[ GLSA 200410-29 ] PuTTY: Pre-authentication buffer overflow

From: Sune Kloppenborg Jeppesen (jaervosz_at_gentoo.org)
Date: 10/27/04

  • Next message: Sune Kloppenborg Jeppesen: "[Full-Disclosure] [ GLSA 200410-29 ] PuTTY: Pre-authentication buffer overflow" 
    To: gentoo-announce@gentoo.org
Date: Wed, 27 Oct 2004 23:47:43 +0200

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    Gentoo Linux Security Advisory GLSA 200410-29
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                                                http://security.gentoo.org/
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      Severity: Normal
         Title: PuTTY: Pre-authentication buffer overflow
          Date: October 27, 2004
          Bugs: #69123
            ID: 200410-29

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    Synopsis
    ========

    PuTTY contains a vulnerability allowing an SSH server to execute
    arbitrary code on the connecting client.

    Background
    ==========

    PuTTY is a free implementation of Telnet and SSH for Win32 and Unix
    platforms, along with an xterm terminal emulator.

    Affected packages
    =================

        -------------------------------------------------------------------
         Package / Vulnerable / Unaffected
        -------------------------------------------------------------------
      1 net-misc/putty <= 0.55 >= 0.56

    Description
    ===========

    PuTTY fails to do proper bounds checking on SSH2_MSG_DEBUG packets. The
    "stringlen" parameter value is incorrectly checked due to signedness
    issues. Note that this vulnerability is similar to the one described in
    GLSA 200408-04 but not the same.

    Impact
    ======

    When PuTTY connects to a server using the SSH2 protocol, an attacker
    may be able to send specially crafted packets to the client, resulting
    in the execution of arbitrary code with the permissions of the user
    running PuTTY. Note that this is possible during the authentication
    process but before host key verification.

    Workaround
    ==========

    There is no known workaround at this time.

    Resolution
    ==========

    All PuTTY users should upgrade to the latest version:

        # emerge --sync
        # emerge --ask --oneshot --verbose ">=net-misc/putty-0.56"

    References
    ==========

      [ 1 ] iDEFENSE Security Advisory 10.27.04
            http://www.idefense.com/application/poi/display?id=155
      [ 2 ] PuTTY ChangeLog
            http://www.chiark.greenend.org.uk/~sgtatham/putty/changes.html

    Availability
    ============

    This GLSA and any updates to it are available for viewing at
    the Gentoo Security Website:

      http://security.gentoo.org/glsa/glsa-200410-29.xml

    Concerns?
    =========

    Security is a primary focus of Gentoo Linux and ensuring the
    confidentiality and security of our users machines is of utmost
    importance to us. Any security concerns should be addressed to
    security@gentoo.org or alternatively, you may file a bug at
    http://bugs.gentoo.org.

    License
    =======

    Copyright 2004 Gentoo Foundation, Inc; referenced text
    belongs to its owner(s).

    The contents of this document are licensed under the
    Creative Commons - Attribution / Share Alike license.

    http://creativecommons.org/licenses/by-sa/1.0

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