Public Vulnerability Reports

Adobe Acrobat Reader 5.0.9 mailListIsPdf() Buffer Overflow Vulnerability



Adobe Acrobat Reader is a program for viewing Portable Document Format
(PDF) documents. More information is available at the following site:


Remote exploitation of a buffer overflow in version 5.09 of Adobe
Acrobat Reader for Unix could allow for execution of arbitrary code.

The vulnerability specifically exists in a the function mailListIsPdf().
This function checks if the input file is an email message containing
a PDF. It unsafely copies user supplied data using strcat into a fixed
sized buffer.


Successful exploitation allows an attacker to execute arbitrary code
under the privileges of the local user. Remote exploitation is possible
by sending a specially crafted e-mail and attaching either the
maliciously crafted PDF document or a link to it.


iDEFENSE has confirmed the existence of this vulnerability in Adobe
Acrobat Reader version 5.0.9 for Unix. Previous versions of Adobe
Acrobat Reader 5 for Unix are suspected also to be vulnerable.


User awareness is the best defense against this class of attack.
Users should be aware of the existence of such attacks and proceed with
caution when following links from suspicious and/or unsolicited e-mail.

Additionally, you may wish to apply the following unofficial patch from
iDEFENSE Labs to the acroread shell script. The acroread shell script
calls the appropriate binary for the platform. The patch adds a check
that ensures that files passed as arguments to acroread are in fact PDF
documents. This patch will not protect against files opened from within
the Acrobat Reader GUI.

The bin/ directory of the application contains an 'acroread' shell
script while the Reader/ directory contains a binary with the same name.
The command 'file acroread', when executed in the same directory as the
shell script, should return the line:

acroread: a /bin/sh script text executable

This result indicates the existence of the appropriate file that the
patch below can be applied to.


--- acroread.orig 2004-10-13 17:25:57.000000000 -0400
+++ acroread 2004-10-13 17:55:43.000000000 -0400
@@ -309,6 +309,16 @@
 if [ -f "$ACRO_EXEC_CMD" ] ; then
+  for CHECK in ${1+"$@"};
+  do
+   [ -f "$CHECK" ] && {
+    file "$CHECK" | grep "PDF document" ||
+    {
+     echo "$CHECK" exists, but is not a PDF document.
+     exit 1;
+    }
+   }
+   done
   exec "$ACRO_EXEC_CMD" ${1+"$@"}
   echo "ERROR: Cannot find $ACRO_EXEC_CMD"

This is not an official patch, and may not operate on your system. This
patch was supplied to mitigate exposure until a vendor supplied patch
became available. The vendor supplied patch, which is now available,
should be applied instead of this patch when possible.


This vulnerability is fixed in Adobe Acrobat Reader 5.0.10 for Unix.
Further details of the vulnerability are available in the following
knowledgebase article:


The Common Vulnerabilities and Exposures (CVE) project has assigned the
name CAN-2004-1152 to this issue. This is a candidate for inclusion
in the CVE list (, which standardizes names for
security problems.


10/14/2004   Initial vendor notification
10/15/2004   Initial vendor response
12/14/2004   Coordinated public disclosure


This vulnerability was discovered by Greg MacManus, iDEFENSE Labs.

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Copyright © 2004 Verisign, Inc.

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at the time of publishing based on currently available information. Use
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