Neohapsis is currently accepting applications for employment. For more information, please visit our website www.neohapsis.com or email hr@neohapsis.com
From: FreeBSD Security Advisories (security-advisoriesFreeBSD.org)
Date: Tue Jan 30 2001 - 03:26:13 CST

  • Messages sorted by: [ date ] [ thread ] [ subject ] [ author ]


    FreeBSD-SA-01:17 Security Advisory
                                                                    FreeBSD, Inc.

    Topic: exmh symlink vulnerability

    Category: ports
    Module: exmh2
    Announced: 2001-01-29
    Credits: Stanley G. Bubrouski <stanCCS.NEU.EDU>
    Affects: Ports collection prior to the correction date.
    Corrected: 2001-01-22
    Vendor status: Updated version released
    FreeBSD only: No

    I. Background

    exmh is a tcl/tk based interface to the mh mail user agent.

    II. Problem Description

    The exmh2 port, versions prior to 2.3.1, contains a local
    vulnerability: at startup, if exmh detects a problem in its code or
    configuration an error dialog appears giving the user an option to
    fill in a bug report and email it to the maintainer. If the user
    agrees to mail the maintainer a file named /tmp/exmhErrorMsg is
    created. If the file exists and is a symlink, it will follow the
    link, allowing local files writable by the user to be overwritten.

    The exmh2 port is not installed by default, nor is it "part of
    FreeBSD" as such: it is part of the FreeBSD ports collection, which
    contains over 4500 third-party applications in a ready-to-install
    format. The ports collections shipped with FreeBSD 3.5.1 and 4.2
    contain this problem since it was discovered after the releases.

    FreeBSD makes no claim about the security of these third-party
    applications, although an effort is underway to provide a security
    audit of the most security-critical ports.

    III. Impact

    Malicious local users may cause arbitrary files writable by the user
    running exmh to be overwritten, in certain restricted situations.

    If you have not chosen to install the exmh2 port/package, then your
    system is not vulnerable to this problem.

    IV. Workaround

    Deinstall the exmh2 port/package, if you have installed it.

    V. Solution

    One of the following:

    1) Upgrade your entire ports collection and rebuild the exmh2 port.

    2) Deinstall the old package and install a new package dated after the
    correction date, obtained from:


    Packages are not automatically generated for the alpha architecture at
    this time due to lack of build resources.

    3) download a new port skeleton for the exmh2 port from:


    and use it to rebuild the port.

    4) Use the portcheckout utility to automate option (3) above. The
    portcheckout port is available in /usr/ports/devel/portcheckout or the
    package can be obtained from:


    Version: GnuPG v1.0.4 (FreeBSD)
    Comment: For info see http://www.gnupg.org

    -----END PGP SIGNATURE-----

    To Unsubscribe: send mail to majordomoFreeBSD.org
    with "unsubscribe freebsd-security" in the body of the message