Flood pixel attack in Imagemagick

Post any defects you find in the released or beta versions of the ImageMagick software here. Include the ImageMagick version, OS, and any command-line required to reproduce the problem. Got a patch for a bug? Post it here.
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Flood pixel attack in Imagemagick

Post by Ganesha » 2014-08-01T00:06:38-07:00

Hi ,

I checked whether Imagemagick handles pixel attacks through this command

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convert lottapixel.jpg -resize 700x test.png
The convert command takes more and more time couldn't get an output.

Here is details of pixel attack https://hackerone.com/reports/390

Is there any ways to find the pixels of the input image and then send to convert command? or any other solutions?

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Re: Flood pixel attack in Imagemagick

Post by magick » 2014-08-01T03:16:05-07:00

You are prevent DOS attacts by setting the ImageMagick policy. Here is the one we use on our systems:

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<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE policymap [
<!ELEMENT policymap (policy)+>
<!ELEMENT policy (#PCDATA)>
<!ATTLIST policy domain (delegate|coder|filter|path|resource) #IMPLIED>
<!ATTLIST policy rights CDATA #IMPLIED>
<!ATTLIST policy pattern CDATA #IMPLIED>
<!ATTLIST policy value CDATA #IMPLIED>
  Configure ImageMagick policies.

  Domains include system, delegate, coder, filter, path, or resource.

  Rights include none, read, write, and execute.  Use | to combine them,
  for example: "read | write" to permit read from, or write to, a path.

  Use a glob expression as a pattern.

  Suppose we do not want users to process MPEG video images:

    <policy domain="delegate" rights="none" pattern="mpeg:decode" />

  Here we do not want users reading images from HTTP:

    <policy domain="coder" rights="none" pattern="HTTP" />

  Lets prevent users from executing any image filters:

    <policy domain="filter" rights="none" pattern="*" />

  The /repository file system is restricted to read only.  We use a glob
  expression to match all paths that start with /repository:
    <policy domain="path" rights="read" pattern="/repository/*" />

  Any large image is cached to disk rather than memory:

    <policy domain="resource" name="area" value="1GB"/>

  Define arguments for the memory, map, area, and disk resources with
  SI prefixes (.e.g 100MB).  In addition, resource policies are maximums for
  each instance of ImageMagick (e.g. policy memory limit 1GB, -limit 2GB
  exceeds policy maximum so memory limit is 1GB).
  <policy domain="resource" name="temporary-path" value="/tmp"/> 
  <policy domain="resource" name="memory" value="256MiB"/> 
  <policy domain="resource" name="map" value="512MiB"/> 
  <policy domain="resource" name="area" value="128MB"/> 
  <policy domain="resource" name="disk" value="1GiB"/> 
  <policy domain="resource" name="file" value="768"/> 
  <policy domain="resource" name="thread" value="2"/>
  <policy domain="resource" name="throttle" value="0"/> 
  <policy domain="resource" name="time" value="120"/> 
  <policy domain="system" name="precision" value="6"/> 
  <policy domain="cache" name="shared-secret" value="No more secrets."/>

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