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TITLE:
X.Org X11 Multiple Vulnerabilities

SECUNIA ADVISORY ID:
SA24741

VERIFY ADVISORY:
http://secunia.com/advisories/24741/

CRITICAL:
Less critical

IMPACT:
Exposure of sensitive information, Privilege escalation, DoS

WHERE:
Local system

SOFTWARE:
X Window System 11 (X11) 7.x
http://secunia.com/product/8806/
X Window System 11 (X11) 6.x
http://secunia.com/product/3913/

DESCRIPTION:
Some vulnerabilities have been reported in X.Org X11, which
potentially can be exploited by malicious, local users to disclose
sensitive information, cause a DoS (Denial of Service), and gain
escalated privileges.

1) An integer overflow exists within the parsing of BDF fonts. This
can be exploited to cause a heap-based buffer overflow via a
specially crafted BDF font.

Successful exploitation may allow the execution of arbitrary code
with escalated privileges.

2) An integer overflow exists within the parsing of the "fonts.dir"
fonts information file. This can be exploited to cause a heap-based
buffer overflow via a specially crafted fonts information file that
specifies an element count of more than 1,073,741,824 in the first
line.

Successful exploitation may allow the execution of arbitrary code
with escalated privileges.

3) An input validation error exists within the
"ProcXCMiscGetXIDList()" function of the XC-MISC extension. This can
be exploited to cause a stack-based (if the "alloca()" function is
available) or heap-based memory corruption by passing specially
crafted parameters to the function.

Successful exploitation may allow the execution of arbitrary code
with escalated privileges.

4) An integer overflow exists within the "XGetPixel()" function in
ImUtil.c. This can be exploited to cause a crash or disclose
potentially sensitive information by passing specially crafted
parameters to the function.

Vulnerabilities #1 and #2 are reported in X.Org X11R7.1,
vulnerability #3 is reported in X.org server version 7.1-1.1.0, and
vulnerability #4 is reported in libX11 version 1.0.3. Other versions
may also be affected.

SOLUTION:
Fixed in the source code management repository.

PROVIDED AND/OR DISCOVERED BY:
1, 2) Greg MacManus, iDefense Labs
3) Sean Larsson, iDefense Labs
4) Sami Liedes

ORIGINAL ADVISORY:
http://labs.idefense.com/intelligence/vulnerabilities/display.php?id=501
http://labs.idefense.com/intelligence/vulnerabilities/display.php?id=502
http://labs.idefense.com/intelligence/vulnerabilities/display.php?id=503

http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=414045

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