Potential issue in Adobe Reader

Adobe is aware of a potential issue in Adobe Reader posted publicly today on the Full Disclosure list. A proof-of-concept file demonstrating a Denial of Service was published. Arbitrary code execution has not been demonstrated, but may be possible. We are currently investigating this issue. In the meantime, users of Adobe Reader 9.2 or later and 8.1.7 or later can utilize the JavaScript Blacklist Framework to prevent the issue by following the instructions below. Note that Adobe Acrobat is not affected by this issue.


Adobe Reader 9.2 and later and Adobe Reader 8.1.7 and later – Windows

On Windows, the JavaScript Blacklist can be in two locations. Please review the following options and then create the registry key of your choice:

Enterprise list: This blacklist helps enterprises roll out policies that block exploitable API(s) from executing in their environment. Populating the blacklist in this location is the responsibility of the enterprise. Adobe patches never modify this registry location.
To create the registry key:
HKLM\SOFTWARE\Policies\Adobe\<product>\<version>\FeatureLockDown\cJavaScriptPerms\tBlackList

Adobe’s update/patch list: The Adobe blacklist is modified by Adobe Reader patches whenever an API is deemed vulnerable. APIs are also removed from the blacklist whenever a fix for a vulnerability is provided by the current patch.
To create the registry key:
HKLM\SOFTWARE\Adobe\<product>\<version>\JavaScriptPerms\tBlackList

    On a 64 bit Windows system, the path is:
    HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\Adobe

->To prevent this particular issue, add the following value to the registry key created in the previous step (case sensitive):
Doc.printSeps

->Exit and restart the application

Adobe Reader 9.2 and later and Adobe Reader 8.1.7 and later – Macintosh

  1. On your Macintosh computer, go to the Applications folder or to the location where you have Adobe Reader installed.
  2. Right-click on Adobe Reader
  3. Click on Show Package Contents
  4. Expand Contents
  5. Expand MacOS
  6. Expand Preferences
  7. Create a backup of the FeatureLockDown file.
  8. Right-click on FeatureLockDown.
  9. Open With TextEdit.
  10. Just before the last >> add the following line to the FeatureLockDown file (case sensitive):
    /JavaScriptPerms [ /c << /BlackList [ /t (Doc.printSeps) ] >> ]
  11. Save the file
  12. Restart Adobe Reader

Adobe Reader 9.2 and later – UNIX

  1. Go to the Global Prefs file at:
    /Reader/GlobalPrefs/reader_prefs
  2. Add the following line to the file:
    /JavaScriptPerms [/c << /BlackList [/t (Doc.printSeps) ] >> ]

For more details, see the following Knowledge Base articles:
http://kb2.adobe.com/cps/504/cpsid_50431.html
http://kb2.adobe.com/cps/532/cpsid_53237.html

We will continue to provide updates on this issue via the Adobe PSIRT blog and/or the Security Advisory section of the Adobe website as appropriate.

November 8, 2010 Update:
We plan to resolve this issue in the update for Adobe Reader and Acrobat 9.4 and earlier 9.x versions scheduled for release during the week of November 15, 2010, mentioned in Security Advisory APSA10-05. We have assigned CVE-2010-4091 to this issue. As of today, Adobe is not aware of any exploits in the wild or public exploit code for this issue.

This posting is provided “AS IS” with no warranties and confers no rights.

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