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RealNetworks RealPlayer CMediumBlockAllocator Integer Overflow Vulnerability
iDefense Security Advisory 02.01.10: RealNetworks RealPlayer CMediumBlockAllocator Integer Overflow Vulnerability
iDefense Security Advisory 02.01.10: RealNetworks RealPlayer CMediumBlockAllocator Integer Overflow Vulnerability

iDefense Security Advisory 02.01.10 
Feb 01, 2010


RealPlayer is an application for playing various media formats,
developed by RealNetworks Inc. Since late 2003, Real Player has been
based on the open-source Helix Player. More information can be found at
the URLs shown. For more information, see the vendor's site found at the
following links. 


Remote exploitation of an integer overflow vulnerability in RealNetworks
Inc.'s Real Player could allow an attacker to execute arbitrary code
with the privileges of the current user.

This problem specifically exists in the CMediumBlockAllocator::Alloc
method. When calculating the size of a memory allocation, an integer
overflow occurs. This leads to heap corruption, which can result in the
execution of arbitrary code.


Exploitation of this vulnerability results in the execution of arbitrary
code with the privileges of the user executing Real Player.

To be successful, an attacker must persuade a user to use Real Player to
view specially crafted media. This could be accomplished via a Web page
or direct link to the malicious media.


iDefense has confirmed the existence of this vulnerability in Real
Player versions 10.5 (build and 11 (build on
Windows. Other versions may also be affected. RealNetworks has provided
the following matrix of vulnerable products:

Windows RealPlayer 11.0.0 - 11.0.4
Windows RealPlayer 10.5
Mac RealPlayer 10
Linux RP10


iDefense is currently unaware of any effective workaround for this


RealNetworks has released a patch which addresses this issue.
Information about downloadable vendor updates can be found by clicking
on the URLs shown. 


The Common Vulnerabilities and Exposures (CVE) project has assigned the
name CVE-2009-4248 to this issue. This is a candidate for inclusion in
the CVE list (, which standardizes names for 
security problems.


01/11/2008  Initial Contact
01/11/2009  Initial Response
02/01/2010  Coordinated public disclosure.


The discoverer of this vulnerability wishes to remain anonymous.

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