Lightweight Dirctory Access Protocol (LDAP) Injection

LDAP injection is a type of security vulnerability that occurs when untrusted or malicious data is injected into an application that interacts with an LDAP server. LDAP is a protocol used for accessing and managing directory services, typically used for authentication, authorization, and data retrieval.

In an LDAP injection attack, the attacker manipulates user-supplied input to construct LDAP queries or statements that are executed by the application against the LDAP server. The goal is to exploit improper input validation or sanitization, allowing unauthorized access to sensitive information, modification of data, or even server-side command execution.

The steps involved in an LDAP injection attack are as follows:

1. Identifying LDAP Input: The attacker identifies user-controllable input fields or parameters where LDAP queries are constructed.
2. Malicious Input Construction: The attacker crafts malicious input by inserting specially crafted characters, such as LDAP metacharacters (e.g., *, (, ), |), into the user-supplied data. These characters can alter the structure or behavior of the LDAP query.
3. Injection Point: The attacker injects the malicious input into the LDAP query, exploiting improper input handling by the application.
4. Unauthorized Actions: The injected LDAP query can lead to unauthorized actions, such as bypassing authentication, retrieving sensitive information, modifying directory entries, or executing arbitrary commands on the LDAP server.

To mitigate LDAP injection attacks, the following preventive measures can be implemented:

• Input Validation and Sanitization: Implement strict input validation and sanitization routines to filter out or escape any potentially malicious LDAP metacharacters or escape sequences.
• Parameterized Queries: Utilize parameterized or prepared statements to separate user input from the LDAP query structure, preventing the injection of untrusted data into the query itself.
• Least Privilege Principle: Ensure that the LDAP user account used by the application has limited privileges necessary for its intended tasks, minimizing the potential impact of a successful LDAP injection attack.
• Principle of Least Astonishment: Follow secure coding practices and design principles to avoid unexpected or dangerous behaviors when handling user input or constructing LDAP queries.