[UNIX] Multiple Vendor libgsf Heap Overflow

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  Multiple Vendor libgsf Heap Overflow
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SUMMARY

The  <http://freshmeat.net/projects/libgsf/> GNOME Structured File Library 
is a utility library for reading and writing structured file formats. This 
library replaces libole2 and is used in projects such as gnumeric, 
mrproject, abiword, libwv2 and koffice. It is generally used to access MS 
OLE2 streams.

Remote exploitation of a heap overflow vulnerability in libgsf, as 
included in various vendors' operating system distributions, could allow 
an attacker to execute arbitrary code.

DETAILS

Vulnerable Systems:
 * Gnome Structured File library(libgsf) version 1.14.0

Immune Systems:
 * Gnome Structured File library(libgsf) version 1.14.2

The problem specifically exists in the 'ole_init_info' function; the 
function only obtains enough for the number specified in 'num_bat' when 
allocating memory. Later, when reading the file contents, the number 
specified in 'num_metabat' is used as the bounds for a loop. Due to 
insufficient validation of the aforementioned variables, an attacker could 
cause a heap overflow.

Successful exploitation of this vulnerability requires an attacker to 
persuade a user into opening a specially crafted OLE document. If 
successful, the attacker could execute arbitrary code with the permissions 
of the victim.

Inside of the 'ole_info_read_metabat' function, values read from the file 
are validated to be within a range which depends on the size of the file. 
Successful exploitation may be somewhat mitigated by this validation. 
However, as file size increases, the number of allowed values increases.

Vendor Status:
The libgsf maintainers have addressed this problem with version 1.14.2.

CVE Information:
 <http://www.cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2006-4514> 
CVE-2006-4514

Disclosure Timeline:
 * 08/17/2006 - Initial vendor notification
 * 08/17/2006 - Initial vendor response
 * 11/30/2006 - Coordinated public disclosure


ADDITIONAL INFORMATION

The information has been provided by iDefense.
The original article can be found at:
 
<http://labs.idefense.com/intelligence/vulnerabilities/display.php?id=446> 
http://labs.idefense.com/intelligence/vulnerabilities/display.php?id=446



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