Bug 1121876 (CVE-2014-4343)

Summary: CVE-2014-4343 krb5: double-free flaw in SPNEGO initiators
Product: [Other] Security Response Reporter: Murray McAllister <mmcallis>
Component: vulnerabilityAssignee: Red Hat Product Security <security-response-team>
Status: CLOSED ERRATA QA Contact:
Severity: low Docs Contact:
Priority: low    
Version: unspecifiedCC: carnil, dpal, dsirrine, jplans, jrusnack, nalin, nathaniel, rmainz, sashaikh, sisharma
Target Milestone: ---Keywords: Security
Target Release: ---   
Hardware: All   
OS: Linux   
Whiteboard: impact=low,public=20140715,reported=20140721,source=debian,cvss2=4.3/AV:N/AC:M/Au:N/C:N/I:N/A:P,fedora-all/krb5=affected,rhel-5/krb5=notaffected,rhel-6/krb5=affected,rhel-7/krb5=affected,cwe=CWE-416
Fixed In Version: Doc Type: Bug Fix
Doc Text:
A double-free flaw was found in the MIT Kerberos SPNEGO initiators. An attacker able to spoof packets to appear as though they are from an GSSAPI acceptor could use this flaw to crash a client application that uses MIT Kerberos.
Story Points: ---
Clone Of: Environment:
Last Closed: 2015-03-06 10:10:32 UTC Type: ---
Regression: --- Mount Type: ---
Documentation: --- CRM:
Verified Versions: Category: ---
oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: ---
Bug Depends On: 1121510, 1121789, 1121879    
Bug Blocks: 1101912, 1121513, 1121882    

Description Murray McAllister 2014-07-22 06:23:03 UTC
A double-free flaw was found in the MIT Kerberos SPNEGO initiators. An attacker able to spoof packets to appear as though they are from an GSSAPI acceptor could use this flaw to crash a client application that uses MIT Kerberos.

It is reported that this issue affects version 1.10 and later.

Upstream commit and further details:

https://github.com/krb5/krb5/commit/f18ddf5d82de0ab7591a36e465bc24225776940f

Comment 1 Murray McAllister 2014-07-22 06:27:19 UTC
Created krb5 tracking bugs for this issue:

Affects: fedora-all [bug 1121879]

Comment 3 Siddharth Sharma 2014-07-25 06:15:36 UTC
spnego_gss_init_sec_context -> init_ctx_cont -> init_ctx_nego -> init_ctx_reselect 

It is possible for unauthenticated attacker to crash the clients, as in the process according to RFC SPNEGO uses pseudo-mechanism which checks which gssapi mechanisms can be used. SPNEGO is not used by default. It requires high complexity to execute such attack as it also involves spoofing Web Server SSL certificate also.

Comment 4 Siddharth Sharma 2014-07-28 06:49:18 UTC
Statement:

This issue did not affect the version of krb5 as shipped with Red Hat Enterprise Linux 5.

Comment 5 Fedora Update System 2014-08-07 15:27:12 UTC
krb5-1.11.3-24.fc19 has been pushed to the Fedora 19 stable repository.  If problems still persist, please make note of it in this bug report.

Comment 6 Fedora Update System 2014-08-07 15:32:45 UTC
krb5-1.11.5-10.fc20 has been pushed to the Fedora 20 stable repository.  If problems still persist, please make note of it in this bug report.

Comment 7 Martin Prpič 2014-10-08 08:40:07 UTC
IssueDescription:

A double-free flaw was found in the MIT Kerberos SPNEGO initiators. An attacker able to spoof packets to appear as though they are from an GSSAPI acceptor could use this flaw to crash a client application that uses MIT Kerberos.

Comment 8 errata-xmlrpc 2014-10-14 08:11:10 UTC
This issue has been addressed in the following products:

  Red Hat Enterprise Linux 6

Via RHSA-2014:1389 https://rhn.redhat.com/errata/RHSA-2014-1389.html

Comment 10 errata-xmlrpc 2015-03-05 10:01:14 UTC
This issue has been addressed in the following products:

  Red Hat Enterprise Linux 7

Via RHSA-2015:0439 https://rhn.redhat.com/errata/RHSA-2015-0439.html