CVE-2009-0845: Input Validation
A null pointer dereference flaw was found in Kerberos's GSS-API spnego security mechanism implemenation. A local user could use this flaw to cause a denial of service (krb5 daemon crash) via invalid ContextFlags for the reqFlags field in the NegTokenInit (RFC 4178).
References: http://krbdev.mit.edu/rt/Ticket/Display.html?user=guest&pass=guest&id=6402
Upstream patch: http://src.mit.edu/fisheye/changelog/krb5/?cs=22099
Other sources
The spnegogssacceptseccontext function in lib/gssapi/spnego/spnegomech.c in MIT Kerberos 5 (aka krb5) 1.5 through 1.6.3, when SPNEGO is used, allows remote attackers to cause a denial of service (NULL pointer dereference and daemon crash) via invalid ContextFlags data in the reqFlags field in a negTokenInit token.
— Red Hat
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade
redhat/krb5to a version that resolves this vulnerability.Fixed in 0:1.6.1-31.el5_3.3
Event History
Frequently Asked Questions
What is the severity of CVE-2009-0845?
CVE-2009-0845 has a high severity rating due to its potential to cause a denial of service through a null pointer dereference.
How do I fix CVE-2009-0845?
To fix CVE-2009-0845, update MIT Kerberos 5 to versions later than 1.6.3 or apply relevant patches provided by your distribution.
What software is affected by CVE-2009-0845?
CVE-2009-0845 affects MIT Kerberos 5 versions 1.5 through 1.6.3.
Can CVE-2009-0845 be exploited remotely?
Yes, CVE-2009-0845 can be exploited remotely by sending invalid ContextFlags data.
What is the impact of CVE-2009-0845?
The impact of CVE-2009-0845 is that it can lead to a daemon crash, causing a denial of service.