AusCERT - ESB-2013.0516 - [AIX] OpenSSH: Denial of service

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ESB-2013.0516 - [AIX] OpenSSH: Denial of service - Remote/unauthenticated
Date: 10 April 2013
References: ESB-2013.0634

Click here for printable version
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===========================================================================
             AUSCERT External Security Bulletin Redistribution

                               ESB-2013.0516
                         AIX OpenSSH Vulnerability
                               10 April 2013

===========================================================================

        AusCERT Security Bulletin Summary
        ---------------------------------

Product:           OpenSSH
Publisher:         IBM
Operating System:  AIX
Impact/Access:     Denial of Service -- Remote/Unauthenticated
Resolution:        Patch/Upgrade
CVE Names:         CVE-2010-5107  

Original Bulletin: 
   http://aix.software.ibm.com/aix/efixes/security/openssh_advisory2.asc

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IBM SECURITY ADVISORY

First Issued: Mon Apr 8 15:19:58 CDT 2013

The most recent version of this document is available here:

http://aix.software.ibm.com/aix/efixes/security/openssh_advisory2.asc
or
ftp://aix.software.ibm.com/aix/efixes/security/openssh_advisory2.asc
===============================================================================
                           VULNERABILITY SUMMARY

VULNERABILITY:   AIX OpenSSH Vulnerability

PLATFORMS:       AIX 5.3, 6.1 and 7.1

SOLUTION:        Apply the fix as described below.

THREAT:          See below

CVE Numbers:     CVE-2010-5107

Reboot required?    NO
Workarounds?        NO
Protected by FPM?   NO
Protected by SED?   NO
===============================================================================
                           DETAILED INFORMATION

I. DESCRIPTION (From cve.mitre.org)
   
    CVE-2010-5107

    The default configuration of OpenSSH through 6.1 enforces a fixed time 
    limit between establishing a TCP connection and completing a login, which 
    makes it easier for remote attackers to cause a denial of service  
    (connection-slot exhaustion) by periodically making many new TCP 
    connections.

    http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2010-5107

II. CVSS

    CVSS Base Score: 5.0
    CVSS Temporal Score: See http://xforce.iss.net/xforce/xfdb/82781 for the
    current score
    CVSS Environmental Score*: Undefined
    CVSS String: (AV:N/AC:L/Au:N/C:N/I:N/A:P)

III. PLATFORM VULNERABILITY ASSESSMENT

    To determine if your system is vulnerable, execute the following
    command:

    lslpp -L openssh.base.server

    The following fileset levels are vulnerable:

    AIX: 7.1, 6.1, 5.3: all versions less than or equal to 6.1.6101 
    VIOS: 7.1, 6.1, 5.3: all versions less than or equal to 6.1.6101 

IV. FIXES

    A fix is available, and it can be downloaded from:

    https://www14.software.ibm.com/webapp/iwm/web/preLogin.do?source=aixbp

    To extract the fixes from the tar file:

    zcat OpenSSH_6.0.0.6102.tar.Z | tar xvf -

    IMPORTANT: If possible, it is recommended that a mksysb backup
    of the system be created.  Verify it is both bootable and
    readable before proceeding.

    To preview the fix installation:

    installp -apYd . OpenSSH_6.0.0.6102

    To install the fix package:

    installp -aXYd . OpenSSH_6.0.0.6102

V. WORKAROUNDS

    There are no workarounds.

VI. CONTACT INFORMATION

    If you would like to receive AIX Security Advisories via email,
    please visit:

        http://www.ibm.com/systems/support

    and click on the "My notifications" link.

    To view previously issued advisories, please visit:

        http://www14.software.ibm.com/webapp/set2/subscriptions/onvdq
 
    Comments regarding the content of this announcement can be
    directed to:

        security-alert@austin.ibm.com

    To obtain the PGP public key that can be used to communicate
    securely with the AIX Security Team you can either:

        A. Send an email with "get key" in the subject line to:

            security-alert@austin.ibm.com

        B. Download the key from our web page:

  http://www.ibm.com/systems/resources/systems_p_os_aix_security_pgpkey.txt

        C. Download the key from a PGP Public Key Server. The key ID is:

	    0x28BFAA12

    Please contact your local IBM AIX support center for any
    assistance.

    eServer is a trademark of International Business Machines
    Corporation.  IBM, AIX and pSeries are registered trademarks of
    International Business Machines Corporation.  All other trademarks
    are property of their respective holders.


VII. REFERENCES:

    Complete CVSS Guide: http://www.first.org/cvss/cvss-guide.html
    On-line Calculator V2: http://nvd.nist.gov/cvss.cfm?calculator&adv&version=2
    X-Force Vulnerability Database: http://xforce.iss.net/xforce/xfdb/82781 
    CVE-2013-0169: http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2010-5107

    *The CVSS Environment Score is customer environment specific and will
    ultimately impact the Overall CVSS Score. Customers can evaluate the
    impact of this vulnerability in their environments by accessing the links
    in the Reference section of this Flash.

    Note: According to the Forum of Incident Response and Security Teams
    (FIRST), the Common Vulnerability Scoring System (CVSS) is an "industry
    open standard designed to convey vulnerability severity and help to
    determine urgency and priority of response." IBM PROVIDES THE CVSS SCORES
    "AS IS" WITHOUT WARRANTY OF ANY KIND, INCLUDING THE IMPLIED WARRANTIES OF
    MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. CUSTOMERS ARE
    RESPONSIBLE FOR ASSESSING THE IMPACT OF ANY ACTUAL OR POTENTIAL SECURITY
    VULNERABILITY.
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===========================================================================
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The University of Queensland
Brisbane
Qld 4072

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