The LDAP server in Active Directory in Microsoft Windows 2000 SP4 and Server 2003 SP1 and SP2 responds differently to a failed bind attempt depending on whether the user account exists and is permitted to login, which allows remote attackers to enumerate valid usernames via a series of LDAP bind requests, as demonstrated by ldapuserenum.
Exposure of Sensitive Information to an Unauthorized Actor The product exposes sensitive information to an actor that is not explicitly authorized to have access to that information.