Alert: Microsoft Security Bulletin - MS03-008

From: Russ (Russ.Cooper@RC.ON.CA)
Date: 03/19/03

  • Next message: Russ: "Revised: Microsoft Security Bulletin - MS03-007"
    Date:         Wed, 19 Mar 2003 14:38:36 -0500
    From: Russ <Russ.Cooper@RC.ON.CA>

    Flaw in Windows Script Engine Could Allow Code Execution (814078)

    Originally posted: March 19, 2003


    Who should read this bulletin: Customers using Microsoft® Windows®.

    Impact of vulnerability: Run Code of Attacker's Choice

    Maximum Severity Rating: Critical

    Recommendation: Customers should install the patch immediately.

    End User Bulletin: An end user version of this bulletin is available at:

    Affected Software:
    - Microsoft Windows 98
    - Microsoft Windows 98 Second Edition
    - Microsoft Windows Me
    - Microsoft Windows NT 4.0
    - Microsoft Windows NT 4.0 Terminal Server Edition
    - Microsoft Windows 2000
    - Microsoft Windows XP

    Technical description:

    The Windows Script Engine provides Windows operating systems with the ability to execute script code. Script code can be used to add functionality to web pages, or to automate tasks within the operating system or within a program. Script code can be written in several different scripting languages, such as Visual Basic Script, or JScript.

    A flaw exists in the way by which the Windows Script Engine for JScript processes information. An attacker could exploit the vulnerability by constructing a web page that, when visited by the user, would execute code of the attacker's choice with the user's privileges. The web page could be hosted on a web site, or sent directly to the user in email.

    Although Microsoft has supplied a patch for this vulnerability and recommends all affected customers install the patch immediately, additional preventive measures have been provided that customers can use to help block the exploitation of this vulnerability while they are assessing the impact and compatibility of the patch. These temporary workarounds are discussed in the "Workarounds" section in the FAQ below.

    Mitigating factors:
    - For an attack to be successful, the user would need to visit a website under the attacker's control or receive an HTML e-mail from the attacker.
    - Computers configured to disable active scripting in Internet Explorer are not susceptible to this issue.
    - Exploiting the vulnerability would allow the attacker only the same privileges as the user. Users whose accounts are configured to have few privileges on the system would be at less risk than ones who operate with administrative privileges.
    - Automatic exploitation of the vulnerability by an HTML email would be blocked by Outlook Express 6.0 and Outlook 2002 in their default configurations, and by Outlook 98 and 2000 if used in conjunction with the Outlook Email Security Update.

    Vulnerability identifier: CAN-2003-0010

    This email is sent to NTBugtraq automatically as a service to my subscribers. (v1.18)

    Russ - Surgeon General of TruSecure Corporation/NTBugtraq Editor

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