US-CERT Technical Cyber Security Alert TA10-279A -- Adobe Reader and Acrobat Affected by Multiple Vulnerabilities

                    National Cyber Alert System

              Technical Cyber Security Alert TA10-279A

Adobe Reader and Acrobat Affected by Multiple Vulnerabilities

   Original release date: October 06, 2010

   Last revised: --

   Source: US-CERT

Systems Affected

     * Adobe Reader 9.3.4 and earlier versions for Windows, Macintosh, and UNIX

     * Adobe Acrobat 9.3.4 and earlier versions for Windows and Macintosh

     * Adobe Reader 8.2.4 and earlier versions for Windows, Macintosh, and UNIX

     * Adobe Acrobat 8.2.4 and earlier versions for Windows and Macintosh

Overview

   Adobe has released Security Bulletin APSB10-21, which describes

   multiple vulnerabilities affecting Adobe Reader and Acrobat.

I. Description

   Adobe Security Bulletin APSB10-21 describes a number of

   vulnerabilities affecting Adobe Reader and Acrobat. These

   vulnerabilities affect Reader and Acrobat 9.3.4, earlier 9.x

   versions, 8.2.4, and earlier 8.x versions.

   An attacker could exploit these vulnerabilities by convincing a

   user to open a specially crafted PDF file. The Adobe Reader browser

   plug-in, which can automatically open PDF documents hosted on a

   website, is available for multiple web browsers and operating

   systems.

   Additional information is available in US-CERT Vulnerability Note

   VU#491991.

II. Impact

   These vulnerabilities could allow a remote attacker to execute

   arbitrary code, write arbitrary files or folders to the file

   system, escalate local privileges, or cause a denial of service on

   an affected system as the result of a user opening a malicious PDF

   file.

III. Solution

   Update

   Adobe has released updates to address this issue. Users are

   encouraged to read Adobe Security Bulletin APSB10-21 and update

   vulnerable versions of Adobe Reader and Acrobat.

   Disable JavaScript in Adobe Reader and Acrobat

   Disabling JavaScript may prevent some exploits from resulting in

   code execution. Acrobat JavaScript can be disabled using the

   Preferences menu (Edit -> Preferences -> JavaScript; uncheck Enable

   Acrobat JavaScript).

   Adobe provides a framework to blacklist specific JavaScipt APIs. If

   JavaScript must be enabled, this feature may be useful when

   specific APIs are known to be vulnerable or used in attacks.

   Prevent Internet Explorer from automatically opening PDF files

   The installer for Adobe Reader and Acrobat configures Internet

   Explorer to automatically open PDF files without any user

   interaction. This behavior can be reverted to a safer option that

   prompts the user by importing the following as a .REG file:

   Windows Registry Editor Version 5.00

   [HKEY_CLASSES_ROOT\AcroExch.Document.7]

   "EditFlags"=hex:00,00,00,00

   Disable the display of PDF files in the web browser

   Preventing PDF files from opening inside a web browser will

   partially mitigate this vulnerability. If this workaround is

   applied, it may also mitigate future vulnerabilities.

   To prevent PDF files from automatically being opened in a web

   browser, do the following:

   1. Open Adobe Acrobat Reader.

   2. Open the Edit menu.

   3. Choose the Preferences option.

   4. Choose the Internet section.

   5. Uncheck the "Display PDF in browser" checkbox.

   Do not access PDF files from untrusted sources

   Do not open unfamiliar or unexpected PDF files, particularly those

   hosted on websites or delivered as email attachments. Please see

   Cyber Security Tip ST04-010.

IV. References

 * Security update available for Adobe Reader and Acrobat -

   <http://www.adobe.com/support/security/bulletins/apsb10-21.html>

 * US-CERT Vulnerability Note VU#491991 -

   <http://www.kb.cert.org/vuls/id/491991>

 * Adobe Reader and Acrobat JavaScript Blacklist Framework -

   <http://kb2.adobe.com/cps/504/cpsid_50431.html>

 ____________________________________________________________________

   The most recent version of this document can be found at:

     <http://www.us-cert.gov/cas/techalerts/TA10-279A.html>

 ____________________________________________________________________

   Feedback can be directed to US-CERT Technical Staff. Please send

   email to <[e-mail]> with "TA10-279A Feedback VU#491991" in

   the subject.

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Revision History

  October 06, 2010: Initial release