LDAP is a directory service protocol that allows you to search for and access information stored in an LDAP database. It is commonly used to look up users and passwords. LDAP is known for being lightweight and efficient, which makes it a popular choice for businesses. It is designed to scale well and can handle a large number of requests.

LDAP injection targets web applications that generate LDAP statements based on user input. If the application does not properly sanitize the input, an attacker may be able to inject malicious code using SQL injection techniques, which could allow them to modify LDAP statements and potentially gain unauthorized access to information stored in the LDAP database or tree. LDAP injection attacks can potentially compromise the security of the application and the information it holds.

Understanding LDAP Injection

An example of an application vulnerable to LDAP injection is a user authentication system that uses LDAP to authenticate users against a directory server. The application allows users to log in by entering their username and password on the login page. When a user enters their credentials, the application sends an LDAP query to the directory server to check if the provided username and password are valid.

The query looks something like this:

"(&(objectClass=user)(sAMAccountName=<username>)(userPassword=<password>))"

Where and are replaced by the user-provided values.

However, the application does not properly validate the user-provided input and is vulnerable to LDAP injection. An attacker can exploit this vulnerability by providing malicious input in the username and password fields.

For example, the attacker could enter the following in the username field:

"*)(|(objectClass=user))"

And leave the password field blank. This will cause the LDAP query to become:

"(&(objectClass=user)(sAMAccountName=*)(|(objectClass=user))(userPassword=))"

The query now returns all the user objects in the directory server, allowing the attacker to obtain a list of all the valid usernames in the system. The attacker can then use this information to attempt to brute force the password for each user and potentially gain unauthorized access to the application.

How Vulnerability Occurs

The vulnerability occurs when software or applications use weak or easily guessable password protection. This allows malicious actors to easily gain unauthorized access to the system or application by guessing the password or using a dictionary attack.
One reason this vulnerability occurs is due to a lack of proper password policies and guidelines. Many users choose simple, easy-to-remember passwords, which can be easily guessed or hacked using common password-cracking tools.
Another reason is inadequate security measures, such as not regularly updating password policies or not implementing two-factor authentication. This allows hackers to easily exploit weak passwords and access sensitive information.
Overall, the vulnerability occurs due to a combination of weak password protection and inadequate security measures, allowing malicious actors to gain unauthorized access to systems and applications easily.

Ways LDAP Injection Attack Could Cause Damage

Unauthorized access to sensitive data: By injecting malicious code into an LDAP query, an attacker can gain access to sensitive data such as user passwords, financial information, or confidential business documents.
Data manipulation: An attacker could also manipulate LDAP data, such as modifying or deleting user accounts or changing access permissions to critical systems.
Denial of service: By injecting large or complex queries into the LDAP server, an attacker could overload the system and cause it to crash or become unresponsive, resulting in a denial of service for legitimate users.
Reputation damage: If sensitive data is accessed or manipulated during an LDAP injection attack, the organization may suffer reputational damage and loss of customer trust.

Overall, an LDAP injection attack can cause significant harm to an organization by compromising the security and integrity of its data and systems.

Examples of LDAP Injection

Below are the common example of LDAP injection
Access control injection: This type of LDAP injection involves exploiting vulnerabilities in the authentication and authorization process to bypass access controls and gain unauthorized access to sensitive data or resources. For example, an attacker may use a crafted LDAP query to bypass login authentication and gain access to a restricted user account.
Leaking sensitive data injection: This type of LDAP injection involves exploiting vulnerabilities in the LDAP server or application to extract personal data, such as passwords, credit card numbers, or personally identifiable information (PII). For example, an attacker may use a crafted LDAP query to retrieve sensitive data from a directory server without the user's knowledge or consent.
Privileged access injection: This type of LDAP injection involves exploiting vulnerabilities in the LDAP server or application to grant privileged access to sensitive data or resources. For example, an attacker may use a crafted LDAP query to elevate their own privileges and gain access to restricted user accounts or sensitive data.

LDAP Injection Queries

Below are some examples of LDAP queries and the operators that are used to exploit vulnerabilities, such as § OR and § AND:

OR operator

This query is used to bypass authentication by checking if the username and password are correct or if the email address is correct. It allows an attacker to gain unauthorized access to the system without knowing the correct username and password.

An example of an LDAP injection attack using the OR operator is the following query:

"(&(uid=username)(|(userPassword=)(mail=)))

AND operator

This AND operator query is used to verify the accuracy of both the username and password, as well as the email address. It allows an attacker to gain unauthorized access to the system without knowing the correct username and password.
An example of an LDAP injection attack using the AND operator is the following query:

"(&(uid=)(&(userPassword=password)(mail=)))

Some high-profile LDAP injection attacks include the Yahoo data breach in 2014, which resulted in the exposure of over 500 million user accounts, and the LinkedIn data breach in 2016, which resulted in the exposure of over 100 million user accounts.

Preventing LDAP Injection

To prevent LDAP injection attacks, the following steps can be taken:
Sanitizing inputs
This includes ensuring that all user inputs are properly sanitized and verified before they are utilized in LDAP queries. Any special characters or potential injection strings should be escaped or removed to prevent attackers from modifying the query and gaining unauthorized access to sensitive data.
Limiting access privilege
This implies limiting LDAP access to only those individuals and apps that require it and giving them the bare minimum of access needed to complete their responsibilities. This could help restrict attackers from accessing sensitive data via unauthorized LDAP accounts.
Creating allow list
This involves creating a list of allowed inputs that can be used in LDAP queries and rejecting any inputs that are not on the list. This process can help prevent attackers from using arbitrary inputs to modify the query and gain access to sensitive data.
Use size limits for incoming requests
This involves limiting the size of incoming LDAP requests to prevent attackers from sending large requests that can overwhelm the server and cause a denial of service.
Set up timeout limits
This involves setting timeouts for LDAP requests to prevent attackers from sending requests that take excessively long to process.
Utilizing Cloud One
Cloud One offers a range of security solutions that can assist in identifying potential LDAP injection vulnerabilities and implementing remediation steps. These solutions can help organizations identify and fix vulnerabilities before attackers exploit them.

Cloud One can assist in identifying potential vulnerabilities by utilizing various security tools and services, such as vulnerability scanners, penetration testing, and security assessments. These tools can help identify vulnerabilities in the organization's cloud infrastructure and applications, such as weak passwords, insecure network configurations, and unpatched software.

Once potential vulnerabilities are identified, Cloud One can assist in implementing remediation steps by providing guidance on best practices for securing the organization's cloud environment. This may include implementing strong password policies, configuring network security settings, and implementing regular security updates and patches.

Additionally, Cloud One can provide training and support to help organizations implement and maintain adequate security measures and monitor and respond to any security incidents that may occur. This can aid in keeping the organization's cloud environment safe and compatible with industry standards and laws.

Conclusion

To protect against LDAP injection attacks, it is necessary to check and clean user input to ensure that it does not contain any harmful characters or commands. This is an important step in protecting against these types of attacks.

Developers should also avoid using dynamic LDAP queries and use parameterized queries instead. Also regular testing and monitoring for LDAP injection vulnerabilities can also help prevent attacks.

Finally, preventing LDAP injection attacks requires a combination of proper input validation and sanitization, parameterized queries, and regular testing and monitoring. By implementing these measures, organizations can protect themselves against LDAP injection attacks and the sensitive data they can expose.