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Microsoft ISA and Proxy Server Web Site Spoofing Vulnerability

Risk
Medium

Date Discovered
11-04-2004

Description
Microsoft ISA and Proxy Server are reportedly prone to a Web site spoofing vulnerability. Successful exploitation of this issue could allow a remote attacker to spoof a trusted Web site.

If a connection were made to the spoofed Web site using SSL, the malicious site would not be able to spoof the certificate of the legitimate site. This would likely cause a warning message to appear to the user.

Microsoft Small Business Server 2000 and 2003 include the affected software.

Symantec AntiVirus
Due to the severity and nature of this threat, we will not be releasing updates at this time. We are, however, constantly monitoring the threat landscape to protect against the latest attacks.

Symantec Network Security 7100 and ManHunt 3
Due to the severity and nature of this threat, we will not be releasing updates at this time. We are, however, constantly monitoring the threat landscape to protect against the latest attacks.

Symantec Enterprise Security Manager Symantec Enterprise Security Manager™ posted an update to the OS Patch Policy that detects and reports systems that are not patched against this vulnerability. Click here for the advisory released November 9, 2004.

Symantec Vulnerability Assessment Symantec Vulnerability Assessment detects and reports this vulnerability. Click here for the advisory released November 9, 2004.

Platforms Affected
Microsoft BackOffice 4.5
Microsoft Windows 2000 Advanced Server
Microsoft Windows 2000 Advanced Server SP1
Microsoft Windows 2000 Advanced Server SP2
Microsoft Windows 2000 Datacenter Server SP1
Microsoft Windows 2000 Datacenter Server SP2
Microsoft Windows 2000 Server
Microsoft Windows 2000 Server SP1
Microsoft Windows 2000 Server SP2
Microsoft Windows NT 4.0

Components Affected
Microsoft ISA Server 2000 SP2
Microsoft ISA Server 2000 SP1
Microsoft ISA Server 2000
Microsoft Proxy Server 2.0 SP1
Microsoft Proxy Server 2.0
Microsoft Small Business Server 2000
Microsoft Small Business Server 2003

Recommendations
Do not follow links provided by unknown or untrusted sources.
To exploit this vulnerability, an attacker would first have to entice a user to visit a malicious Web site. Do not follow links to unfamiliar or untrusted Web sites.

Manually inspect certificate properties.
When establishing an SSL connection to a Web site, always inspect the certificate properties to ensure that they are valid.

Microsoft has released a security bulletin and fixes to address this issue for supported versions.


Microsoft ISA Server 2000 SP2:

Microsoft Upgrade Vulnerability in Microsoft ISA Server 2000 Could Allow Internet Content Spoofing (888258)
http://www.microsoft.com/downloads/details.aspx?familyid=7A4C318F-5AC9-4CF2-8792-A4A62076EBE7&displaylang=enm

Microsoft ISA Server 2000 SP1:
Microsoft Upgrade Vulnerability in Microsoft ISA Server 2000 Could Allow Internet Content Spoofing (888258)
http://www.microsoft.com/downloads/details.aspx?familyid=7A4C318F-5AC9-4CF2-8792-A4A62076EBE7&displaylang=enm

Microsoft ISA Server 2000 :
Microsoft Proxy Server 2.0 SP1:
Microsoft Upgrade Vulnerability in Microsoft® Proxy Server 2.0 Could Allow Internet Content Spoofing (888258)
http://www.microsoft.com/downloads/details.aspx?familyid=55643141-91E3-4474-8134-72887BC6FC18&displaylang=en

Microsoft Proxy Server 2.0:
Microsoft Small Business Server 2000 :
Microsoft Upgrade Vulnerability in Microsoft ISA Server 2000 Could Allow Internet Content Spoofing (888258)
http://www.microsoft.com/downloads/details.aspx?familyid=7A4C318F-5AC9-4CF2-8792-A4A62076EBE7&displaylang=enm

Microsoft Small Business Server 2003 :
Microsoft Upgrade Vulnerability in Microsoft ISA Server 2000 Could Allow Internet Content Spoofing (888258)
http://www.microsoft.com/downloads/details.aspx?familyid=7A4C318F-5AC9-4CF2-8792-A4A62076EBE7&displaylang=enm

References
Source: Knowledge Base Article - 889189
URL: http://support.microsoft.com/kb/889189

Source: Microsoft Security Bulletin MS04-039
URL: http://www.microsoft.com/technet/security/bulletin/ms04-039.mspx

Credits
Discovery is credited to Martijn de Vries and Thomas de Klerk of Info Support.


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Disclaimer
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