GLSA-200402-02 : XFree86 Font Information File Buffer Overflow

Critical Nessus Plugin ID 14446


The remote Gentoo host is missing one or more security-related patches.


The remote host is affected by the vulnerability described in GLSA-200402-02 (XFree86 Font Information File Buffer Overflow)

Exploitation of a buffer overflow in The XFree86 Window System discovered by iDefence allows local attackers to gain root privileges.
The problem exists in the parsing of the 'font.alias' file. The X server (running as root) fails to check the length of the user provided input, so a malicious user may craft a malformed 'font.alias' file causing a buffer overflow upon parsing, eventually leading to the execution of arbitrary code.
To reproduce the overflow on the command line one can run:
# cat > fonts.dir <<EOF 1 word.bdf -misc-fixed-medium-r-semicondensed--13-120-75-75-c-60-iso8859-1 EOF # perl -e 'print '0' x 1024 . 'A' x 96 . '\\n'' > fonts.alias # X :0 -fp $PWD {Some output removed}... Server aborting... Segmentation fault (core dumped) Impact :

Successful exploitation can lead to a root compromise provided that the attacker is able to execute commands in the X11 subsystem. This can be done either by having console access to the target or through a remote exploit against any X client program such as a web-browser, mail-reader or game.
Workaround :

No immediate workaround is available; a software upgrade is required.
Gentoo has released XFree 4.2.1-r3, 4.3.0-r4 and and encourages all users to upgrade their XFree86 installations. Vulnerable versions are no longer available in Portage.


All users are recommended to upgrade their XFree86 installation:
# emerge sync # emerge -pv x11-base/xfree # emerge x11-base/xfree

See Also

Plugin Details

Severity: Critical

ID: 14446

File Name: gentoo_GLSA-200402-02.nasl

Version: $Revision: 1.13 $

Type: local

Published: 2004/08/30

Modified: 2015/04/13

Dependencies: 12634

Risk Information

Risk Factor: Critical


Base Score: 10

Vector: CVSS2#AV:N/AC:L/Au:N/C:C/I:C/A:C

Vulnerability Information

CPE: p-cpe:/a:gentoo:linux:xfree, cpe:/o:gentoo:linux

Required KB Items: Host/local_checks_enabled, Host/Gentoo/release, Host/Gentoo/qpkg-list

Patch Publication Date: 2004/02/11

Reference Information

CVE: CVE-2004-0083

GLSA: 200402-02