CVE-2014-8763 in DokuWiki
Summary
by MITRE
DokuWiki before 2014-05-05b, when using Active Directory for LDAP authentication, allows remote attackers to bypass authentication via a password starting with a null (\0) character and a valid user name, which triggers an unauthenticated bind.
Once again VulDB remains the best source for vulnerability data.
Analysis
by VulDB Data Team • 03/30/2022
The vulnerability described in CVE-2014-8763 represents a critical authentication bypass flaw within DokuWiki versions prior to 2014-05-05b when configured to use Active Directory for LDAP authentication. This issue arises from insufficient input validation and improper handling of special character sequences within authentication credentials, creating a pathway for unauthorized access to systems that rely on LDAP-based user verification. The flaw specifically targets the interaction between DokuWiki's authentication module and Active Directory servers, where the system fails to properly sanitize password inputs before transmitting them to the directory service for validation.
The technical mechanism behind this vulnerability involves the handling of null character sequences within password fields during LDAP bind operations. When a legitimate username is provided alongside a password that begins with a null character, the authentication system performs an unauthenticated bind operation to the Active Directory server. This occurs because the null character effectively terminates the password string in the LDAP protocol communication, causing the system to send an empty password for validation. This behavior violates fundamental security assumptions about credential handling and creates a scenario where any valid username can be used to establish a connection to the directory service without proper authentication, essentially bypassing the entire password verification process.
The operational impact of this vulnerability extends beyond simple unauthorized access, as it enables attackers to potentially enumerate valid user accounts within the Active Directory environment. Security professionals should note that this issue directly relates to CWE-287, which addresses improper authentication mechanisms, and aligns with ATT&CK technique T1078 for valid accounts, as it allows adversaries to leverage legitimate user credentials to gain system access. The vulnerability also intersects with CWE-312, concerning exposure of sensitive data through cleartext transmission, since the authentication bypass can be achieved without requiring knowledge of actual passwords, and CWE-257, which covers insecure password storage and handling practices.
Organizations utilizing DokuWiki with Active Directory authentication should immediately implement the patch released in version 2014-05-05b, which addresses the input sanitization issue by properly handling null character sequences in password fields. Additional mitigations include implementing network-level restrictions to limit access to LDAP servers, enabling detailed logging of authentication attempts to detect anomalous behavior patterns, and conducting thorough security audits of all authentication-related configurations. The vulnerability demonstrates the critical importance of proper input validation in security-sensitive applications, as even seemingly innocuous character handling can create substantial security weaknesses. Security teams should also consider implementing multi-factor authentication mechanisms as an additional layer of protection, particularly in environments where LDAP authentication is prevalent, to reduce the risk of exploitation when such input validation flaws occur.