Multiple Vendor ImageMagick Multiple Integer Overflow Vulnerabilities

iDefense Security Advisory 09.19.07
http://labs.idefense.com/intelligence/vulnerabilities/
Sep 19, 2007

I. 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/

II. DESCRIPTION

Remote exploitation of multiple integer overflow vulnerabilities in
ImageMagick, as included in various vendors' operating system
distributions, allows attackers to crash applications using the
ImageMagick library, and in some cases, execute arbitrary code.

Several integer overflow vulnerabilities have been identified in
ImageMagick's handling of various file formats. By creating a specially
crafted DCM, DIB, XBM, XCF, or XWD image file, an attacker can cause a
heap buffer of insufficient size to be allocated. This results in a
heap-based buffer overflow.

III. ANALYSIS

Exploitation of these vulnerabilities allows an attacker to crash the
programs using ImageMagick library, or execute arbitrary code in the
context of the user.

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.

IV. DETECTION

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

V. 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/dib.*
  /usr/lib/ImageMagick-*/modules*/coders/xbm.*
  /usr/lib/ImageMagick-*/modules*/coders/xcf.*
  /usr/lib/ImageMagick-*/modules*/coders/xwd.*

VI. 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

VII. CVE INFORMATION

The Common Vulnerabilities and Exposures (CVE) project has assigned the
name CVE-2007-4986 to this issue. This is a candidate for inclusion in
the CVE list (http://cve.mitre.org/), which standardizes names for
security problems.

VIII. DISCLOSURE TIMELINE

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

IX. CREDIT

These vulnerabilities were reported to iDefense by regenrecht.

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X. LEGAL NOTICES

Copyright © 2007 iDefense, Inc.

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at the time of publishing based on currently available information. Use
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