[NT] Vulnerability in Microsoft Word Could Allow Remote Code Execution (MS05-035)

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Vulnerability in Microsoft Word Could Allow Remote Code Execution
(MS05-035)
------------------------------------------------------------------------

SUMMARY

A remote code execution vulnerability exists in Microsoft Word's font
parsing mechanism. This vulnerability could allow an attacker who
successfully exploited this vulnerable to take complete control of the
affected system.

DETAILS

Affected Software:
* Word 2000, Microsoft Office 2000 Software Service Pack 3 -
<http://www.microsoft.com/downloads/details.aspx?FamilyId=CEE0864B-B196-48F4-A4B9-2ED7FB6D17D2> Download the update (KB895333)
* Word 2002, Microsoft Office XP Software Service Pack 3 -
<http://www.microsoft.com/downloads/details.aspx?FamilyId=A7E7D2C5-1E2A-4FFB-8FC2-B2B217015820> Download the update (KB895589)
* Microsoft Works Suite 2000 -
<http://www.microsoft.com/downloads/details.aspx?FamilyId=CEE0864B-B196-48F4-A4B9-2ED7FB6D17D2> Download the update (KB895333)
* Microsoft Works Suite 2001 -
<http://www.microsoft.com/downloads/details.aspx?FamilyId=CEE0864B-B196-48F4-A4B9-2ED7FB6D17D2> Download the update (KB895333)
* Microsoft Works Suite 2002 -
<http://www.microsoft.com/downloads/details.aspx?FamilyId=A7E7D2C5-1E2A-4FFB-8FC2-B2B217015820> Download the update (KB895589)
* Microsoft Works Suite 2003 -
<http://www.microsoft.com/downloads/details.aspx?FamilyId=A7E7D2C5-1E2A-4FFB-8FC2-B2B217015820> Download the update (KB895589)
* Microsoft Works Suite 2004 -
<http://www.microsoft.com/downloads/details.aspx?FamilyId=A7E7D2C5-1E2A-4FFB-8FC2-B2B217015820> Download the update (KB895589)

Non-Affected Software:
* Microsoft Office 2003 Word
* Microsoft Office Word 2003 Viewer

CVE Information:
<http://www.cve.mitre.org/cgi-bin/cvename.cgi?name=CAN-2005-0564>
CAN-2005-0564

Mitigating Factors for Font Parsing Vulnerability in Word - CAN-2005-0564:
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.
The vulnerability could not be exploited automatically through e-mail. For
an attack to be successful a user must open an attachment this is sent in
an e-mail message.

Workarounds for Font Parsing Vulnerability in Word - CAN-2005-0564:
Do not open or save Microsoft Word files that you receive from un-trusted
sources.
This vulnerability could be exploited when a user opens a file.

FAQ for Font Parsing Vulnerability in Word - Vulnerability -
CAN-2005-0564:
What is the scope of the vulnerability?
This is a remote code execution vulnerability. If a user is 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 impacted
than users who operate with administrative user rights. However, user
interaction is required to exploit this vulnerability.

What causes the vulnerability?
An unchecked buffer in the process used by the affected software to
process fonts.

What might an attacker use the vulnerability to do?
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.

Who could exploit the vulnerability?
Anyone who could persuade a user to open a specially-crafted document can
attempt to exploit these vulnerabilities.

How could an attacker exploit the vulnerability?
An attacker could exploit the vulnerability by sending a specially-crafted
document to the user and by persuading the user to open the file. If the
user opened the file, the affected software could fail and could allow the
attacker to execute arbitrary code.

Can the vulnerability be exploited automatically through an e-mail
message?
No. A user must open a specially-crafted document that an attacker
provided in order for the attacker to attempt to exploit the
vulnerability. Viewing an e-mail message, even if Microsoft Word had been
selected as the default e-mail editor for Microsoft Outlook, would not
expose the vulnerability.

What does the update do?
The update addresses the vulnerability by modifying the way that the
affected software validates the length of a message before it passes the
message to the allocated buffer.

What systems are primarily at risk from the vulnerability?
Workstations and terminal servers are primarily at risk. Servers are only
at risk if users who do not have sufficient administrative credentials are
given the ability to log on to servers and to run programs. However, best
practices strongly discourage allowing this.

When this security bulletin was issued, had this vulnerability been
publicly disclosed?
No. Microsoft received information about this vulnerability through
responsible disclosure. Microsoft had not received any information to
indicate that this vulnerability had been publicly disclosed when this
security bulletin was originally issued.

ADDITIONAL INFORMATION

The original article can be found at:
<http://www.microsoft.com/technet/security/Bulletin/MS05-035.mspx>
http://www.microsoft.com/technet/security/Bulletin/MS05-035.mspx

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