CVE-2024-38829 - Vulnerability in Spring LDAP Allows Data Exposure for Case Sensitive Comparisons

The CVE-2024-38829 vulnerability is a critical security flaw affecting Spring LDAP versions 2.4. through 2.4.3, 3.. through 3..9, 3.1. through 3.1.7, and 3.2. through 3.2.7, and all versions prior to 2.4.. The vulnerability exposes sensitive data due to case-sensitive comparisons, by using Locale-dependent behavior in String.toLowerCase() and String.toUpperCase() methods. This issue is closely related to the CVE-2024-38820 vulnerability, which provides more details about the security problem: https://spring.io/security/cve-2024-38820

Code Snippet

The vulnerability exists due to incorrect usage of the toLowerCase() and toUpperCase() methods. An example of vulnerable code can be:

public class LdapUser {
    private String userName;

    public LdapUser(String userName) {
        this.userName = userName.toLowerCase();
    }

    public boolean isTheSameUser(String userToCompare) {
        return this.userName.equalsIgnoreCase(userToCompare.toLowerCase());
    }
}

In this code, the toLowerCase() method is used to convert the string to lower case, which may lead to incorrect comparisons based on the system's default Locale.

Exploit Details

An attacker can perform a successful exploit by passing specially crafted input to the vulnerable system, which will then expose sensitive data. The system can allow unintended columns to be queried, potentially causing information disclosure and leading to unauthorized access to the system.

For example, if a system has user authentication based on LDAP, an attacker can send the crafted input:

'johndoe' == 'JOHNDOE'    // Exploit: converts both to the same lowercase string

The case-sensitive comparison fails, and sensitive information about user "johndoe" may be exposed to the attacker.

Mitigation

To mitigate this vulnerability, developers must use the toLowerCase(Locale.ENGLISH) and toUpperCase(Locale.ENGLISH) methods. By using these method overloads, the conversion is guaranteed to be Locale-independent, preventing any unexpected behavior during the comparisons.

The above code snippet should be replaced with

public class LdapUser {
    private String userName;

    public LdapUser(String userName) {
        this.userName = userName.toLowerCase(Locale.ENGLISH);
    }

    public boolean isTheSameUser(String userToCompare) {
        return this.userName.equalsIgnoreCase(userToCompare.toLowerCase(Locale.ENGLISH));
    }
}

Additionally, it is highly recommended to update Spring LDAP to the latest version to ensure other issues and vulnerabilities are resolved.

Original References

For more information regarding this vulnerability, please refer to the Spring security advisory related to CVE-2024-38820: https://spring.io/security/cve-2024-38820

For details on how to update your Spring LDAP version, please visit the official Spring LDAP website: https://projects.spring.io/spring-ldap/

Timeline

Published on: 12/04/2024 21:15:24 UTC
Last modified on: 12/10/2024 15:15:07 UTC