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Vulnerability in Microsoft Publisher Allows Code Execution (MS06-054)
------------------------------------------------------------------------
SUMMARY
A remote code execution vulnerability exists in Publisher. An attacker
could exploit this vulnerability when Publisher parses a file with a
malformed string.
If a user were logged on with administrative user rights, an attacker who
successfully exploited this vulnerability could take complete control of
an affected system. An attacker could then install programs; view, change,
or delete data; or create new accounts with full user rights. Users whose
accounts are configured to have fewer user rights on the system could be
less affected than users who operate with administrative user rights.
DETAILS
Affected Software:
* Microsoft Office 2000 Service Pack 3 -
<http://www.microsoft.com/downloads/details.aspx?FamilyId=461A126B-596F-4E84-99FD-03554AC55213>
Download the update (KB894540)
* Office Publisher 2000
* Microsoft Office XP Service Pack 3 -
<http://www.microsoft.com/downloads/details.aspx?FamilyId=0356B9FB-2CD5-4A50-95F6-54846D39B6EA>
Download the update (KB894541)
* Office Publisher 2002
* Microsoft Office 2003 Service Pack 1 and Service Pack 2 -
<http://www.microsoft.com/downloads/details.aspx?FamilyId=2EEB43F1-E2B6-4B78-98A1-E8B04242438A>
Download the update (KB894542)
* Office Publisher 2003
CVE Information:
<http://www.cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2006-0001>
CVE-2006-0001
Mitigating Factors for Microsoft Publisher Vulnerability - CVE-2006-0001:
* An attacker who successfully exploited this vulnerability could gain
the same user rights as the local user. Users whose accounts are
configured to have fewer user rights on the system could be less impacted
than users who operate with administrative user rights.
* In a Web-based attack scenario, an attacker would have to host a Web
site that contains a Publisher file that is used to attempt to exploit
this vulnerability. In addition, compromised Web sites and Web sites that
accept or host user-provided content could contain specially crafted
content that could exploit this vulnerability An attacker would have no
way to force users to visit a malicious Web site. Instead, an attacker
would have to persuade them to visit the Web site, typically by getting
them to click a link that takes them to the attacker's site.
* The vulnerability cannot be exploited automatically through e-mail. For
an attack to be successful a user must open an attachment that is sent in
an e-mail message.
* Users who have installed and are using the Office Document Open
Confirmation Tool for Office 2000 will be prompted with Open, Save, or
Cancel before opening a document.
* By default, Publisher is only installed on the Professional Suites of
Office.
Workarounds for Microsoft Publisher Vulnerability - CVE-2006-0001:
Microsoft has tested the following workarounds. Although these workarounds
will not correct the underlying vulnerability, they help block known
attack vectors. When a workaround reduces functionality, it is identified
in the following section.
* Do not open or save Publisher files that you receive from un-trusted
sources or that you receive unexpectedly from trusted sources.
This vulnerability could be exploited when Publisher opens a file.
FAQ for Microsoft Publisher Vulnerability - CVE-2006-0001:
What is the scope of the vulnerability?
A remote code execution vulnerability exists in Publisher. An attacker
could exploit this vulnerability when Publisher parses a file with a
malformed string.
If a user were logged on with administrative user rights, an attacker who
successfully exploited this vulnerability could take complete control of
an affected system. An attacker could then install programs; view, change,
or delete data; or create new accounts with full user rights. Users whose
accounts are configured to have fewer user rights on the system could be
less affected than users who operate with administrative user rights.
What causes the vulnerability?
Publisher does not perform sufficient data validation when processing the
contents of a .pub file. When Publisher opens a specially crafted
Publisher file and parses a malformed string, it may corrupt system memory
in such a way that an attacker could execute arbitrary code.
What might an attacker use the vulnerability to do?
An attacker who successfully exploited this vulnerability could take
complete control of the affected system.
How could an attacker exploit the vulnerability?
In an e-mail attack scenario, an attacker could exploit the vulnerability
by sending a specially-crafted file to the user and by persuading the user
to open the file.
In a Web-based attack scenario, an attacker would have to host a Web site
that contains a Word file that is used to attempt to exploit this
vulnerability. In addition, compromised Web sites and Web sites that
accept or host user-provided content could contain specially crafted
content that could exploit this vulnerability An attacker would have no
way to force users to visit a malicious Web site. Instead, an attacker
would have to persuade them to visit the Web site, typically by getting
them to click a link that takes them to the attacker's site.
What systems are primarily at risk from the vulnerability?
Workstations and terminal servers are primarily at risk. Servers could be
at more risk if administrators allow users to log on to servers and to run
programs. However, best practices strongly discourage allowing this.
What does the update do?
The update removes the vulnerability by modifying the way that Publisher
parses the file and validates the length of a string before passing it to
the allocated buffer.
Does this update contain any changes to functionality?
Yes. After the update for Publisher 2000 or Publisher 2002 is installed,
users will not be able to open Publisher 2.0 files anymore. For more
information, see Microsoft Knowledge Base Article
<http://support.microsoft.com/kb/924685> 924685. In addition, if a user
opens a malformed Publisher file, Publisher may potentially crash but will
not be exploitable.
When this security bulletin was issued, had this vulnerability been
publicly disclosed?
No. Microsoft received information about this vulnerability through
responsible disclosure.
When this security bulletin was issued, had Microsoft received any reports
that this vulnerability was being exploited?
No. Microsoft had not received any information to indicate that this
vulnerability had been publicly used to attack customers and had not seen
any examples of proof of concept code published when this security
bulletin was originally issued.
ADDITIONAL INFORMATION
The information has been provided by Stuart Pearson of Computer Terrorism.
The original article can be found at:
<http://www.microsoft.com/technet/security/Bulletin/MS06-054.mspx>
http://www.microsoft.com/technet/security/Bulletin/MS06-054.mspx
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