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Security Best Practice: Protect Yourself from PDF Containing Obfuscated Name Objects and Obfuscated JavaScript Filter Name Exploits

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Check Point Reference: SBP-2009-28
Date Published:
Severity:
Source: Didier Stevens Blog
Protection Provided by: Security Gateway
  • R70
Who is Vulnerable?
Adobe Acrobat Reader 8.1.2 and possibly earlier versions
Foxit Reader 2.2 and possibly earlier versions
Vulnerability Description
New exploits were released for several remote code execution vulnerabilities that were discovered in the way Adobe Acrobat Reader and Foxit Reader handle specially crafted PDF files. Portable Document Format (PDF) is an open file format created by Adobe Systems. It is used for representing two-dimensional documents in a device and resolution independent fixed-layout document format.
Although various security products provide coverage against many malformed PDF files vulnerabilities, these new exploits could potentially bypass security products by using PDF files that contain obfuscated name objects and obfuscated JavaScript filter names.
Vulnerability Details
PDF authoring tools do not make use of such obfuscation techniques, thus indicating that the PDF file was manually modified and manipulated, in all likelihood, to confuse security products.
These exploits can bypass security rules - since the exploits are being thoroughly obfuscated, IDS and IPS systems will not recognize them and will allow them to pass without any notification.

Protection Overview
These protections will detect and block PDF files with obfuscated name objects and obfuscated JavaScript filter names.

In order for the protection to be activated, update your Security Gateway product to the latest IPS update. For information on how to update IPS, go to SBP-2006-05, Protection tab and select the version of your choice.

To configure the defense, select your product from the list below and follow the related protection steps.

Security Gateway R70

How Can I Protect My Network?

1. In the IPS tab, click Protections > By Protocol > Application Intelligence > Content Protection > Adobe Reader and Acrobat.
2. In the right pane, double-click the following protections:

PDF Containing Obfuscated Name Objects

PDF Containing Obfuscated JavaScript Filter Name

3. In the Protection Details window, click on Edit. Choose the protection's Action (Override IPS Policy with: Prevent/Detect), and apply Additional Settings.
4. Install policy on all modules.

How Do I Know if My Network is Under Attack?
SmartView Tracker will log the following entries:

Attack Name: Content Protection Violation
Attack Information:
PDF containing obfuscated name objects
PDF containing obfuscated JavaScript filter name