Bug ID 675866: WebSSO: Kerberos rejects tickets with 2 minutes left in their ticket lifetime, causing APM to disable SSO

Last Modified: Sep 13, 2023

Affected Product(s):
BIG-IP APM(all modules)

Known Affected Versions:
11.6.1, 11.6.2, 12.0.0, 12.0.0 HF1, 12.1.0 HF1, 12.0.0 HF2, 12.1.0 HF2, 12.0.0 HF3, 12.0.0 HF4, 12.1.1 HF1, 12.1.1 HF2, 12.1.2 HF1, 12.1.2 HF2, 12.1.0, 12.1.1, 12.1.2, 12.1.3, 12.1.3.1, 13.0.0, 13.0.0 HF1, 13.0.0 HF2, 13.0.0 HF3, 13.1.0, 13.1.0.1, 13.1.0.2, 13.1.0.3

Fixed In:
14.0.0, 13.1.0.4, 13.0.1, 12.1.3.2, 11.6.3

Opened: Jul 27, 2017

Severity: 3-Major

Symptoms

Kerberos rejects tickets with 2 minutes left in their ticket lifetime. This causes tickets to be rejected by KDC, causing APM to disable SSO.

Impact

Cannot access the Kerberos-protected resources.

Conditions

This occurs with Kerberos-protected resources using Windows Server 2012-based DC due to issue described in the Microsoft KB: Kerberos authentication fails when the computer tries to request a service ticket from a Windows Server 2012-based DC, https://support.microsoft.com/en-us/help/2877460/kerberos-authentication-fails-when-the-computer-tries-to-request-a-ser.

Workaround

None.

Fix Information

Kerberos SSO (S4U) tickets are not used when the remaining lifetime is less than 5 minutes. Existing tickets with more than half the configured lifetime or at least 1 hour of lifetime remaining are used. If there are no such tickets, then new tickets are acquired and used.

Behavior Change

Guides & references

K10134038: F5 Bug Tracker Filter Names and Tips