94 lines
3.3 KiB
XML
94 lines
3.3 KiB
XML
<?xml version="1.0" encoding="utf-8"?>
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<?xml-stylesheet href="/xsl/glsa.xsl" type="text/xsl"?>
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<?xml-stylesheet href="/xsl/guide.xsl" type="text/xsl"?>
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<!DOCTYPE glsa SYSTEM "http://www.gentoo.org/dtd/glsa.dtd">
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<glsa id="200402-02">
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<title>XFree86 Font Information File Buffer Overflow</title>
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<synopsis>
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Exploitation of a buffer overflow in the XFree86 Project Inc.'s XFree86 X
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Window System allows local attackers to gain root privileges.
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</synopsis>
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<product type="ebuild">200402-02</product>
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<announced>February 11, 2004</announced>
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<revised>February 11, 2004: 01</revised>
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<access>local</access>
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<affected>
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<package name="x11-base/xfree" auto="yes" arch="*">
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<vulnerable range="lt">4.3.99.902-r1</vulnerable>
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<unaffected range="eq">4.2.1-r3</unaffected>
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<unaffected range="eq">4.3.0-r4</unaffected>
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<unaffected range="ge">4.3.99.902-r1</unaffected>
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</package>
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</affected>
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<background>
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<p>
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XFree86, provides a client/server interface between display
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hardware and the desktop environment while also providing both the
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windowing infrastructure and a standardized API. XFree86 is
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platform independent, network-transparent and extensible.
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</p>
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</background>
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<description>
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<p>
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Exploitation of a buffer overflow in The XFree86 Window System
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discovered by iDefence allows local attackers to gain root
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privileges.
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</p>
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<p>
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The problem exists in the parsing of the 'font.alias' file. The X
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server (running as root) fails to check the length of the user
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provided input, so a malicious user may craft a malformed
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'font.alias' file causing a buffer overflow upon parsing,
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eventually leading to the execution of arbitrary code.
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</p>
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<p>
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To reproduce the overflow on the command line one can run:
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</p>
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<code>
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# cat > fonts.dir <<EOF
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1
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word.bdf -misc-fixed-medium-r-semicondensed--13-120-75-75-c-60-iso8859-1
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EOF
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# perl -e 'print "0" x 1024 . "A" x 96 . "\n"' > fonts.alias
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# X :0 -fp $PWD</code>
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<p>
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{Some output removed}... Server aborting... Segmentation fault (core dumped)
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</p>
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</description>
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<impact type="high">
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<p>
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Successful exploitation can lead to a root compromise provided
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that the attacker is able to execute commands in the X11
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subsystem. This can be done either by having console access to the
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target or through a remote exploit against any X client program
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such as a web-browser, mail-reader or game.
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</p>
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</impact>
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<workaround>
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<p>
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No immediate workaround is available; a software upgrade is required.
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</p>
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<p>
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Gentoo has released XFree 4.2.1-r3, 4.3.0-r4 and 4.3.99.902-r1 and
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encourages all users to upgrade their XFree86
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installations. Vulnerable versions are no longer available in
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Portage.
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</p>
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</workaround>
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<resolution>
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<p>
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All users are recommended to upgrade their XFree86 installation:
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</p>
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<code>
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# emerge sync
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# emerge -pv x11-base/xfree
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# emerge x11-base/xfree</code>
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</resolution>
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<references>
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<uri
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link="http://cve.mitre.org/cgi-bin/cvename.cgi?name=CAN-2004-0083">CVE: CAN-2004-0083</uri>
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<uri link="http://www.idefense.com/application/poi/display?id=72&type=vulnerabilities">Vulnerability:
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XFree86 Font Information File Buffer Overflow</uri>
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</references>
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</glsa>
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