[ GLSA 200405-19 ] Opera telnet URI handler file creation/truncation vulnerability

From: Kurt Lieber (klieber_at_gentoo.org)
Date: 05/25/04

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    Date: Tue, 25 May 2004 11:59:29 -0400
To: gentoo-announce@lists.gentoo.org

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    Gentoo Linux Security Advisory GLSA 200405-19
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                                                http://security.gentoo.org/
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      Severity: Normal
         Title: Opera telnet URI handler file creation/truncation
                vulnerability
          Date: May 25, 2004
          Bugs: #50857
            ID: 200405-19

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    Synopsis
    ========

    A vulnerability exists in Opera's telnet URI handler that may allow a
    remote attacker to overwrite arbitrary files.

    Background
    ==========

    Opera is a multi-platform web browser.

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

        -------------------------------------------------------------------
         Package / Vulnerable / Unaffected
        -------------------------------------------------------------------
      1 net-www/opera < 7.50_beta1 >= 7.50_beta1

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

    The telnet URI handler in Opera does not check for leading '-'
    characters in the host name. Consequently, a maliciously-crafted
    telnet:// link may be able to pass options to the telnet program
    itself. One example would be the following:

    telnet://-nMyFile

    If MyFile exists in the user's home directory and the user clicking on
    the link has write permissions to it, the contents of the file will be
    overwritten with the output of the telnet trace information. If MyFile
    does not exist, the file will be created in the user's home directory.

    Impact
    ======

    This exploit has two possible impacts. First, it may create new files
    in the user's home directory. Second, and far more serious, it may
    overwrite existing files that the user has write permissions to. An
    attacker with some knowledge of a user's home directory might be able
    to destroy important files stored within.

    Workaround
    ==========

    Disable the telnet URI handler from within Opera.

    Resolution
    ==========

    All Opera users are encouraged to upgrade to the latest version of the
    program:

        # emerge sync

        # emerge -pv ">=net-www/opera-7.50_beta1"
        # emerge ">=net-www/opera-7.50_beta1"

    References
    ==========

      [ 1 ] iDEFENSE Security Advisory 05.12.04
            http://www.idefense.com/application/poi/display?id=104&type=vulnerabilities&flashstatus=true

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

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

         http://security.gentoo.org/glsa/glsa-200405-19.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 Technologies, 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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