[ GLSA 200511-17 ] FUSE: mtab corruption through fusermount

From: Thierry Carrez (koon_at_gentoo.org)
Date: 11/22/05

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    Gentoo Linux Security Advisory GLSA 200511-17
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                                                http://security.gentoo.org/
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      Severity: Normal
         Title: FUSE: mtab corruption through fusermount
          Date: November 22, 2005
          Bugs: #112902
            ID: 200511-17

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    Synopsis
    ========

    The fusermount utility from FUSE can be abused to corrupt the /etc/mtab
    file contents, potentially allowing a local attacker to set
    unauthorized mount options.

    Background
    ==========

    FUSE (Filesystem in Userspace) allows implementation of a fully
    functional filesystem in a userspace program. The fusermount utility is
    used to mount/unmount FUSE file systems.

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

        -------------------------------------------------------------------
         Package / Vulnerable / Unaffected
        -------------------------------------------------------------------
      1 sys-fs/fuse < 2.4.1-r1 >= 2.4.1-r1

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

    Thomas Biege discovered that fusermount fails to securely handle
    special characters specified in mount points.

    Impact
    ======

    A local attacker could corrupt the contents of the /etc/mtab file by
    mounting over a maliciously-named directory using fusermount,
    potentially allowing the attacker to set unauthorized mount options.
    This is possible only if fusermount is installed setuid root, which is
    the default in Gentoo.

    Workaround
    ==========

    There is no known workaround at this time.

    Resolution
    ==========

    All FUSE users should upgrade to the latest version:

        # emerge --sync
        # emerge --ask --oneshot --verbose ">=sys-fs/fuse-2.4.1-r1"

    References
    ==========

      [ 1 ] CVE-2005-3531
            http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2005-3531

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

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

      http://security.gentoo.org/glsa/glsa-200511-17.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 2005 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/2.0

    
    



  • Next message: Martin Schulze: "[SECURITY] [DSA 900-3] New fetchmail-ssl packages fix potential information leak"

    Relevant Pages

    • [Full-disclosure] [ GLSA 200511-17 ] FUSE: mtab corruption through fusermount
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