Microsoft Proxy Server 2.0 and Microsoft Internet Security and Acceleration (ISA) Server 2000 contain support for Windows Sockets (Winsock) proxy communications. Winsock is an API that handles communications requests for Internet applications in a Microsoft Windows operating system.
The Winsock proxy service works with FTP, Telnet, mail, news, Internet Relay Chat (IRC), and other client applications that are compatible with Winsock. The proxy service makes these applications perform as if they were directly connected to the Internet. The service redirects the necessary communications functions to a computer that is running either Proxy Server 2.0 or ISA Server. This establishes a communication path from the internal application to the Internet.
A flaw in the Winsock proxy service may permit an attacker on the internal network to send a specially crafted packet that results in 100% CPU utilization of the computer that is running either Proxy Server 2.0 or ISA Server, causing the computer to stop responding to internal and external requests.
The following files are available for download from the Microsoft Download Center:
ISA Server (all languages)Download the 331066 package now.
Proxy ServerDownload the 331066 package now.
Release Date: April 9, 2003
For additional information about how to download Microsoft Support files, click the following article number to view the article in the Microsoft Knowledge Base:
How to Obtain Microsoft Support Files from Online Services
Microsoft scanned this file for viruses. Microsoft used the most current virus-detection software that was available on the date that the file was posted. The file is stored on security-enhanced servers that help to prevent any unauthorized changes to the file.
This patch requires ISA Server Service Pack 1 (SP1). Microsoft will supply one version for each of five languages (English, German, French, Spanish, and Japanese).
For additional information about how to obtain the latest ISA Server service pack, click the following article number to view the article in the Microsoft Knowledge Base:
How to Obtain the Latest Internet Security and Acceleration Server Service Pack
Proxy Server 2.0
The Proxy Server 2.0 update requires Proxy Server 2.0 Service Pack 1 (SP1), and is the same for all languages.
For additional information about how to obtain the latest Proxy Server service pack, visit the following Microsoft Web site:
The ISA Server update supports the following Setup switches:
- /? : Display the list of installation switches.
- -q : Use Quiet mode (no user interaction).
- -USP : Remove the latest service pack.
- -UHFX : Remove hotfix number X (where X is the number of the hotfix) .
For example, to install the ISA Server update without user intervention, use the following command line:
To verify the ISA Server update is installed on your computer, confirm that the following registry key exists:
To verify the Proxy Server update is installed on your computer, confirm that the following registry key exists:
The ISA Server update does not require a restart, but the Proxy Server 2.0 update does require a restart.
You can remove the ISA Server update by using the Add/Remove Programs tool in Control Panel. Select Microsoft ISA Server 2000 Updates
, and then click Add/Remove
You can also remove this update by typing the following line at a command prompt:
You can remove the Proxy 2.0 server update by using the Add/Remove Programs tool in the Control Panel. Select Hotfix for Q331066
, and then click Add/Remove
Hotfix Replacement Information
This update does not replace any other updates.
The English version of this fix has the file attributes (or later) that are listed in the following table. The dates and times for these files are listed in coordinated universal time (UTC). When you view the file information, it is converted to local time. To find the difference between UTC and local time, use the Time Zone
tab in the Date and Time tool in Control Panel.
Microsoft Internet Security and Acceleration Server 2000
Date Time Version Size File name ------------------------------------------------------- 20-Mar-2003 14:56 3.0.1200.257 178,448 Mspadmin.exe 20-Mar-2003 14:55 3.0.1200.257 101,136 Msphlpr.dll 20-Mar-2003 14:55 3.0.1200.257 391,440 W3proxy.exe 20-Mar-2003 14:55 3.0.1200.257 298,768 Wspsrv.exe
Microsoft Proxy Server 2.0
Date Time Version Size File name ----------------------------------------------------- 26-Mar-2003 11:17 2.0.390.16 43,280 W3pcache.dll 26-Mar-2003 11:17 2.0.390.16 192,784 W3proxy.dll 26-Mar-2003 11:17 2.0.390.16 97,040 Wspsrv.exe
Microsoft has confirmed that this problem may cause a degree of security vulnerability in the Microsoft products that are listed at the beginning of this article.