[SuSE][NetBSD] Fehler im OpenSSH Puffermanagement - SuSE-SA:2003:039 (rel.2) / NetBSD SA 2003-14

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[SuSE][NetBSD] Fehler im OpenSSH Puffermanagement - SuSE-SA:2003:039 (rel.2) / NetBSD SA 2003-14

DFN-Cert
19.09.2003

-----BEGIN PGP SIGNED MESSAGE-----

Liebe Kolleginnen und Kollegen,

Uns erreichten weitere Warnungen von SuSE und NetBSD ueber
Sicherheitsprobleme bei OpenSSH. Wir geben diese Informationen
unveraendert an Sie weiter.

CAN-2003-0693 - buffer_append_space() Bug

  Wird ein ungewoehnlich grosses Datenpaket von der OpenSSH
  verarbeitet, gibt der SSH Daemon faelschlicherweise global
  allozierte Puffer frei. Die daraus entstehenden Fehler in der
  Verwaltung des Heaps fuehren wahrscheinlich zu einem Absturz des SSH
  Daemons (Denial-of-Service).

  Es ist derzeit noch unklar, ob die Schwachstelle zur Ausfuehrung von
  Code ausgenutzt werden kann. Wenn ja, dann wuerde dieser Code mit
  Root-Rechten ausgefuehrt, es sei denn, Privilege Separation waere
  aktiviert (Option: UsePrivilegeSeparation yes in sshd_config), dann
  wird der Code mit der Kennung des nicht privilegierten Users
  (--with-privsep-user=user in der OpenSSH Compile Konfiguration)
  ausgefuehrt. Dies ist nicht in allen Installationen der Fall, da es
  manchmal Probleme bei der Authentifikation mit PAM-Modulen gibt.

  Weitere Informationen zur Schwachstelle finden Sie unter

        http://www.openssh.com/txt/buffer.adv
        http://www.kb.cert.org/vuls/id/333628

Betroffen sind alle OpenSSH Versionen vor 3.7.1, sowie alle SSH
Versionen, die davon abgeleitet sind. Welche Patches und Upgrades die
einzelnen Hersteller bereitstellen, entnehmen Sie bitte den
angefuegten Advisories.

(c) der deutschen Zusammenfassung bei DFN-CERT GmbH; die Verbreitung,
auch auszugsweise, ist nur unter Hinweis auf den Urheber, DFN-CERT GmbH,
und nur zu nicht kommerziellen Zwecken gestattet.

Mit freundlichen Gruessen,
                Klaus Moeller, DFN-CERT


- -----BEGIN PGP SIGNED MESSAGE-----

______________________________________________________________________________

                        SuSE Security Announcement

        Package:                openssh (second release)
        Announcement-ID:        SuSE-SA:2003:039
        Date:                   Thursday, Sep 18 2003 20:00 MEST
        Affected products:      7.2, 7.3, 8.0, 8.1, 8.2
                                SuSE Linux Database Server,
                                SuSE eMail Server III, 3.1
                                SuSE Linux Enterprise Server 7, 8
                                SuSE Linux Firewall on CD/Admin host
                                SuSE Linux Connectivity Server
                                SuSE Linux Office Server
                                SuSE Linux Standard Server 8
        Vulnerability Type:     potential remote privilege escalation
        Severity (1-10):        8
        SuSE default package:   yes
        Cross References:       http://www.openssh.com/txt/buffer.adv
                                CERTVU#333628 http://www.kb.cert.org/vuls/id/333628 
                                CVE CAN-2003-0693
                                CVE CAN-2003-0695
                                CVE CAN-2003-0682
    

    Content of this advisory:
        1) security vulnerability resolved: openssh
           problem description, discussion, solution and upgrade information
        2) pending vulnerabilities, solutions, workarounds:
            - mysql
        3) standard appendix (further information)

______________________________________________________________________________

1)  problem description, brief discussion, solution, upgrade information

    The openssh package is the most widely used implementation of the secure
    shell protocol family (ssh). It provides a set of network connectivity
    tools for remote (shell) login, designed to substitute the traditional
    BSD-style r-protocols (rsh, rlogin). openssh has various authentification
    mechanisms and many other features such as TCP connection and X11 display
    forwarding over the fully encrypted network connection as well as file
    transfer facilities.

    This is a new release of SuSE Security Announcement (openssh), 
    ID SuSE-SA:2003:038. A set of new bugs were addressed by the openssh 
    development team. These bugs are fixed in the new 3.7.1 upstream release 
    of the openssh package; we have added the necessary changes to our 
    packages preserving the package version to avoid the risk of incompatible 
    behaviour of the software.

    Specifics about the errors found:
    (Topic for SuSE Security Announcement SuSE-SA:2003:038:)
    A programming error has been found in code responsible for buffer
    management. If exploited by a (remote) attacker, the error may lead to
    unauthorized access to the system, allowing the execution of arbitrary
    commands. The error is known as the buffer_append_space()-bug and is 
    assigned the Common Vulnerabilities and Exposures (CVE) name CAN-2003-0693.
    The error was cause for the upstream release openssh-3.7.

    (Topic for SuSE Security Announcement SuSE-SA:2003:039 (this announcement):)
    Programming errors of a similar kind as described above have been found in 
    other portions of the code, with similar effects. These errors are known 
    as "buffer.c/channels.c bug", the CVE name for these errors is CAN-2003-0695.
    This set of errors was cause for the upstream release openssh-3.7.1.
    In addition to the fixes for the buffer.c/channels.c bugs we have added 
    some changes that have been assembled by Solar Designer during his review 
    of the source code. These fixes are considered a precautious measure and 
    are not believed to have a significant effect on the security of the 
    openssh code.

    At the time of writing this announcement, we believe that at least one set 
    of errors as described above is exploitable by a remote attacker. As a 
    reminder,  at the time of writing the SuSE Security Announcement 
    SuSE-SA:2003:038 it was unclear if the bug addressed with the announcement
    (buffer_append_space()-bug) is exploitable. An increasing amount of TCP 
    connection attempts to port 22 as observed in the internet during the 
    past days may indicate that there exists an exploit for the error in the 
    public.

    Please note that we have disabled the Privilege Separation feature in
    the ssh daemon (sshd) with this update. The PrivSep feature is designed
    to have parts of the ssh daemon's work running under lowered privileges,
    thereby limiting the effect of a possible vulnerability in the code. The
    PrivSep feature is turned on/off by the UsePrivilegeSeparation keyword
    in sshd's configuration file /etc/ssh/sshd_config. The feature is held
    responsible for malfunctions in PAM (Pluggable Authentification Modules).
    The update mechanism will not overwrite configuration files that have
    been altered after the package installation.



    SPECIAL INSTALL INSTRUCTIONS:
    ==============================
    After the update has been successfully applied, the ssh daemon (sshd)
    must be restarted for update package to become effective. To restart the
    ssh daemon after the update, please run the following command as root:

      rcsshd restart


    Please download the update package for your distribution and verify its
    integrity by the methods listed in section 3) of this announcement.
    Then, install the package using the command "rpm -Fhv file.rpm" to apply
    the update.
    Our maintenance customers are being notified individually. The packages
    are being offered to install from the maintenance web.





    Intel i386 Platform:

    SuSE-8.2:
    ftp://ftp.suse.com/pub/suse/i386/update/8.2/rpm/i586/openssh-3.5p1-107.i586.rpm
      e030b0803481d0f29f576e3b4726284f
    patch rpm(s):
    ftp://ftp.suse.com/pub/suse/i386/update/8.2/rpm/i586/openssh-3.5p1-107.i586.patch.rpm
      d022894363b99e6bd03e9b2109c2244c
    source rpm(s):
    ftp://ftp.suse.com/pub/suse/i386/update/8.2/rpm/src/openssh-3.5p1-107.src.rpm
      3f7f5ed43c7d795c63fe06148874944a

    SuSE-8.1:
    ftp://ftp.suse.com/pub/suse/i386/update/8.1/rpm/i586/openssh-3.4p1-215.i586.rpm
      91cdd33a4149756b8f6371aa3177a5f4
    patch rpm(s):
    ftp://ftp.suse.com/pub/suse/i386/update/8.1/rpm/i586/openssh-3.4p1-215.i586.patch.rpm
      3b7c44819c8fed5e33514481d99d4ab7
    source rpm(s):
    ftp://ftp.suse.com/pub/suse/i386/update/8.1/rpm/src/openssh-3.4p1-215.src.rpm
      6c3694fc75bcf185035547b85abbc491

    SuSE-8.0:
    ftp://ftp.suse.com/pub/suse/i386/update/8.0/sec1/openssh-3.4p1-215.i386.rpm
      c61781b97767188cc3a39795535307ff
    patch rpm(s):
    ftp://ftp.suse.com/pub/suse/i386/update/8.0/sec1/openssh-3.4p1-215.i386.patch.rpm
      c222aef79a8fef6d44d8d61fc075efc5
    source rpm(s):
    ftp://ftp.suse.com/pub/suse/i386/update/8.0/zq1/openssh-3.4p1-215.src.rpm
      bc327a4150058c9d1216cb96712973a5

    SuSE-7.3:
    ftp://ftp.suse.com/pub/suse/i386/update/7.3/sec1/openssh-2.9.9p2-156.i386.rpm
      c9928c04b03cb292aa96ad6890a5ee38
    source rpm(s):
    ftp://ftp.suse.com/pub/suse/i386/update/7.3/zq1/openssh-2.9.9p2-156.src.rpm
      28aa82be9233e3ba93b94eb138c9ea04

    SuSE-7.2:
    ftp://ftp.suse.com/pub/suse/i386/update/7.2/sec1/openssh-2.9.9p2-156.i386.rpm
      b369724a788a2c6bd70a448a49530f69
    source rpm(s):
    ftp://ftp.suse.com/pub/suse/i386/update/7.2/zq1/openssh-2.9.9p2-156.src.rpm
      98b8b7281fe04aab8c8838adcf195697




    Sparc Platform:

    SuSE-7.3:
    ftp://ftp.suse.com/pub/suse/sparc/update/7.3/sec1/openssh-2.9.9p2-53.sparc.rpm
      97cb0218e9354b8cc062e44a0d6fb19f
    source rpm(s):
    ftp://ftp.suse.com/pub/suse/sparc/update/7.3/zq1/openssh-2.9.9p2-53.src.rpm
      8cddb96e633864469d7ba08d3cf7436a



    PPC Power PC Platform:

    SuSE-7.3:
    ftp://ftp.suse.com/pub/suse/ppc/update/7.3/sec1/openssh-2.9.9p2-109.ppc.rpm
      37b1e82a3971f5c4c427ce37227b11e0
    source rpm(s):
    ftp://ftp.suse.com/pub/suse/ppc/update/7.3/zq1/openssh-2.9.9p2-109.src.rpm
      7a19424887772b86d14bacbf5add9628


______________________________________________________________________________

2)  Pending vulnerabilities in SuSE Distributions and Workarounds:

  - A buffer overflow vulnerability has been found in the mysql package,
    an Open Source relational database system. The error may allow a remote
    attacker to execute arbitrary code with the privileges of the database
    process.
    We are in the process of building and testing the update packages and
    will release them with a SuSE Security Announcement as soon as possible.

______________________________________________________________________________

3)  standard appendix: authenticity verification, additional information

  - Package authenticity verification:

    SuSE update packages are available on many mirror ftp servers all over 
    the world. While this service is being considered valuable and important
    to the free and open source software community, many users wish to be 
    sure about the origin of the package and its content before installing
    the package. There are two verification methods that can be used 
    independently from each other to prove the authenticity of a downloaded
    file or rpm package:
    1) md5sums as provided in the (cryptographically signed) announcement.
    2) using the internal gpg signatures of the rpm package.

    1) execute the command 
        md5sum <name-of-the-file.rpm>
       after you downloaded the file from a SuSE ftp server or its mirrors.
       Then, compare the resulting md5sum with the one that is listed in the
       announcement. Since the announcement containing the checksums is 
       cryptographically signed (usually using the key security@suse.de), 
       the checksums show proof of the authenticity of the package.
       We disrecommend to subscribe to security lists which cause the 
       email message containing the announcement to be modified so that
       the signature does not match after transport through the mailing 
       list software.
       Downsides: You must be able to verify the authenticity of the
       announcement in the first place. If RPM packages are being rebuilt
       and a new version of a package is published on the ftp server, all 
       md5 sums for the files are useless.

    2) rpm package signatures provide an easy way to verify the authenticity
       of an rpm package. Use the command
        rpm -v --checksig <file.rpm>
       to verify the signature of the package, where <file.rpm> is the
       filename of the rpm package that you have downloaded. Of course, 
       package authenticity verification can only target an un-installed rpm
       package file.
       Prerequisites:
        a) gpg is installed
        b) The package is signed using a certain key. The public part of this
           key must be installed by the gpg program in the directory 
           ~/.gnupg/ under the user's home directory who performs the
           signature verification (usually root). You can import the key
           that is used by SuSE in rpm packages for SuSE Linux by saving
           this announcement to a file ("announcement.txt") and
           running the command (do "su -" to be root):
            gpg --batch; gpg < announcement.txt | gpg --import
           SuSE Linux distributions version 7.1 and thereafter install the
           key "build@suse.de" upon installation or upgrade, provided that
           the package gpg is installed. The file containing the public key
           is placed at the top-level directory of the first CD (pubring.gpg)
           and at ftp://ftp.suse.com/pub/suse/pubring.gpg-build.suse.de .


  - SuSE runs two security mailing lists to which any interested party may
    subscribe:

    suse-security@suse.com
        -   general/linux/SuSE security discussion. 
            All SuSE security announcements are sent to this list.
            To subscribe, send an email to 
                <suse-security-subscribe@suse.com>.

    suse-security-announce@suse.com
        -   SuSE's announce-only mailing list.
            Only SuSE's security announcements are sent to this list.
            To subscribe, send an email to
                <suse-security-announce-subscribe@suse.com>.

    For general information or the frequently asked questions (faq) 
    send mail to:
        <suse-security-info@suse.com> or
        <suse-security-faq@suse.com> respectively.

    =====================================================================
    SuSE's security contact is <security@suse.com> or <security@suse.de>.
    The <security@suse.de> public key is listed below.
    =====================================================================
______________________________________________________________________________

    The information in this advisory may be distributed or reproduced,
    provided that the advisory is not modified in any way. In particular,
    it is desired that the clear-text signature shows proof of the
    authenticity of the text.
    SuSE Linux AG makes no warranties of any kind whatsoever with respect
    to the information contained in this security advisory.

Type Bits/KeyID    Date       User ID
pub  2048R/3D25D3D9 1999-03-06 SuSE Security Team <security@suse.de>
pub  1024D/9C800ACA 2000-10-19 SuSE Package Signing Key <build@suse.de>

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Roman Drahtmüller,
SuSE Security.
- - -- 
 -                                                                      -
| Roman Drahtmüller      <draht@suse.de> // "You don't need eyes to see, |
  SuSE Linux AG - Security       Phone: //             you need vision!"
| Nürnberg, Germany     +49-911-740530 //           Maxi Jazz, Faithless |
 -                                                                      -
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====================================================================

- -----BEGIN PGP SIGNED MESSAGE-----


   NetBSD Security Advisory 2003-014
   =================================

Topic:  Insufficient argument checking in sysctl(2)

Version: NetBSD-current: source prior to August 25, 2003
  NetBSD 1.6.1: affected
  NetBSD 1.6: affected
  NetBSD-1.5.3: affected
  NetBSD-1.5.2: affected
  NetBSD-1.5.1: affected
  NetBSD-1.5: affected

Severity: local DOS, read protected kernel memory

Fixed:  NetBSD-current:  August 25, 2003
  NetBSD-1.6 branch: August 28, 2003 (1.6.2 will include the fix)
  NetBSD-1.5 branch: August 28, 2003


Abstract
========

Three unrelated problems with inappropriate argument handling were
found in the kernel sysctl(2) code, which could be exploited by
malicious local user:

  Some sysctl nodes could cause the kernel to dereference a NULL
  pointer, resulting in a panic.

  Passing the process id of a zombie process could cause the kernel to
  dereference invalid process data, and panic.

  Other sysctl nodes had an insufficient range check, which could be
  abused to read arbitrary locations in kernel memory space.


Technical Details
=================

There are three unrelated problems, found during an effort to rewrite
the present sysctl(2) infrastructure.

1) A pointer variable was used both for pointing user-level address
   (sysctl(2) argument) and kernel address, and there was a chance for
   a local user to set NULL pointer to the variable.

2) The proc.* sysctl tree could be invoked on a zombie process, but
   made assumptions that the processes were in a valid state, and so
   could attempt to reference process information that is invalid or
   non-existent for zombies.  This is no longer possible.

3) Under the proc.curproc.rlimit subtree are a number of nodes
   representing the process resource limits, soft and hard. The sysctl
   helper used to manipulate these values had an insufficient range
   check, and could be used to read values outside of the working copy
   of the rlimit structure.  Writes were checked more thoroughly, and
   could not abuse this problem.


Solutions and Workarounds
=========================

To correct this problem, upgrade of the kernel (and reboot) is
required.  There is no practical work-around for systems running the
vulnerable code in the kernel.

The fixes for all of these issues are contained in the one file,
sys/kern/kern_sysctl.c. The following table lists the fixed revisions
and dates of this file for each branch:

  CVS branch     revision     date
  -------------  -----------  ----------------
  HEAD           1.143        2003/08/24
  netbsd-1-6     1.108.4.3    2003/08/27
  netbsd-1-5     1.73.2.7     2003/08/27

The following instructions describe how to upgrade your kernel
binaries by updating your source tree and rebuilding and installing a
new version of the kernel. In these instructions, replace: 

  BRANCH   with the appropriate CVS branch (from the above table)
  ARCH     with your architecture (from uname -m), and
  KERNCONF with the name of your kernel configuration file.

To update from CVS, re-build, and re-install the kernel:

 # cd src
 # cvs update -d -P -r BRANCH sys/kern/kern_sysctl.c
 # cd sys/ARCH/conf
 # config KERNCONF
 # cd ../compile/KERNCONF
 # make depend;make
 # mv /netbsd /netbsd.old
 # cp netbsd /
 # reboot


Thanks To
=========

Andrew Brown


Revision History
================

 2003-09-17 Initial release


More Information
================

Advisories may be updated as new information becomes available.
The most recent version of this advisory (PGP signed) can be found at 
  ftp://ftp.NetBSD.org/pub/NetBSD/security/advisories/NetBSD-SA2003-014.txt.asc

Information about NetBSD and NetBSD security can be found at
http://www.NetBSD.org/ and http://www.NetBSD.org/Security/.


Copyright 2003, The NetBSD Foundation, Inc.  All Rights Reserved.
Redistribution permitted only in full, unmodified form.

$NetBSD: NetBSD-SA2003-014.txt,v 1.12 2003/09/17 02:49:00 david Exp $

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- -- 
Klaus Moeller          |                      mailto:moeller@cert.dfn.de
DFN-CERT GmbH          |            http://www.cert.dfn.de/team/moeller/
Heidenkampsweg 41      |                        Phone: +49(40)808077-555
D-20097 Hamburg        |                          FAX: +49(40)808077-556
Germany                |              PGP-Key: RSA 2048 Bit ID: 0BB7C8F9

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