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Vulnerability Note VU#419344

MIT Kerberos 5 GSS-API library double-free vulnerability

Overview

The GSS-API library provided with MIT krb5 contains a vulnerability that may allow a remote, authenticated attacker to execute arbitrary code or cause a denial of service.

I. Description

A vulnerability in the way the GSS-API library provided with MIT krb5 handles messages with an invalid direction encoding may result in a double free. According to MIT krb5 Security Advisory MITKRB5-SA-2007-003:

    The kg_unseal_v1() function in src/lib/gssapi/krb5/k5unseal.c frees memory allocated for the "message_buffer" gss_buffer_t when it detects an invalid direction encoding on the message. It does not set the pointer to NULL, nor does it set the length to zero. An application subsequently calling gss_release_buffer() on this gss_buffer_t will cause memory to be freed twice.

    Much code provided with MIT krb5 does not attempt to call gss_release_buffer() when gss_unseal() or gss_unwrap() fails, even though the GSS-API C-bindings specification permits it to do so. The RPCSEC_GSS authentication flavor for the RPC library, introduced in krb5-1.4, does call gss_release_buffer() when gss_unwrap() fails. This allows an authenticated attacker to trigger a double-free situation.

Note that this issue affects all releases of MIT krb5 up to and including krb5-1.6. Other server applications that utilize the RPC library or the MIT GSS-API library provided with MIT krb5 may also be affected.

This vulnerability can be triggered by sending a specially crafted Kerberos message to a vulnerable system.

II. Impact

A remote, authenticated user may be able to execute arbitrary code on an affected system or cause the affected program to crash, resulting in a denial of service. Secondary impacts of code execution include complete compromise of the Kerberos key database.

III. Solution

Apply Patch

A patch can be obtained from MIT krb5 Security Advisory MITKRB5-SA-2007-003. MIT also states that this will be addressed in the upcoming krb5-1.6.1 release.

Systems Affected

VendorStatusDate NotifiedDate Updated
3com, Inc.Unknown4-Apr-2007
AlcatelUnknown4-Apr-2007
Apple Computer, Inc.Vulnerable20-Apr-2007
AttachmateWRQ, Inc.Not Vulnerable4-Apr-2007
AT&TUnknown4-Apr-2007
Avaya, Inc.Unknown4-Apr-2007
Avici Systems, Inc.Unknown4-Apr-2007
Borderware TechnologiesUnknown4-Apr-2007
Charlotte's Web NetworksUnknown4-Apr-2007
Check Point Software TechnologiesUnknown4-Apr-2007
Chiaro Networks, Inc.Unknown4-Apr-2007
Cisco Systems, Inc.Not Vulnerable2-Apr-2007
ClavisterUnknown4-Apr-2007
Computer AssociatesUnknown4-Apr-2007
Conectiva Inc.Unknown4-Apr-2007
Cray Inc.Unknown4-Apr-2007
CyberSafe, Inc.Not Vulnerable4-Apr-2007
D-Link Systems, Inc.Unknown4-Apr-2007
Data Connection, Ltd.Unknown4-Apr-2007
Debian GNU/LinuxVulnerable4-Apr-2007
EMC, Inc. (formerly Data General Corporation)Unknown4-Apr-2007
Engarde Secure LinuxUnknown4-Apr-2007
EricssonUnknown4-Apr-2007
eSoft, Inc.Unknown4-Apr-2007
Extreme NetworksUnknown4-Apr-2007
F5 Networks, Inc.Unknown4-Apr-2007
Fedora ProjectUnknown4-Apr-2007
Force10 Networks, Inc.Not Vulnerable4-Apr-2007
Fortinet, Inc.Unknown4-Apr-2007
Foundry Networks, Inc.Unknown4-Apr-2007
FreeBSD, Inc.Unknown4-Apr-2007
FujitsuUnknown4-Apr-2007
Gentoo LinuxVulnerable4-Apr-2007
Global Technology AssociatesUnknown4-Apr-2007
Heimdal Kerberos ProjectNot Vulnerable4-Apr-2007
Hewlett-Packard CompanyUnknown4-Apr-2007
HitachiNot Vulnerable2-Apr-2007
HitachiNot Vulnerable4-Apr-2007
HyperchipUnknown4-Apr-2007
IBM CorporationUnknown4-Apr-2007
IBM Corporation (zseries)Unknown4-Apr-2007
IBM eServerUnknown4-Apr-2007
Immunix Communications, Inc.Unknown4-Apr-2007
Ingrian Networks, Inc.Unknown4-Apr-2007
Intel CorporationUnknown4-Apr-2007
Internet Security Systems, Inc.Unknown4-Apr-2007
IntotoNot Vulnerable4-Apr-2007
IP FilterUnknown4-Apr-2007
Juniper Networks, Inc.Not Vulnerable4-Apr-2007
KTH Kerberos TeamUnknown4-Apr-2007
Linksys (A division of Cisco Systems)Unknown4-Apr-2007
Lucent TechnologiesUnknown4-Apr-2007
Luminous NetworksUnknown4-Apr-2007
Mandriva, Inc.Vulnerable5-Apr-2007
Microsoft CorporationNot Vulnerable4-Apr-2007
MIT Kerberos Development TeamVulnerable3-Apr-2007
MontaVista Software, Inc.Unknown4-Apr-2007
Multinet (owned Process Software Corporation)Unknown4-Apr-2007
Multitech, Inc.Unknown4-Apr-2007
NEC CorporationNot Vulnerable6-Apr-2007
NetBSDUnknown4-Apr-2007
netfilterUnknown4-Apr-2007
Network Appliance, Inc.Unknown4-Apr-2007
NextHop Technologies, Inc.Unknown4-Apr-2007
NokiaUnknown4-Apr-2007
Nortel Networks, Inc.Unknown4-Apr-2007
Novell, Inc.Unknown4-Apr-2007
OpenBSDUnknown4-Apr-2007
Openwall GNU/*/LinuxNot Vulnerable4-Apr-2007
QNX, Software Systems, Inc.Unknown4-Apr-2007
Red Hat, Inc.Vulnerable2-Apr-2007
Redback Networks, Inc.Unknown4-Apr-2007
Riverstone Networks, Inc.Unknown4-Apr-2007
rPathVulnerable5-Apr-2007
Secure Computing Network Security DivisionUnknown4-Apr-2007
Secureworx, Inc.Unknown4-Apr-2007
Silicon Graphics, Inc.Unknown4-Apr-2007
Slackware Linux Inc.Unknown4-Apr-2007
Sony CorporationUnknown4-Apr-2007
StonesoftUnknown4-Apr-2007
Sun Microsystems, Inc.Unknown4-Apr-2007
SUSE LinuxVulnerable5-Apr-2007
Symantec, Inc.Not Vulnerable5-Apr-2007
The SCO GroupUnknown4-Apr-2007
Trustix Secure LinuxVulnerable6-Apr-2007
TurbolinuxUnknown4-Apr-2007
UbuntuVulnerable4-Apr-2007
UnisysUnknown4-Apr-2007
Watchguard Technologies, Inc.Unknown4-Apr-2007
Wind River Systems, Inc.Unknown4-Apr-2007
ZyXELUnknown4-Apr-2007

References


http://web.mit.edu/Kerberos/advisories/MITKRB5-SA-2007-003.txt
http://secunia.com/advisories/24757/
http://secunia.com/advisories/24735/
http://secunia.com/advisories/24750/
http://secunia.com/advisories/24740/
http://securitytracker.com/alerts/2007/Apr/1017852.html
http://docs.info.apple.com/article.html?artnum=305391
http://secunia.com/advisories/24966/

Credit

This issue is addressed in MIT krb5 Security Advisory MITKRB5-SA-2007-003.

This document was written by Chris Taschner.

Other Information

Date Public:2007-04-03
Date First Published:2007-04-03
Date Last Updated:2007-04-23
CERT Advisory: 
CVE-ID(s):CVE-2007-1216
NVD-ID(s):CVE-2007-1216
US-CERT Technical Alerts: 
Metric:17.85
Document Revision:43

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