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Security Services

Real Networks RealPlayer Compressed GIF Handling Integer Overflow



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 Real Networks Inc.'s RealPlayer version 11 could allow an attacker to execute arbitrary code.

iDefense Labs has confirmed the existence of an integer overflow issue within RealPlayer when handling compressed GIF files. The vulnerability occurs in the CGIFCodec::InitDecompress() function, which does not properly validate a field in the GIF file before using it in an arithmetic operation that calculates the size of a heap buffer. This issue leads to heap corruption, which can result in the execution of arbitrary code.


Exploitation of this issue allows an attacker to execute arbitrary code within the security context of the current user. An attacker would need to entice a victim into opening a RTSP stream. Upon the victim opening the stream, the attack would inject a malformed compressed GIF image into a RTSP stream to exploit this issue. Other attack vectors are likely to exist; however, this was the vector tested within iDefense Labs. It should be noted that RealPlayer can be instantiated within a Web browser. This means an attacker could host a malicious Web page and entice a victim into visiting this page. Upon visiting the page, exploitation would occur.


iDefense confirmed RealPlayer version 11 is vulnerable to this issue. RealNetworks provided the following matrix of affected software:

Windows RealPlayer 11.0.0 - 11.0.4
Mac RealPlayer 10


iDefense recommends applying the following workarounds until a patch resolving this issue is made publicly available by Real Networks Inc. RealPlayer users should change the GIF filetype association to another application. It is also recommended that RealPlayer users disable the RealPlayer plugins contained within the Web browsers plugins directory by changing the file permissions to deny execution of these files. These workarounds will limit the functionality of RealPlayer by disabling GIF support and web browser plugin features. These workarounds may not mitigate all exploitation vectors but will likely prevent the majority of likely scenarios.


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-2009-4245 to this issue. This is a candidate for inclusion in the CVE list (, which standardizes names for security problems.


05/13/2008 Initial Contact
05/03/2008 Initial Response
02/01/2010 Coordinated public disclosure.


The discoverer of this vulnerability wishes to remain anonymous.

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Copyright © 2010 Verisign, Inc.

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