MIT krb5 Security Advisory 2011-003
Original release: 2011-03-15
Last update: 2011-03-15
Topic: KDC vulnerable to double-free when PKINIT enabled
CVSSv2 Vector: AV:N/AC:M/Au:N/C:C/I:C/A:C/E:POC/RL:OF/RC:C
CVSSv2 Base Score: 9.3
Access Vector: Network
Access Complexity: Medium
Confidentiality Impact: Complete
Integrity Impact: Complete
Availability Impact: Complete
CVSSv2 Temporal Score: 7.3
Remediation Level: Official Fix
Report Confidence: Confirmed
The MIT Kerberos 5 Key Distribution Center (KDC) daemon is vulnerable
to a double-free condition if the Public Key Cryptography for Initial
Authentication (PKINIT) capability is enabled, resulting in daemon
crash or arbitrary code execution (which is believed to be difficult).
An unauthenticated remote attacker can induce a double-free event,
causing the KDC daemon to crash (denial of service), or to execute
arbitrary code. Exploiting a double-free event to execute arbitrary
code is believed to be difficult.
The KDC in releases krb5-1.7 and later are vulnerable, if they are
configured to respond to PKINIT requests. Earlier releases did not
contain the vulnerable code. Additionally, third-party
preauthentication plugins that generate TYPED-DATA in the e-data field
of a KRB-ERROR message may be vulnerable.
* Upcoming releases in the krb5-1.7, krb5-1.8, and krb5-1.9 series
will contain fixes.
* Apply the following patch:
diff --git a/src/kdc/do_as_req.c b/src/kdc/do_as_req.c
index 46b5fa1..464cb6e 100644
- --- a/src/kdc/do_as_req.c
@@ -741,6 +741,8 @@ prepare_error_as (struct kdc_request_state *rstate, krb5_kdc_req *request,
pad->contents = td[size]->data;
pad->length = td[size]->length;
pa[size] = pad;
+ td[size]->data = NULL;
+ td[size]->length = 0;
This patch is also available at
A PGP-signed patch is available at
This announcement is posted at:
This announcement and related security advisories may be found on the
MIT Kerberos security advisory page at:
The main MIT Kerberos web page is at:
This issue was discovered by Cameron Meadors of Red Hat.
The MIT Kerberos Team security contact address is
<firstname.lastname@example.org>. When sending sensitive information,
please PGP-encrypt it using the following key:
pub 2048R/56CD8F76 2010-12-29 [expires: 2012-02-01]
uid MIT Kerberos Team Security Contact <email@example.com>
In do_as_req.c, the function perpare_error_as() attempts to decode the
e_data field both as preauth data and as typed data. If the e_data
contents are typed data, they are converted to preauth data. This
conversion can free pointers to the typed data items, and free them
again when cleaning up the preauth data during function exit.
2011-03-15 original release
Copyright (C) 2011 Massachusetts Institute of Technology
+*mit-krb5-1.9-r2 (16 Mar 2011)
+*mit-krb5-1.8.3-r4 (16 Mar 2011)
+ 16 Mar 2011; Eray Aslan <firstname.lastname@example.org> +mit-krb5-1.8.3-r4.ebuild,
+ +mit-krb5-1.9-r2.ebuild, +files/CVE-2011-0284.patch:
+ version bump - security bug #359129
=app-crypt/mit-krb5-1.8.3-r4 should be stabilized. Thanks.
Arches, please test and mark stable:
Target keywords : "alpha amd64 arm hppa ia64 m68k ppc ppc64 s390 sh sparc x86"
Stable for HPPA.
amd64 done. Thanks Agostino
Thanks, everyone. Added to existing GLSA request.
This issue was resolved and addressed in
GLSA 201201-13 at http://security.gentoo.org/glsa/glsa-201201-13.xml
by GLSA coordinator Sean Amoss (ackle).