If you are a Microsoft Windows XP user who is authenticated by an MIT Kerberos v5 realm, you may receive an "Access Denied" error message when you try to access a resource or share in an Active Directory directory service domain.
This problem occurs because multiple Kerberos Ticket-Granting Service Requests (KRB_TGS_REQ) can be sent to a Massachusetts Institute of Technology (MIT) Kerberos v5 Key Distribution Center (KDC) at the same time. If information in any of the most recent requests matches the server name, client name, current time, and microsecond fields of the KRB_TGS_REQ authenticator, the MIT Kerberos v5 KDC will return the "Access Denied" error message.
Service pack information
To resolve this problem, obtain the latest service pack for Microsoft Windows XP. For additional information, click the following article number to view the article in the Microsoft Knowledge Base:
322389 How to obtain the latest Windows XP service pack
A supported hotfix is available from Microsoft. However, this hotfix is intended to correct only the problem that is described in this article. Apply this hotfix only to systems that are experiencing this specific problem. This hotfix might receive additional testing. Therefore, if you are not severely affected by this problem, we recommend that you wait for the next software update that contains this hotfix.
If the hotfix is available for download, there is a "Hotfix download available" section at the top of this Knowledge Base article. If this section does not appear, contact Microsoft Customer Service and Support to obtain the hotfix.
Note If additional issues occur or if any troubleshooting is required, you might have to create a separate service request. The usual support costs will apply to additional support questions and issues that do not qualify for this specific hotfix. For a complete list of Microsoft Customer Service and Support telephone numbers or to create a separate service request, visit the following Microsoft Web site:
Note The "Hotfix download available" form displays the languages for which the hotfix is available. If you do not see your language, it is because a hotfix is not available for that language.
The global version of this hotfix has the file attributes (or later) that are listed in the following table. The dates and times for these files are listed in coordinated universal time (UTC). When you view the file information, it is converted to local time. To find the difference between UTC and local time, use the Time Zone tab in the Date and Time tool in Control Panel.
Date Time Version Size File name -------------------------------------------------------- 20-Mar-2003 08:40 5.1.2600.1188 272,384 Kerberos.dll
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section. This problem was first corrected in Microsoft Windows XP Service Pack 2.
Each authenticator (KRB_AP_REQ), including the ones that are contained in a KRB_TGS_REQ message, must have a different set of these values to avoid being detected as a replay. The other content of the KRB_TGS_REQ message, including the specification where service principal is requested, is not cached. If two KRB_TGS_REQs contain authenticators with the same timestamps, they are seen as a replay attack even if the rest of the authenticator is different (for example, the KRB_TGS_REQs for different principals).