LDAP Authentication Management Best Practices

The Lightweight Directory Access Protocol (LDAP) provides an open-source, cross-platform solution for database access control. It’s a common identity and access management (IAM) tool at the enterprise level but can present significant security problems if proper administration protocols aren’t followed. To address these issues, IT professionals must consider potential threats and follow best practices for LDAP management.

The Basics of LDAP Authentication

User authentication with LDAP works on the basis of a client-server model, in which the client is the system requesting access to information and the server is the LDAP server itself. LDAP servers can store usernames, passwords, attributes and permissions and are often employed to house core user identities for the purpose of IAM.

When users need to access information within a database, they input their credentials and wait for validation. Credentials are compared to the core identities stored in the LDAP database, and authentication occurs if there’s a match. Authenticated credentials grant access to information. If credentials don’t match, authentication doesn’t take place, and users are prevented from interacting with requested data, thus preserving the integrity of the system.

LDAP infrastructure may be housed on the premises of an enterprise or in the cloud. Cloud-based LDAP, or LDAP-as-a-Service, requires no onsite server hardware and is scalable to the needs of individual businesses. Enterprises wishing to use LDAP as a secure authentication method in their IAM protocols can save time, money and maintenance costs by choosing cloud-based LDAP but need to consider and compensate for additional security issues associated with cloud migration.

LDAP Security Concerns to Address

All authentication methods are subject to the risk of unauthorized access. Insider threats are still one of the most common issues facing today’s enterprises, particularly poor password management and phishing attacks. Any action allowing an unauthorized third party to access stored data has the potential to compromise thousands of stored records, including user identities, and can render a previously reliable security protocol worthless before the attack is discovered and stopped.

Hackers may use various types of attacks to undermine LDAP protocols. LDAP injection attacks, similar to SQL injection attacks, involve entering malicious code into fields with the intention of exploiting vulnerabilities in the protocol. When user-submitted data isn’t properly sanitized, it’s possible for hackers to not only gain access to the LDAP database but also modify information within the LDAP tree. In practice, this could allow hackers to access anything within the database, including user identities. Changes to core identity information can lock users out while giving hackers free reign of enterprise data, creating widespread compromise in the system.

A denial-of-service (DoS) attack doesn’t involve unauthorized access but can cripple an enterprise by shutting down legitimate users’ ability to access the LDAP service. Without working LDAP protocols, authentication can’t take place, and users are effectively locked out of critical resources for the duration of the attack.

Directory spoofing is similar to website spoofing, in which hackers redirect connections from legitimate resources to compromised destinations. Directory spoofing involves delivering information appearing to come from the requested database by returning modified data or directing the user to another location. In either case, hackers can obtain credential information and use it to access enterprise databases for the purpose of launching more widespread attacks.

Best Practices to Manage LDAP Authentication

The approach to LDAP management is similar to other IAM protocols and requires adherence to a number of best practices for security measures to be successful:

• Set up automatic provisioning and deprovisioning of user identities • Never re-use identifiers • Consider using an enterprise password manager • Protect passwords during transit with SSL, TSL or a similar security protocol • Use cryptographic hashes to secure stored passwords, and salt the hashes to make them difficult to crack • Sanitize user inputs to prevent the injection of malicious code and subsequent manipulation of the LDAP database • Create and enforce access control policies with clearly defined users and objects, as well as rules for database entry creation and modification • Set up consistent monitoring to identify unauthorized access attempts

Be careful about implementing any controls involving account lockouts, as this may lead to unintentional overloading of the server and denial of service to all users if automatic authentication requests are part of common workflows. Supporting authorized access is part of a robust security protocol and should be taken into account when implementing IAM via LDAP.

Maintaining access control with a LDAP protocol can only be successful when accounts are properly managed and security vulnerabilities are addressed. For IT teams executing and managing enterprise IAM protocols using LDAP authentication, the focus must be on data security and integrity. Putting appropriate controls in place and monitoring network activity strengthens defenses against potential attacks and allows LDAP to function as a strong defense against unauthorized access.

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