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Multiple Vendor ImageMagick Multiple Denial of Service Vulnerabilities

09.19.07

BACKGROUND

ImageMagick is a suite of image manipulation tools (animate, composite, conjure, convert, display, identify, import, mogrify and montage) that are sometimes used by other applications for processing image files. For more information about ImageMagick, visit the vendor's site at the following URL.

http://www.imagemagick.org/

DESCRIPTION

Remote exploitation of multiple denial of service vulnerabilities in ImageMagick, as included in various vendors' operating system distributions, allows attackers to consume excessive CPU resources on the target system.

The first vulnerability exists in the ReadDCMImage() function. Since the return value of ReadBlobByte() is not properly checked, it can enter an infinite loop.

The second vulnerability exists in the ReadXCFImage() function. Since the return value of ReadBlobMSBLong() is not properly checked, it can enter an infinite loop.

ANALYSIS

Exploitation of these vulnerabilities allows an attacker to consume excessive CPU resource on the system using the ImageMagick library to process images.

One way of exploiting these vulnerabilities is to persuade a targeted user to open a malicious image file with a program that utilizes the ImageMagick library.

As the tools that are part of ImageMagick are sometimes used as helper tools by other applications, this user may be the same as the web server user. This scenario is somewhat more severe than the previously described attack vector since the image processing can occur automatically.

DETECTION

iDefense Labs confirmed that ImageMagick version 6.3.4 is vulnerable. It is suspected that other versions of ImageMagick are also vulnerable.

WORKAROUND

Exposure to some of these vulnerabilities can be mitigated by moving or deleting the related module files. The file locations may vary between distributions. The globbing expressions listed below correspond to a Red Hat Linux system.

 /usr/lib/ImageMagick-*/modules*/coders/dcm.* /usr/lib/ImageMagick-*/modules*/coders/xcf.* 

VENDOR RESPONSE

The ImageMagick maintainers have addressed these vulnerabilities with the release of version 6.3.5-9. More information is available from the following URL.

http://studio.imagemagick.org/pipermail/magick-announce/2007-September/000037.html

CVE INFORMATION

The Common Vulnerabilities and Exposures (CVE) project has assigned the name CVE-2007-4985 to this issue. This is a candidate for inclusion in the CVE list (http://cve.mitre.org/), which standardizes names for security problems.

DISCLOSURE TIMELINE

09/04/2007 Initial vendor notification
09/05/2007 Initial vendor response
09/19/2007 Coordinated public disclosure

CREDIT

These vulnerabilities were reported to iDefense by regenrecht.

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LEGAL NOTICES

Copyright © 2007 Verisign, Inc.

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Disclaimer: The information in the advisory is believed to be accurate at the time of publishing based on currently available information. Use of the information constitutes acceptance for use in an AS IS condition. There are no warranties with regard to this information. Neither the author nor the publisher accepts any liability for any direct, indirect, or consequential loss or damage arising from use of, or reliance on, this information.