Adobe Acrobat Reader XML Forms Data Format Buffer Overflow

[NGSSoftware Insight Security Research <nisr () nextgenss com>]

NGSSoftware Insight Security Research Advisory

Name: Adobe Acrobat Reader XML Forms Data Format Buffer Overflow
Systems Affected: Adobe Acrobat Reader version 5.1
Severity: High Risk
Vendor URL: http://www.adobe.com/
Author: David Litchfield [ david () ngssoftware com ]
Date Vendor Notified:    7th February 2004
Date of Public Advisory: 3rd March 2004
Advisory number: #NISR03022004
Advisory URL: http://www.ngssoftware.com/advisories/adobexfdf.txt

Description
***********
Adobe Acrobat Reader is a viewer that renders PDF documents. The Reader
can be extended using the XML Forms Data Format or XFDF. XFDF is a format
for representing forms data and annotations in a PDF document. XFDF files
have a .xfdf extention and are rendered automatically on download when
using applications such as Internet Explorer. Also note that, regardless
of the file extention if the MIME type is set to
"application/vnd.adobe.xfdf" the file will be treated as a XFDF. When
parsing an XFDF document the Adobe Reader suffers from a classic stack
based buffer overflow vulnerability.


Details
*******
When the xfdf file is parsed an unsafe call to sprintf is made in
preparation for outputting a debug message using OutputDebugString.
Whether the process is being debugged or not the vulnerable code is still
called. Rendering the file will trigger the overflow. A user would need to
be enticed to a web site that hosted a malicious xfdf file or sent one via
e-mail.

Fix Information
***************
On contacting Adobe, they confirmed that the current version is no longer
vulnerable and NGSSoftware urgently advises users of Adobe Reader to
upgrade.
http://www.adobe.com/support/downloads/main.html

About NGSSoftware
*****************
NGSSoftware design, research and develop intelligent, advanced application
security assessment scanners. Based in the United Kingdom, NGSSoftware
have offices in the South of London and the East Coast of Scotland.
NGSSoftware's sister company NGSConsulting, offers best of breed security
consulting services, specialising in application, host and network
security assessments.

http://www.ngssoftware.com/

Telephone +44 208 401 0070
Fax +44 208 401 0076

enquiries () ngssoftware com









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