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Posted on 23 November 2012
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FreeBSD-SA-12:07.hostapd Security Advisory
The FreeBSD Project
Topic: Insufficient message length validation for EAP-TLS messages
Category: contrib
Module: wpa
Announced: 2012-11-22
Credits: Timo Warns, Jouni Malinen
Affects: FreeBSD 8.0 and later.
Corrected: 2012-11-22 22:52:15 UTC (RELENG_8, 8.3-STABLE)
2012-11-22 22:52:15 UTC (RELENG_8_3, 8.3-RELEASE-p5)
2012-11-22 22:52:15 UTC (RELENG_9, 9.1-PRERELEASE)
2012-11-22 22:52:15 UTC (RELENG_9_0, 9.0-RELEASE-p5)
2012-11-22 22:52:15 UTC (RELENG_9_1, 9.1-RC1-p1)
2012-11-22 22:52:15 UTC (RELENG_9_1, 9.1-RC2-p1)
2012-11-22 22:52:15 UTC (RELENG_9_1, 9.1-RC3-p1)
CVE Name: CVE-2012-4445
For general information regarding FreeBSD Security Advisories,
including descriptions of the fields above, security branches, and the
following sections, please visit <URL:http://security.FreeBSD.org/>.
I. Background
The hostapd utility is an authenticator for IEEE 802.11 networks. It
provides full support for WPA/IEEE 802.11i and can also act as an IEEE
802.1X Authenticator with a suitable backend Authentication Server
(typically FreeRADIUS).
EAP-TLS is the original, standard wireless LAN EAP authentication
protocol defined in RFC 5216. It uses PKI to secure communication to a
RADIUS authentication server or another type of authentication server.
II. Problem Description
The internal authentication server of hostapd does not sufficiently
validate the message length field of EAP-TLS messages.
III. Impact
A remote attacker could cause the hostapd daemon to abort by sending
specially crafted EAP-TLS messages, resulting in a Denial of Service.
IV. Workaround
No workaround is available, but systems not running hostapd are not
vulnerable.
Note that for FreeBSD 8.x systems, the EAP-TLS authentication method
is not enabled by default. Systems running FreeBSD 8.x are only
affected when hostapd is built with -DEAP_SERVER and as such, binary
installations from the official release are not affected.
V. Solution
Perform one of the following:
1) Upgrade your vulnerable system to 8-STABLE or 9-STABLE, or to
the RELENG_8_3, or RELENG_9_0 security branch dated after the
correction date.
2) To update your vulnerable system via a source code patch:
The following patches have been verified to apply to FreeBSD 8.3
and 9.0 systems.
a) Download the relevant patch from the location below, and verify the
detached PGP signature using your PGP utility.
[FreeBSD 8.x]
# fetch http://security.FreeBSD.org/patches/SA-12:07/hostapd-8.patch
# fetch http://security.FreeBSD.org/patches/SA-12:07/hostapd-8.patch.asc
[FreeBSD 9.x]
# fetch http://security.FreeBSD.org/patches/SA-12:07/hostapd.patch
# fetch http://security.FreeBSD.org/patches/SA-12:07/hostapd.patch.asc
b) Execute the following commands as root:
# cd /usr/src
# patch < /path/to/patch
Recompile the operating system using buildworld and installworld as
described in <URL:http://www.FreeBSD.org/handbook/makeworld.html>.
3) To update your vulnerable system via a binary patch:
Systems running 8.3-RELEASE, 9.0-RELEASE, 9.1-RC1, 9.1-RC2, or 9.1-RC3
on the i386 or amd64 platforms can be updated via the
freebsd-update(8) utility:
# freebsd-update fetch
# freebsd-update install
VI. Correction details
The following list contains the revision numbers of each file that was
corrected in FreeBSD.
Subversion:
Branch/path Revision
- -------------------------------------------------------------------------
stable/8/ r<revision>
releng/8.3/ r<revision>
stable/9/ r<revision>
releng/9.0/ r<revision>
releng/9.1/ r<revision>
- -------------------------------------------------------------------------
VII. References
http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2012-4445
The latest revision of this advisory is available at
http://security.FreeBSD.org/advisories/FreeBSD-SA-12:07.hostapd.asc
