MS01-051: Patch Available for HTTP Request Encoding Vulnerability

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Article ID: 308414 - View products that this article applies to.
This article was previously published under Q308414
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SYMPTOMS

A vulnerability exists in Internet Explorer 5.01, 5.5, and 6 that could enable an attacker to send you to a third-party site and include commands that, to the third-party site, would appear to have come from you. The precise actions that could be taken by using these commands would vary from site to site, but one example of a potential action would be to send you to your Web-based mail service with a command to delete your mail.

It is unlikely that this vulnerability could be used in any widespread attack because exploiting this vulnerability would require detailed knowledge of the Web services that you use, and would likely require information that was specific to you. However, it could be damaging if targeted against a selected person.

CAUSE

This vulnerability exists because it is possible to create a Web address (also known as a Uniform Resource Locator, or URL) that specifies the domain name of a third-party site and a series of HTTP requests. Upon processing such an URL, Internet Explorer would establish a connection with the third-party site, and then send the commands as though they had originated from you.

RESOLUTION

Internet Explorer 6

To resolve this problem, obtain the latest service pack for Windows XP. For additional information, click the following article number to view the article in the Microsoft Knowledge Base:
322389 How to Obtain the Latest Windows XP Service Pack
A supported fix is now available from Microsoft, but it is only intended to correct the problem that is described in this article. Apply it only to computers that you determine are at risk of attack. Evaluate your computer's physical accessibility, network and Internet connectivity, and other factors to determine the degree of risk to your computer. See the associated Microsoft Security Bulletin to help determine the degree of risk. This fix may receive additional testing. If your computer is sufficiently at risk, Microsoft recommends that you apply this fix now. Otherwise, wait for the next Internet Explorer 6 service pack that contains this fix.

To resolve this problem immediately, download the fix by following the instructions later in this article or contact Microsoft Product Support Services to obtain the fix. For a complete list of Microsoft Product Support Services phone numbers and information about support costs, visit the following Microsoft Web site:
http://support.microsoft.com/default.aspx?scid=fh;EN-US;CNTACTMS
NOTE: In special cases, charges that are ordinarily incurred for support calls may be canceled if a Microsoft Support Professional determines that a specific update will resolve your problem. The usual support costs will apply to additional support questions and issues that do not qualify for the specific update in question.

The "Security Update, December 13, 2001" patch is superseded by the following patch:
316059 MS02-005: February 11, 2002, Cumulative Patch for Internet Explorer
The "Security Update, December 13, 2001" patch is available at the following Microsoft Web site:
http://www.microsoft.com/windows/ie/downloads/critical/q313675/default.asp

Internet Explorer 5.5

A supported fix is now available from Microsoft, but it is only intended to correct the problem that is described in this article. Apply it only to computers that you determine are at risk of attack. Evaluate your computer's physical accessibility, network and Internet connectivity, and other factors to determine the degree of risk to your computer. See the associated Microsoft Security Bulletin to help determine the degree of risk. This fix may receive additional testing. If your computer is sufficiently at risk, Microsoft recommends that you apply this fix now. Otherwise, wait for the next Internet Explorer 5.5 service pack that contains this fix.

To resolve this problem immediately, download the fix by following the instructions later in this article or contact Microsoft Product Support Services to obtain the fix. For a complete list of Microsoft Product Support Services phone numbers and information about support costs, visit the following Microsoft Web site:
http://support.microsoft.com/default.aspx?scid=fh;EN-US;CNTACTMS
NOTE: In special cases, charges that are ordinarily incurred for support calls may be canceled if a Microsoft Support Professional determines that a specific update will resolve your problem. The usual support costs will apply to additional support questions and issues that do not qualify for the specific update in question.

The "Security Update, December 13, 2001" patch is superseded by the following patch:
316059 MS02-005: February 11, 2002, Cumulative Patch for Internet Explorer
The "Security Update, December 13, 2001" patch is available at the following Microsoft Web site:
http://www.microsoft.com/windows/ie/downloads/critical/q313675/default.asp

Internet Explorer 5.01

A supported fix is now available from Microsoft, but it is only intended to correct the problem that is described in this article. Apply it only to computers that you determine are at risk of attack. Evaluate your computer's physical accessibility, network and Internet connectivity, and other factors to determine the degree of risk to your computer. See the associated Microsoft Security Bulletin to help determine the degree of risk. This fix may receive additional testing. If your computer is sufficiently at risk, Microsoft recommends that you apply this fix now. Otherwise, wait for the next Internet Explorer 5.01 service pack that contains this fix.

To resolve this problem immediately, download the fix by following the instructions later in this article or contact Microsoft Product Support Services to obtain the fix. For a complete list of Microsoft Product Support Services phone numbers and information about support costs, visit the following Microsoft Web site:
http://support.microsoft.com/default.aspx?scid=fh;EN-US;CNTACTMS
NOTE: In special cases, charges that are ordinarily incurred for support calls may be canceled if a Microsoft Support Professional determines that a specific update will resolve your problem. The usual support costs will apply to additional support questions and issues that do not qualify for the specific update in question.

The "Security Update, October 10, 2001" patch is superseded by the following patches:
316059 MS02-005: February 11, 2002, Cumulative Patch for Internet Explorer
311401 Windows 2000 Security Rollup Package 1 (SRP1), January 2002
The "Security Update, October 10, 2001" patch is available at the following Microsoft Web site:
http://www.microsoft.com/downloads/results.aspx?pocId=&freetext=306121&DisplayLang=en

Internet Explorer 5.01 for Windows 2000

To resolve this problem, obtain the latest service pack for Internet Explorer 5.01 for Windows 2000. For additional information, click the following article number to view the article in the Microsoft Knowledge Base:
267954 How to Obtain the Latest Internet Explorer 5.01 Service Pack

STATUS

Internet Explorer 6

Microsoft has confirmed that this problem may cause a degree of security vulnerability in Internet Explorer 6. This problem was first corrected in Windows XP Service Pack 1.

Internet Explorer 5.5

Microsoft has confirmed that this problem may cause a degree of security vulnerability in Internet Explorer 5.5.

Internet Explorer 5.01

Microsoft has confirmed that this problem may cause a degree of security vulnerability in Internet Explorer 5.01. This problem was first corrected in Internet Explorer 5.01 for Windows 2000 Service Pack 3.Microsoft has confirmed that this is a problem in the Microsoft products that are listed at the beginning of this article. This problem was first corrected in Windows XP Service Pack 1.

MORE INFORMATION

For more information about this vulnerability, see the following Microsoft Web site:
http://www.microsoft.com/technet/security/bulletin/ms01-051.mspx

Properties

Article ID: 308414 - Last Review: February 27, 2014 - Revision: 5.3
APPLIES TO
  • Microsoft Internet Explorer 5.5 Service Pack 1
  • Microsoft Internet Explorer 5.5 Service Pack 2
  • Microsoft Internet Explorer 5.01
  • Microsoft Internet Explorer 5.01
  • Microsoft Internet Explorer 5.5 Service Pack 1
  • Microsoft Internet Explorer 5.5 Service Pack 2
  • Microsoft Internet Explorer 5.5 Service Pack 1
  • Microsoft Internet Explorer 5.5 Service Pack 2
  • Microsoft Internet Explorer 5.01
  • Microsoft Internet Explorer 5.01
  • Microsoft Internet Explorer 5.5 Service Pack 1
  • Microsoft Internet Explorer 5.5 Service Pack 2
  • Microsoft Internet Explorer 5.01
  • Microsoft Internet Explorer 5.01
  • Microsoft Internet Explorer 5.5
  • Microsoft Internet Explorer 5.5
  • Microsoft Internet Explorer 5.01
  • Microsoft Internet Explorer 5.01
  • Microsoft Internet Explorer 5.5 Service Pack 1
  • Microsoft Internet Explorer 5.5 Service Pack 2
  • Microsoft Internet Explorer 5.01
  • Microsoft Internet Explorer 5.01
  • Microsoft Internet Explorer 6.0, when used with:
    • Microsoft Windows XP Home Edition
    • Microsoft Windows XP Professional
    • Microsoft Windows XP Media Center Edition
    • Microsoft Windows XP Tablet PC Edition
    • Microsoft Windows 2000 Advanced Server
    • Microsoft Windows 2000 Datacenter Server
    • Microsoft Windows 2000 Professional Edition
    • Microsoft Windows 2000 Server
    • Microsoft Windows NT Server 4.0 Standard Edition
    • Microsoft Windows NT Server 4.0, Terminal Server Edition
    • Microsoft Windows NT Workstation 4.0 Developer Edition
    • Microsoft Windows 98 Second Edition
    • Microsoft Windows 98 Standard Edition
Keywords: 
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