})`;
// Unsafe bind or search using ldapFilter

Secure approach using exact bind DN construction and avoiding filters from user input:

// Secure: use a known user pattern and validate format
const ldap = use('LDAPClient');
const username = request.input('username');

// Validate username format to allow only alphanumeric and underscores
if (!/^[a-zA-Z0-9_]+$/.test(username)) {
  throw new Error('Invalid username format');
}

// Construct bind DN deterministically
const bindDn = `uid=${username},ou=people,dc=example,dc=com`;

// Attempt bind with provided password
const bindSuccess = await ldap.bind(bindDn, password);
if (!bindSuccess) {
  return response.unauthorized();
}

// If search is needed, use parameterized-like filters via library methods
const entries = await ldap.search('ou=people,dc=example,dc=com', {
  filter: '(objectClass=person)',
  scope: 'sub'
});

Additional remediation steps include enforcing TLS for the LDAP connection, implementing rate limiting on authentication attempts, and logging failed binds without revealing details. You can integrate these checks into your workflow using the middleBrick CLI to scan your AdonisJS endpoints and review findings related to authentication and input validation. The dashboard can track security scores over time, while the GitHub Action can fail builds if risk thresholds are exceeded, ensuring LDAP-related issues are caught before deployment.

For teams using the Pro plan, continuous monitoring can schedule regular scans of your AdonisJS APIs, and the MCP Server allows you to run checks directly from AI coding assistants, helping maintain secure coding practices across the development lifecycle.