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Vulnerability in Microsoft Internet Information Services Using Active
Server Pages Could Allow Remote Code Execution (MS06-034)
------------------------------------------------------------------------
SUMMARY
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.
DETAILS
Vulnerable Systems:
* Microsoft Windows 2000 Service Pack 4
<http://www.microsoft.com/downloads/details.aspx?FamilyId=c917d6da-da2d-402c-a870-1de3cbd21ebf>
Download the update
* Microsoft Windows XP Professional Service Pack 1 and Microsoft Windows
XP Professional Service Pack 2
<http://www.microsoft.com/downloads/details.aspx?FamilyId=55d3ca3a-97fc-4e22-8ecc-9416ebc993c4>
Download the update
* Microsoft Windows XP Professional x64 Edition
<http://www.microsoft.com/downloads/details.aspx?FamilyId=4e19b792-7505-4453-b460-5a16915443db>
Download the update
* Microsoft Windows Server 2003 and Microsoft Windows Server 2003 Service
Pack 1
<http://www.microsoft.com/downloads/details.aspx?FamilyId=c5e274a8-f962-4944-8878-6b88b1592bbf>
Download the update
* Microsoft Windows Server 2003 for Itanium-based Systems and Microsoft
Windows Server 2003 with Service Pack 1 for Itanium-based Systems
<http://www.microsoft.com/downloads/details.aspx?FamilyId=e2dc245e-d0f3-41b9-b090-68a2118001cb>
Download the update
* Microsoft Windows Server 2003 x64 Edition family
<http://www.microsoft.com/downloads/details.aspx?FamilyId=f29c886d-b896-4fcf-a22b-2c1a53b1a9eb>
Download the update
* Microsoft Internet Information Services (IIS) 6.0
* Microsoft Internet Information Services (IIS) 5.1
* Microsoft Internet Information Services (IIS) 5.0
Immune Systems:
* Microsoft Windows XP Home Service Pack 1 and Microsoft Windows XP Home
Service Pack 2
Internet Information Services Using Malformed Active Server Pages
Vulnerability -
<http://www.cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2006-0026>
CVE-2006-0026:
There is a remote code execution vulnerability in Internet Information
Services (IIS). An attacker could exploit the vulnerability by
constructing a specially crafted Active Server Pages (ASP) file,
potentially allowing remote code execution if the Internet Information
Services (IIS) processes the specially crafted file. An attacker who
successfully exploited this vulnerability could take complete control of
an affected system.
Mitigating Factors for Internet Information Services Using Malformed
Active Server Pages ASP Vulnerability -
<http://www.cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2006-0026>
CVE-2006-0026:
* On IIS 5.0 and IIS 5.1, ASP enabled applications by default run in the
'Pooled Out of Process' application, which means they run in DLLHOST.exe,
which is running in the context of the low privilege IWAM_ account.
* By default, IIS 5.1 on Windows XP Professional and IIS 6.0 on Windows
Server 2003 are not enabled.
* By default, ASP is not enabled on IIS 6.0. If ASP is enabled, it runs
in the context of a W3WP.exe worker process running as the low privilege
'NetworkService' account.
* An attacker would require valid logon credentials to exploit this
vulnerability. However, if a server has been intentionally configured to
allow users, either anonymous or authenticated, to upload web content such
as .ASP pages to web sites, the server could be attacked successfully by
exploiting by this vulnerability.
Workarounds for Internet Information Services Using Malformed Active
Server Pages Vulnerability -
<http://www.cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2006-0026>
CVE-2006-0026:
We have not identified any workarounds for this vulnerability.
FAQ Workarounds for Internet Information Services Malformed Active Server
Pages Vulnerability -
<http://www.cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2006-0026>
CVE-2006-0026:
What is the scope of the vulnerability?
There is a remote code execution vulnerability in Internet Information
Services (IIS) that results from the way that IIS handles Active Server
Pages (ASP). An attacker could exploit the vulnerability by constructing a
specially crafted Active Server Pages (ASP) file, which could potentially
allow remote code execution if the Internet Information Services (IIS)
processed the file. An attacker who successfully exploited this
vulnerability could take complete control of an affected system.
What causes the vulnerability?
An unchecked buffer in IIS.
What is Active Server Pages (ASP)?
Microsoft Active Server Pages (ASP) is a server-side scripting technology
that can be used to create dynamic and interactive Web applications. An
ASP page is an HTML page that contains server-side scripts that are
processed by the Web server before being sent to the user's browser.
What might an attacker use the vulnerability to do?
An attacker who successfully exploited this vulnerability could take
complete control of the affected system.
Who could exploit the vulnerability?
An attacker would require valid logon credentials to the server in order
to exploit the vulnerability. However if a server had been purposely
configured to allow users, either anonymous or authenticated, to upload
web content such as .ASP pages to web sites, the server could be attacked
by exploit this vulnerability.
How could an attacker exploit the vulnerability?
An attacker could try to exploit the vulnerability by creating a specially
crafted ASP file and uploading the file to an affected system. If IIS
processed the file it could then cause the affected system to execute
code.
What systems are primarily at risk from the vulnerability?
Windows 2000 Service Pack 4 systems running IIS 5.0 are primarily at risk
from this vulnerability because IIS is enabled by default. Windows XP
Professional and Windows Server 2003 are also at risk if the service is
enabled.
Could the vulnerability be exploited over the Internet?
Yes. An attacker could try to exploit this vulnerability over the Internet
if they are granted access to write to the server. Firewall best practices
and standard default firewall configurations can help protect against
attacks that originate from the Internet. Microsoft has provided
information about how you can help protect your PC. End users can visit
the <http://go.microsoft.com/fwlink/?LinkId=21169> Protect Your PC Web
site. IT professionals can visit the
<http://go.microsoft.com/fwlink/?LinkId=21171> Security Guidance Center
Web site.
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.
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 Microsoft Security.
The original article can be found at:
<http://www.microsoft.com/technet/security/Bulletin/MS06-034.mspx>
http://www.microsoft.com/technet/security/Bulletin/MS06-034.mspx
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