FreeBSD Security Advisories
2006-Sep-30 13:24 UTC
[FreeBSD-Announce] FreeBSD Security Advisory FreeBSD-SA-06:22.openssh
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============================================================================FreeBSD-SA-06:22.openssh
Security Advisory
The FreeBSD Project
Topic: Multiple vulnerabilities in OpenSSH
Category: contrib
Module: openssh
Announced: 2006-09-30
Credits: Tavis Ormandy, Mark Dowd
Affects: All FreeBSD releases.
Corrected: 2006-09-30 19:50:57 UTC (RELENG_6, 6.2-PRERELEASE)
2006-09-30 19:51:56 UTC (RELENG_6_1, 6.1-RELEASE-p10)
2006-09-30 19:53:21 UTC (RELENG_6_0, 6.0-RELEASE-p15)
2006-09-30 19:54:03 UTC (RELENG_5, 5.5-STABLE)
2006-09-30 19:54:58 UTC (RELENG_5_5, 5.5-RELEASE-p8)
2006-09-30 19:55:52 UTC (RELENG_5_4, 5.4-RELEASE-p22)
2006-09-30 19:56:38 UTC (RELENG_5_3, 5.3-RELEASE-p37)
2006-09-30 19:57:15 UTC (RELENG_4, 4.11-STABLE)
2006-09-30 19:58:07 UTC (RELENG_4_11, 4.11-RELEASE-p25)
CVE Name: CVE-2006-4924, CVE-2006-5051
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
OpenSSH is an implementation of the SSH protocol suite, providing an
encrypted, authenticated transport for a variety of services,
including remote shell access.
II. Problem Description
The CRC compensation attack detector in the sshd(8) daemon, upon receipt
of duplicate blocks, uses CPU time cubic in the number of duplicate
blocks received. [CVE-2006-4924]
A race condition exists in a signal handler used by the sshd(8) daemon
to handle the LoginGraceTime option, which can potentially cause some
cleanup routines to be executed multiple times. [CVE-2006-5051]
III. Impact
An attacker sending specially crafted packets to sshd(8) can cause a
Denial of Service by using 100% of CPU time until a connection timeout
occurs. Since this attack can be performed over multiple connections
simultaneously, it is possible to cause up to MaxStartups (10 by default)
sshd processes to use all the CPU time they can obtain. [CVE-2006-4924]
The OpenSSH project believe that the race condition can lead to a Denial
of Service or potentially remote code execution, but the FreeBSD Security
Team has been unable to verify the exact impact. [CVE-2006-5051]
IV. Workaround
The attack against the CRC compensation attack detector can be avoided
by disabling SSH Protocol version 1 support in sshd_config(5).
There is no workaround for the second issue.
V. Solution
Perform one of the following:
1) Upgrade your vulnerable system to 4-STABLE, 5-STABLE, or 6-STABLE,
or to the RELENG_6_1, RELENG_6_0, RELENG_5_5, RELENG_5_4, RELENG_5_3,
or RELENG_4_11 security branch dated after the correction date.
2) To patch your present system:
The following patches have been verified to apply to FreeBSD 4.11, 5.3,
5.4, 5.5, 6.0, and 6.1 systems.
a) Download the relevant patch from the location below, and verify the
detached PGP signature using your PGP utility.
[FreeBSD 4.11]
# fetch http://security.FreeBSD.org/patches/SA-06:22/openssh4x.patch
# fetch http://security.FreeBSD.org/patches/SA-06:22/openssh4x.patch.asc
[FreeBSD 5.x]
# fetch http://security.FreeBSD.org/patches/SA-06:22/openssh5x.patch
# fetch http://security.FreeBSD.org/patches/SA-06:22/openssh5x.patch.asc
[FreeBSD 6.x]
# fetch http://security.FreeBSD.org/patches/SA-06:22/openssh6x.patch
# fetch http://security.FreeBSD.org/patches/SA-06:22/openssh6x.patch.asc
b) Execute the following commands as root:
# cd /usr/src
# patch < /path/to/patch
# cd /usr/src/secure/lib/libssh
# make obj && make depend && make && make install
# cd /usr/src/secure/usr.sbin/sshd
# make obj && make depend && make && make install
c) Restart the SSH daemon. On FreeBSD 5.x and 6.x, this can be done via
# /etc/rc.d/sshd restart
VI. Correction details
The following list contains the revision numbers of each file that was
corrected in FreeBSD.
Branch Revision
Path
- -------------------------------------------------------------------------
RELENG_4
src/crypto/openssh/deattack.c 1.1.1.1.2.6
src/crypto/openssh/deattack.h 1.1.1.1.2.3
src/crypto/openssh/defines.h 1.1.1.2.2.3
src/crypto/openssh/log.c 1.1.1.1.2.6
src/crypto/openssh/log.h 1.1.1.1.2.4
src/crypto/openssh/packet.c 1.1.1.1.2.7
src/crypto/openssh/ssh_config 1.2.2.10
src/crypto/openssh/ssh_config.5 1.4.2.6
src/crypto/openssh/sshd.c 1.6.2.12
src/crypto/openssh/sshd_config 1.4.2.14
src/crypto/openssh/sshd_config.5 1.5.2.8
src/crypto/openssh/version.h 1.1.1.1.2.14
RELENG_4_11
src/UPDATING 1.73.2.91.2.26
src/sys/conf/newvers.sh 1.44.2.39.2.29
src/crypto/openssh/deattack.c 1.1.1.1.2.5.6.1
src/crypto/openssh/deattack.h 1.1.1.1.2.2.10.1
src/crypto/openssh/defines.h 1.1.1.2.2.2.8.1
src/crypto/openssh/log.c 1.1.1.1.2.5.8.1
src/crypto/openssh/log.h 1.1.1.1.2.3.8.1
src/crypto/openssh/packet.c 1.1.1.1.2.6.8.1
src/crypto/openssh/ssh_config 1.2.2.9.6.1
src/crypto/openssh/ssh_config.5 1.4.2.5.6.1
src/crypto/openssh/sshd.c 1.6.2.11.8.1
src/crypto/openssh/sshd_config 1.4.2.13.6.1
src/crypto/openssh/sshd_config.5 1.5.2.7.4.1
src/crypto/openssh/version.h 1.1.1.1.2.13.6.1
RELENG_5
src/crypto/openssh/auth.h 1.13.2.1
src/crypto/openssh/deattack.c 1.1.1.7.2.1
src/crypto/openssh/deattack.h 1.1.1.3.8.1
src/crypto/openssh/defines.h 1.1.1.7.2.1
src/crypto/openssh/log.c 1.1.1.10.2.1
src/crypto/openssh/log.h 1.5.2.1
src/crypto/openssh/packet.c 1.1.1.14.2.1
src/crypto/openssh/session.c 1.44.2.1
src/crypto/openssh/ssh_config 1.25.2.2
src/crypto/openssh/ssh_config.5 1.15.2.2
src/crypto/openssh/sshd.c 1.37.2.1
src/crypto/openssh/sshd_config 1.40.2.2
src/crypto/openssh/sshd_config.5 1.21.2.2
src/crypto/openssh/version.h 1.27.2.2
RELENG_5_5
src/UPDATING 1.342.2.35.2.8
src/sys/conf/newvers.sh 1.62.2.21.2.10
src/crypto/openssh/auth.h 1.13.8.1
src/crypto/openssh/deattack.c 1.1.1.7.14.1
src/crypto/openssh/deattack.h 1.1.1.3.20.1
src/crypto/openssh/defines.h 1.1.1.7.8.1
src/crypto/openssh/log.c 1.1.1.10.8.1
src/crypto/openssh/log.h 1.5.8.1
src/crypto/openssh/packet.c 1.1.1.14.8.1
src/crypto/openssh/session.c 1.44.8.1
src/crypto/openssh/ssh_config 1.25.2.1.2.1
src/crypto/openssh/ssh_config.5 1.15.2.1.2.1
src/crypto/openssh/sshd.c 1.37.8.1
src/crypto/openssh/sshd_config 1.40.2.1.2.1
src/crypto/openssh/sshd_config.5 1.21.2.1.2.1
src/crypto/openssh/version.h 1.27.2.1.2.1
RELENG_5_4
src/UPDATING 1.342.2.24.2.31
src/sys/conf/newvers.sh 1.62.2.18.2.27
src/crypto/openssh/auth.h 1.13.6.1
src/crypto/openssh/deattack.c 1.1.1.7.6.1
src/crypto/openssh/deattack.h 1.1.1.3.12.1
src/crypto/openssh/defines.h 1.1.1.7.6.1
src/crypto/openssh/log.c 1.1.1.10.6.1
src/crypto/openssh/log.h 1.5.6.1
src/crypto/openssh/packet.c 1.1.1.14.6.1
src/crypto/openssh/session.c 1.44.6.1
src/crypto/openssh/ssh_config 1.25.6.2
src/crypto/openssh/ssh_config.5 1.15.6.2
src/crypto/openssh/sshd.c 1.37.6.1
src/crypto/openssh/sshd_config 1.40.6.2
src/crypto/openssh/sshd_config.5 1.21.6.2
src/crypto/openssh/version.h 1.27.6.2
RELENG_5_3
src/UPDATING 1.342.2.13.2.40
src/sys/conf/newvers.sh 1.62.2.15.2.42
src/crypto/openssh/auth.h 1.13.4.1
src/crypto/openssh/deattack.c 1.1.1.7.4.1
src/crypto/openssh/deattack.h 1.1.1.3.10.1
src/crypto/openssh/defines.h 1.1.1.7.4.1
src/crypto/openssh/log.c 1.1.1.10.4.1
src/crypto/openssh/log.h 1.5.4.1
src/crypto/openssh/packet.c 1.1.1.14.4.1
src/crypto/openssh/session.c 1.44.4.1
src/crypto/openssh/ssh_config 1.25.4.2
src/crypto/openssh/ssh_config.5 1.15.4.2
src/crypto/openssh/sshd.c 1.37.4.1
src/crypto/openssh/sshd_config 1.40.4.2
src/crypto/openssh/sshd_config.5 1.21.4.2
src/crypto/openssh/version.h 1.27.4.2
RELENG_6
src/crypto/openssh/auth.h 1.15.2.2
src/crypto/openssh/deattack.c 1.1.1.7.8.1
src/crypto/openssh/deattack.h 1.1.1.3.14.1
src/crypto/openssh/defines.h 1.1.1.9.2.2
src/crypto/openssh/log.c 1.1.1.13.2.1
src/crypto/openssh/log.h 1.6.2.1
src/crypto/openssh/packet.c 1.1.1.16.2.2
src/crypto/openssh/session.c 1.46.2.2
src/crypto/openssh/ssh_config 1.27.2.2
src/crypto/openssh/ssh_config.5 1.17.2.2
src/crypto/openssh/sshd.c 1.39.2.2
src/crypto/openssh/sshd_config 1.42.2.2
src/crypto/openssh/sshd_config.5 1.23.2.2
src/crypto/openssh/version.h 1.30.2.2
RELENG_6_1
src/UPDATING 1.416.2.22.2.12
src/sys/conf/newvers.sh 1.69.2.11.2.12
src/crypto/openssh/auth.h 1.15.2.1.4.1
src/crypto/openssh/deattack.c 1.1.1.7.12.1
src/crypto/openssh/deattack.h 1.1.1.3.18.1
src/crypto/openssh/defines.h 1.1.1.9.2.1.4.1
src/crypto/openssh/log.c 1.1.1.13.6.1
src/crypto/openssh/log.h 1.6.6.1
src/crypto/openssh/packet.c 1.1.1.16.2.1.4.1
src/crypto/openssh/session.c 1.46.2.1.4.1
src/crypto/openssh/ssh_config 1.27.2.1.4.1
src/crypto/openssh/ssh_config.5 1.17.2.1.4.1
src/crypto/openssh/sshd.c 1.39.2.1.4.1
src/crypto/openssh/sshd_config 1.42.2.1.4.1
src/crypto/openssh/sshd_config.5 1.23.2.1.4.1
src/crypto/openssh/version.h 1.30.2.1.4.1
RELENG_6_0
src/UPDATING 1.416.2.3.2.20
src/sys/conf/newvers.sh 1.69.2.8.2.16
src/crypto/openssh/auth.h 1.15.2.1.2.1
src/crypto/openssh/deattack.c 1.1.1.7.10.1
src/crypto/openssh/deattack.h 1.1.1.3.16.1
src/crypto/openssh/defines.h 1.1.1.9.2.1.2.1
src/crypto/openssh/log.c 1.1.1.13.4.1
src/crypto/openssh/log.h 1.6.4.1
src/crypto/openssh/packet.c 1.1.1.16.2.1.2.1
src/crypto/openssh/session.c 1.46.2.1.2.1
src/crypto/openssh/ssh_config 1.27.2.1.2.1
src/crypto/openssh/ssh_config.5 1.17.2.1.2.1
src/crypto/openssh/sshd.c 1.39.2.1.2.1
src/crypto/openssh/sshd_config 1.42.2.1.2.1
src/crypto/openssh/sshd_config.5 1.23.2.1.2.1
src/crypto/openssh/version.h 1.30.2.1.2.1
- -------------------------------------------------------------------------
VII. References
http://www.openssh.com/txt/release-4.4
http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2006-4924
http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2006-5051
The latest revision of this advisory is available at
http://security.FreeBSD.org/advisories/FreeBSD-SA-06:22.openssh.asc
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FreeBSD Security Advisories
2006-Sep-30 13:24 UTC
FreeBSD Security Advisory FreeBSD-SA-06:22.openssh
-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1
============================================================================FreeBSD-SA-06:22.openssh
Security Advisory
The FreeBSD Project
Topic: Multiple vulnerabilities in OpenSSH
Category: contrib
Module: openssh
Announced: 2006-09-30
Credits: Tavis Ormandy, Mark Dowd
Affects: All FreeBSD releases.
Corrected: 2006-09-30 19:50:57 UTC (RELENG_6, 6.2-PRERELEASE)
2006-09-30 19:51:56 UTC (RELENG_6_1, 6.1-RELEASE-p10)
2006-09-30 19:53:21 UTC (RELENG_6_0, 6.0-RELEASE-p15)
2006-09-30 19:54:03 UTC (RELENG_5, 5.5-STABLE)
2006-09-30 19:54:58 UTC (RELENG_5_5, 5.5-RELEASE-p8)
2006-09-30 19:55:52 UTC (RELENG_5_4, 5.4-RELEASE-p22)
2006-09-30 19:56:38 UTC (RELENG_5_3, 5.3-RELEASE-p37)
2006-09-30 19:57:15 UTC (RELENG_4, 4.11-STABLE)
2006-09-30 19:58:07 UTC (RELENG_4_11, 4.11-RELEASE-p25)
CVE Name: CVE-2006-4924, CVE-2006-5051
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
OpenSSH is an implementation of the SSH protocol suite, providing an
encrypted, authenticated transport for a variety of services,
including remote shell access.
II. Problem Description
The CRC compensation attack detector in the sshd(8) daemon, upon receipt
of duplicate blocks, uses CPU time cubic in the number of duplicate
blocks received. [CVE-2006-4924]
A race condition exists in a signal handler used by the sshd(8) daemon
to handle the LoginGraceTime option, which can potentially cause some
cleanup routines to be executed multiple times. [CVE-2006-5051]
III. Impact
An attacker sending specially crafted packets to sshd(8) can cause a
Denial of Service by using 100% of CPU time until a connection timeout
occurs. Since this attack can be performed over multiple connections
simultaneously, it is possible to cause up to MaxStartups (10 by default)
sshd processes to use all the CPU time they can obtain. [CVE-2006-4924]
The OpenSSH project believe that the race condition can lead to a Denial
of Service or potentially remote code execution, but the FreeBSD Security
Team has been unable to verify the exact impact. [CVE-2006-5051]
IV. Workaround
The attack against the CRC compensation attack detector can be avoided
by disabling SSH Protocol version 1 support in sshd_config(5).
There is no workaround for the second issue.
V. Solution
Perform one of the following:
1) Upgrade your vulnerable system to 4-STABLE, 5-STABLE, or 6-STABLE,
or to the RELENG_6_1, RELENG_6_0, RELENG_5_5, RELENG_5_4, RELENG_5_3,
or RELENG_4_11 security branch dated after the correction date.
2) To patch your present system:
The following patches have been verified to apply to FreeBSD 4.11, 5.3,
5.4, 5.5, 6.0, and 6.1 systems.
a) Download the relevant patch from the location below, and verify the
detached PGP signature using your PGP utility.
[FreeBSD 4.11]
# fetch http://security.FreeBSD.org/patches/SA-06:22/openssh4x.patch
# fetch http://security.FreeBSD.org/patches/SA-06:22/openssh4x.patch.asc
[FreeBSD 5.x]
# fetch http://security.FreeBSD.org/patches/SA-06:22/openssh5x.patch
# fetch http://security.FreeBSD.org/patches/SA-06:22/openssh5x.patch.asc
[FreeBSD 6.x]
# fetch http://security.FreeBSD.org/patches/SA-06:22/openssh6x.patch
# fetch http://security.FreeBSD.org/patches/SA-06:22/openssh6x.patch.asc
b) Execute the following commands as root:
# cd /usr/src
# patch < /path/to/patch
# cd /usr/src/secure/lib/libssh
# make obj && make depend && make && make install
# cd /usr/src/secure/usr.sbin/sshd
# make obj && make depend && make && make install
c) Restart the SSH daemon. On FreeBSD 5.x and 6.x, this can be done via
# /etc/rc.d/sshd restart
VI. Correction details
The following list contains the revision numbers of each file that was
corrected in FreeBSD.
Branch Revision
Path
- -------------------------------------------------------------------------
RELENG_4
src/crypto/openssh/deattack.c 1.1.1.1.2.6
src/crypto/openssh/deattack.h 1.1.1.1.2.3
src/crypto/openssh/defines.h 1.1.1.2.2.3
src/crypto/openssh/log.c 1.1.1.1.2.6
src/crypto/openssh/log.h 1.1.1.1.2.4
src/crypto/openssh/packet.c 1.1.1.1.2.7
src/crypto/openssh/ssh_config 1.2.2.10
src/crypto/openssh/ssh_config.5 1.4.2.6
src/crypto/openssh/sshd.c 1.6.2.12
src/crypto/openssh/sshd_config 1.4.2.14
src/crypto/openssh/sshd_config.5 1.5.2.8
src/crypto/openssh/version.h 1.1.1.1.2.14
RELENG_4_11
src/UPDATING 1.73.2.91.2.26
src/sys/conf/newvers.sh 1.44.2.39.2.29
src/crypto/openssh/deattack.c 1.1.1.1.2.5.6.1
src/crypto/openssh/deattack.h 1.1.1.1.2.2.10.1
src/crypto/openssh/defines.h 1.1.1.2.2.2.8.1
src/crypto/openssh/log.c 1.1.1.1.2.5.8.1
src/crypto/openssh/log.h 1.1.1.1.2.3.8.1
src/crypto/openssh/packet.c 1.1.1.1.2.6.8.1
src/crypto/openssh/ssh_config 1.2.2.9.6.1
src/crypto/openssh/ssh_config.5 1.4.2.5.6.1
src/crypto/openssh/sshd.c 1.6.2.11.8.1
src/crypto/openssh/sshd_config 1.4.2.13.6.1
src/crypto/openssh/sshd_config.5 1.5.2.7.4.1
src/crypto/openssh/version.h 1.1.1.1.2.13.6.1
RELENG_5
src/crypto/openssh/auth.h 1.13.2.1
src/crypto/openssh/deattack.c 1.1.1.7.2.1
src/crypto/openssh/deattack.h 1.1.1.3.8.1
src/crypto/openssh/defines.h 1.1.1.7.2.1
src/crypto/openssh/log.c 1.1.1.10.2.1
src/crypto/openssh/log.h 1.5.2.1
src/crypto/openssh/packet.c 1.1.1.14.2.1
src/crypto/openssh/session.c 1.44.2.1
src/crypto/openssh/ssh_config 1.25.2.2
src/crypto/openssh/ssh_config.5 1.15.2.2
src/crypto/openssh/sshd.c 1.37.2.1
src/crypto/openssh/sshd_config 1.40.2.2
src/crypto/openssh/sshd_config.5 1.21.2.2
src/crypto/openssh/version.h 1.27.2.2
RELENG_5_5
src/UPDATING 1.342.2.35.2.8
src/sys/conf/newvers.sh 1.62.2.21.2.10
src/crypto/openssh/auth.h 1.13.8.1
src/crypto/openssh/deattack.c 1.1.1.7.14.1
src/crypto/openssh/deattack.h 1.1.1.3.20.1
src/crypto/openssh/defines.h 1.1.1.7.8.1
src/crypto/openssh/log.c 1.1.1.10.8.1
src/crypto/openssh/log.h 1.5.8.1
src/crypto/openssh/packet.c 1.1.1.14.8.1
src/crypto/openssh/session.c 1.44.8.1
src/crypto/openssh/ssh_config 1.25.2.1.2.1
src/crypto/openssh/ssh_config.5 1.15.2.1.2.1
src/crypto/openssh/sshd.c 1.37.8.1
src/crypto/openssh/sshd_config 1.40.2.1.2.1
src/crypto/openssh/sshd_config.5 1.21.2.1.2.1
src/crypto/openssh/version.h 1.27.2.1.2.1
RELENG_5_4
src/UPDATING 1.342.2.24.2.31
src/sys/conf/newvers.sh 1.62.2.18.2.27
src/crypto/openssh/auth.h 1.13.6.1
src/crypto/openssh/deattack.c 1.1.1.7.6.1
src/crypto/openssh/deattack.h 1.1.1.3.12.1
src/crypto/openssh/defines.h 1.1.1.7.6.1
src/crypto/openssh/log.c 1.1.1.10.6.1
src/crypto/openssh/log.h 1.5.6.1
src/crypto/openssh/packet.c 1.1.1.14.6.1
src/crypto/openssh/session.c 1.44.6.1
src/crypto/openssh/ssh_config 1.25.6.2
src/crypto/openssh/ssh_config.5 1.15.6.2
src/crypto/openssh/sshd.c 1.37.6.1
src/crypto/openssh/sshd_config 1.40.6.2
src/crypto/openssh/sshd_config.5 1.21.6.2
src/crypto/openssh/version.h 1.27.6.2
RELENG_5_3
src/UPDATING 1.342.2.13.2.40
src/sys/conf/newvers.sh 1.62.2.15.2.42
src/crypto/openssh/auth.h 1.13.4.1
src/crypto/openssh/deattack.c 1.1.1.7.4.1
src/crypto/openssh/deattack.h 1.1.1.3.10.1
src/crypto/openssh/defines.h 1.1.1.7.4.1
src/crypto/openssh/log.c 1.1.1.10.4.1
src/crypto/openssh/log.h 1.5.4.1
src/crypto/openssh/packet.c 1.1.1.14.4.1
src/crypto/openssh/session.c 1.44.4.1
src/crypto/openssh/ssh_config 1.25.4.2
src/crypto/openssh/ssh_config.5 1.15.4.2
src/crypto/openssh/sshd.c 1.37.4.1
src/crypto/openssh/sshd_config 1.40.4.2
src/crypto/openssh/sshd_config.5 1.21.4.2
src/crypto/openssh/version.h 1.27.4.2
RELENG_6
src/crypto/openssh/auth.h 1.15.2.2
src/crypto/openssh/deattack.c 1.1.1.7.8.1
src/crypto/openssh/deattack.h 1.1.1.3.14.1
src/crypto/openssh/defines.h 1.1.1.9.2.2
src/crypto/openssh/log.c 1.1.1.13.2.1
src/crypto/openssh/log.h 1.6.2.1
src/crypto/openssh/packet.c 1.1.1.16.2.2
src/crypto/openssh/session.c 1.46.2.2
src/crypto/openssh/ssh_config 1.27.2.2
src/crypto/openssh/ssh_config.5 1.17.2.2
src/crypto/openssh/sshd.c 1.39.2.2
src/crypto/openssh/sshd_config 1.42.2.2
src/crypto/openssh/sshd_config.5 1.23.2.2
src/crypto/openssh/version.h 1.30.2.2
RELENG_6_1
src/UPDATING 1.416.2.22.2.12
src/sys/conf/newvers.sh 1.69.2.11.2.12
src/crypto/openssh/auth.h 1.15.2.1.4.1
src/crypto/openssh/deattack.c 1.1.1.7.12.1
src/crypto/openssh/deattack.h 1.1.1.3.18.1
src/crypto/openssh/defines.h 1.1.1.9.2.1.4.1
src/crypto/openssh/log.c 1.1.1.13.6.1
src/crypto/openssh/log.h 1.6.6.1
src/crypto/openssh/packet.c 1.1.1.16.2.1.4.1
src/crypto/openssh/session.c 1.46.2.1.4.1
src/crypto/openssh/ssh_config 1.27.2.1.4.1
src/crypto/openssh/ssh_config.5 1.17.2.1.4.1
src/crypto/openssh/sshd.c 1.39.2.1.4.1
src/crypto/openssh/sshd_config 1.42.2.1.4.1
src/crypto/openssh/sshd_config.5 1.23.2.1.4.1
src/crypto/openssh/version.h 1.30.2.1.4.1
RELENG_6_0
src/UPDATING 1.416.2.3.2.20
src/sys/conf/newvers.sh 1.69.2.8.2.16
src/crypto/openssh/auth.h 1.15.2.1.2.1
src/crypto/openssh/deattack.c 1.1.1.7.10.1
src/crypto/openssh/deattack.h 1.1.1.3.16.1
src/crypto/openssh/defines.h 1.1.1.9.2.1.2.1
src/crypto/openssh/log.c 1.1.1.13.4.1
src/crypto/openssh/log.h 1.6.4.1
src/crypto/openssh/packet.c 1.1.1.16.2.1.2.1
src/crypto/openssh/session.c 1.46.2.1.2.1
src/crypto/openssh/ssh_config 1.27.2.1.2.1
src/crypto/openssh/ssh_config.5 1.17.2.1.2.1
src/crypto/openssh/sshd.c 1.39.2.1.2.1
src/crypto/openssh/sshd_config 1.42.2.1.2.1
src/crypto/openssh/sshd_config.5 1.23.2.1.2.1
src/crypto/openssh/version.h 1.30.2.1.2.1
- -------------------------------------------------------------------------
VII. References
http://www.openssh.com/txt/release-4.4
http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2006-4924
http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2006-5051
The latest revision of this advisory is available at
http://security.FreeBSD.org/advisories/FreeBSD-SA-06:22.openssh.asc
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Pekka Savola
2006-Sep-30 18:13 UTC
[FreeBSD-Announce] FreeBSD Security Advisory FreeBSD-SA-06:22.openssh
On Sat, 30 Sep 2006, FreeBSD Security Advisories wrote:> III. Impact > > An attacker sending specially crafted packets to sshd(8) can cause a > Denial of Service by using 100% of CPU time until a connection timeout > occurs. Since this attack can be performed over multiple connections > simultaneously, it is possible to cause up to MaxStartups (10 by default) > sshd processes to use all the CPU time they can obtain. [CVE-2006-4924] > > The OpenSSH project believe that the race condition can lead to a Denial > of Service or potentially remote code execution, but the FreeBSD Security > Team has been unable to verify the exact impact. [CVE-2006-5051] > > IV. Workaround > > The attack against the CRC compensation attack detector can be avoided > by disabling SSH Protocol version 1 support in sshd_config(5). > > There is no workaround for the second issue.Doesn't TCP wrappers restriction mitigate or work around this issue or is it done too late ? -- Pekka Savola "You each name yourselves king, yet the Netcore Oy kingdom bleeds." Systems. Networks. Security. -- George R.R. Martin: A Clash of Kings
Mark Peek
2006-Oct-01 16:23 UTC
[FreeBSD-Announce] FreeBSD Security Advisory FreeBSD-SA-06:22.openssh
On 9/30/06 1:24 PM, FreeBSD Security Advisories wrote:> -----BEGIN PGP SIGNED MESSAGE----- > Hash: SHA1 > > ============================================================================> FreeBSD-SA-06:22.openssh Security Advisory > The FreeBSD Project > > Topic: Multiple vulnerabilities in OpenSSH > > Category: contrib > Module: openssh > Announced: 2006-09-30 > Credits: Tavis Ormandy, Mark Dowd > Affects: All FreeBSD releases. > Corrected: 2006-09-30 19:50:57 UTC (RELENG_6, 6.2-PRERELEASE) > 2006-09-30 19:51:56 UTC (RELENG_6_1, 6.1-RELEASE-p10) > 2006-09-30 19:53:21 UTC (RELENG_6_0, 6.0-RELEASE-p15) > 2006-09-30 19:54:03 UTC (RELENG_5, 5.5-STABLE) > 2006-09-30 19:54:58 UTC (RELENG_5_5, 5.5-RELEASE-p8) > 2006-09-30 19:55:52 UTC (RELENG_5_4, 5.4-RELEASE-p22) > 2006-09-30 19:56:38 UTC (RELENG_5_3, 5.3-RELEASE-p37) > 2006-09-30 19:57:15 UTC (RELENG_4, 4.11-STABLE) > 2006-09-30 19:58:07 UTC (RELENG_4_11, 4.11-RELEASE-p25) > CVE Name: CVE-2006-4924, CVE-2006-5051 > > 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 > > OpenSSH is an implementation of the SSH protocol suite, providing an > encrypted, authenticated transport for a variety of services, > including remote shell access.>snip< BTW, the patches for this advisory appear to also need a patch to add log.c into src/secure/usr.sbin/sshd/Makefile. Mark
Simon L. Nielsen
2006-Oct-02 12:11 UTC
[FreeBSD-Announce] FreeBSD Security Advisory FreeBSD-SA-06:22.openssh
On 2006.10.01 00:07:02 +0300, Pekka Savola wrote:> On Sat, 30 Sep 2006, FreeBSD Security Advisories wrote: > >III. Impact > > > >An attacker sending specially crafted packets to sshd(8) can cause a > >Denial of Service by using 100% of CPU time until a connection timeout > >occurs. Since this attack can be performed over multiple connections > >simultaneously, it is possible to cause up to MaxStartups (10 by default) > >sshd processes to use all the CPU time they can obtain. [CVE-2006-4924] > > > >The OpenSSH project believe that the race condition can lead to a Denial > >of Service or potentially remote code execution, but the FreeBSD Security > >Team has been unable to verify the exact impact. [CVE-2006-5051] > > > >IV. Workaround > > > >The attack against the CRC compensation attack detector can be avoided > >by disabling SSH Protocol version 1 support in sshd_config(5). > > > >There is no workaround for the second issue. > > Doesn't TCP wrappers restriction mitigate or work around this issue or > is it done too late ?I'm not sure since I have never really used TCP wrappers, but I would expect it to work. I generally use firewalls to restrict which IP addresses are allowed to access services when possible. -- Simon L. Nielsen
Simon L. Nielsen
2006-Oct-02 12:13 UTC
[FreeBSD-Announce] FreeBSD Security Advisory FreeBSD-SA-06:22.openssh
On 2006.10.01 15:10:50 -0700, Mark Peek wrote:> >Topic: Multiple vulnerabilities in OpenSSH > > BTW, the patches for this advisory appear to also need a patch to add log.c > into src/secure/usr.sbin/sshd/Makefile.Eh, why? log.c is built by libssh. -- Simon L. Nielsen
> The OpenSSH project believe that the race condition can lead to a Denial > of Service or potentially remote code execution^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Bullshit. Where did anyone say this? Why don't you put people in charge who can READ CODE, and SEE THAT THIS IS ABSOLUTE BULLSHIT.
Theo de Raadt wrote:>> The OpenSSH project believe that the race condition can lead to a Denial >> of Service or potentially remote code execution > ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ > Bullshit. Where did anyone say this?The OpenSSH 4.4 release announcement says that, actually: * Fix an unsafe signal hander reported by Mark Dowd. The signal handler was vulnerable to a race condition that could be exploited to perform a pre-authentication denial of service. On portable OpenSSH, this vulnerability could theoretically lead to ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ pre-authentication remote code execution if GSSAPI authentication ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ is enabled, but the likelihood of successful exploitation appears remote. Colin Percival
Mark Peek
2006-Oct-02 18:21 UTC
[FreeBSD-Announce] FreeBSD Security Advisory FreeBSD-SA-06:22.openssh
On 10/2/06 12:12 PM, Simon L. Nielsen wrote:> On 2006.10.01 15:10:50 -0700, Mark Peek wrote: >>> Topic: Multiple vulnerabilities in OpenSSH >> BTW, the patches for this advisory appear to also need a patch to add log.c >> into src/secure/usr.sbin/sshd/Makefile. > > Eh, why? log.c is built by libssh.Mea culpa! You are right, it was a problem with the way I was rebuilding it. Sorry for the noise on the list, I was erring on pinging you first since I thought it was a real issue. Mark
On Mon, Oct 02, 2006 at 02:25:05PM -0700, Colin Percival wrote:> Theo de Raadt wrote: > >> The OpenSSH project believe that the race condition can lead to a Denial > >> of Service or potentially remote code execution > > ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ > > Bullshit. Where did anyone say this? > > The OpenSSH 4.4 release announcement says that, actually: > > * Fix an unsafe signal hander reported by Mark Dowd. The signal > handler was vulnerable to a race condition that could be exploited > to perform a pre-authentication denial of service. On portable > OpenSSH, this vulnerability could theoretically lead to > ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ > pre-authentication remote code execution if GSSAPI authentication > ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ > is enabled, but the likelihood of successful exploitation appears > remote.Theo: Maybe you should put people in charge who can read their own release announcements before flaming a mailing list.
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