iDEFENSE Security Advisory 05.25.05: GNU Mailutils 0.6 imap4d fetch_io Heap overflow Vulnerability

From: iDEFENSE Labs (labs-no-reply_at_idefense.com)
Date: 05/25/05

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    Date: Wed, 25 May 2005 13:25:31 -0400
To: <bugtraq@securityfocus.com>, <vulnwatch@vulnwatch.org>, <full-disclosure@lists.grok.org.uk>

    GNU Mailutils 0.6 imap4d fetch_io Heap overflow Vulnerability

    iDEFENSE Security Advisory 05.25.05
    http://www.idefense.com/application/poi/display?type=vulnerabilities
    May 25, 2005

    I. BACKGROUND

    The GNU mailutils package is a collection of mail-related
    utilities, including local and remote mailbox access services.
    More information is available at the following site:

        http://www.gnu.org/software/mailutils/mailutils.html

    II. DESCRIPTION

    Remote exploitation of an integer overflow in the fetch_io
    function of the imap4d server from the GNU Project's Mailutils
    package error may allow an authenticated remote attacker to
    execute arbitrary code.

    The imap4d server allows remote users to retrieve their email
    via the Internet Message Access Protocol, version 4rev1 as
    specified in RFC3501. This is a client/server protocol supported
    by a large number of email clients on multiple platforms.

    The vulnerability specifically exists in the handling of partial
    message requests. By supplying a value for the 'END' parameter
    equal to 2 less than the largest value an integer on the
    affected system can hold, it is possible to cause the server to
    allocate a much smaller chunk of memory. An overflow can occur
    when this memory chunk is referenced.

    III. ANALYSIS

    Successful exploitation of this vulnerability could allow a
    remote authenticated used execute arbitrary commands in the
    context of the 'daemon' user. As the service is forked from a
    parent process, it would be possible for a remote attacker to
    attempt to exploit this vulnerability multiple times, although
    each failed attempt which caused a crash would be logged.

    IV. DETECTION

    iDEFENSE Labs has verified the existance of this vulnerability
    in versions 0.5 and 0.6 of the GNU Mailutils package. It is
    suspected that any previous versions which contain the imap4d
    server are also affected.

    V. WORKAROUND

    iDEFENSE is currently unaware of any effective workarounds for
    this issue. Access to the affected host should be filtered at
    the network boundary if global accessibility is not required.
    Restricting access to only trusted hosts and networks may reduce
    the likelihood of exploitation.

    VI. VENDOR RESPONSE

    This vulnerability has been fixed in GNU mailutils 0.6.90 which is
    available for download at:

       ftp://alpha.gnu.org/gnu/mailutils/

    VII. CVE INFORMATION

    The Common Vulnerabilities and Exposures (CVE) project has assigned the
    name CAN-2005-1521 to this issue. This is a candidate for inclusion in
    the CVE list (http://cve.mitre.org), which standardizes names for
    security problems.

    VIII. DISCLOSURE TIMELINE

    05/12/2005 Initial vendor notification
    05/12/2005 Initial vendor response
    05/25/2005 Public disclosure

    IX. CREDIT

    infamous41md@hotpop.com is credited with the discovery of this
    vulnerability.

    Get paid for vulnerability research
    http://www.idefense.com/poi/teams/vcp.jsp

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    http://labs.idefense.com

    X. LEGAL NOTICES

    Copyright (c) 2005 iDEFENSE, Inc.

    Permission is granted for the redistribution of this alert
    electronically. It may not be edited in any way without the express
    written consent of iDEFENSE. If you wish to reprint the whole or any
    part of this alert in any other medium other than electronically, please
    email customerservice@idefense.com for permission.

    Disclaimer: The information in the advisory is believed to be accurate
    at the time of publishing based on currently available information. Use
    of the information constitutes acceptance for use in an AS IS condition.
    There are no warranties with regard to this information. Neither the
    author nor the publisher accepts any liability for any direct, indirect,
    or consequential loss or damage arising from use of, or reliance on,
    this information.

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