Adobe Reader and Acrobat contain a buffer overflow vulnerability that may allow an attacker to execute arbitrary code.
Adobe Acrobat Reader is software designed to view Portable Document Format (PDF) files. Adobe also distributes the Adobe Acrobat Plug-In to allow users to view PDF files inside of a web browser. Adobe Reader and Acrobat contain a buffer overflow vulnerability in the handling of JBIG2 streams.
Exploit code for this vulnerability is publicly available.
By convincing a user to open a malicious PDF file, an attacker may be able to execute code or cause a vulnerable PDF viewer to crash. The PDF could be emailed as an attachment or hosted on a website.
Adobe Acrobat and Reader integrates itself with the Windows shell. The file pdfshell.dll is used to configure Windows Explorer to launch Adobe components to render, preview, and obtain details from a PDF document, all without actually opening the PDF document itself. Windows Shell integration for Adobe Acrobat and Reader can be disabled by unregistering the pdfshell.dll by running the following command:
regsvr32 /u "%CommonProgramFiles%\Adobe\Acrobat\ActiveX\pdfshell.dll"
Disable the Adobe Acrobat Indexing Service filter
Adobe Reader and Adobe Acrobat install an Indexing Service filter that is used to parse PDF files. These filters are provided by AcroRdIF.dll and AcroIF.dll, respectively. When an application that uses the Adobe IFilters indexes a malicious PDF document, the vulnerability may be triggered. This attack vector can be mitigated by unregistering the Adobe IFilter files.
Adobe Acrobat users should locate the Acrobat directory and run: regsvr32 /u AcroIF.dll
Adobe Reader users should locate the Adobe Reader directory and run: regsvr32 /u AcroRdIF.dll
Note: After disabling the Windows shell integration or the Indexing Service filter by unregistering the appropriate DLL, the Windows Installer MSI resiliency feature may trigger a "repair" of those features when an advertised shortcut for Adobe Reader is clicked. To prevent this from occurring, delete the Adobe Reader icon from the Windows start menu and then re-create a normal, non-advertised shortcut. More details are available in the CERT/CC Vulnerability Analysis Blog.
Do not access PDF documents from untrusted sources
Do not open unfamiliar or unexpected PDF documents, particularly those hosted on web sites or delivered as email attachments. Please see Cyber Security Tip ST04-010.
Thanks to Adobe for information that was used in this report.
This document was written by Will Dormann and Ryan Giobbi.
|Date First Published:||2009-02-20|
|Date Last Updated:||2009-03-18 20:09 UTC|