TITLE : Microsoft Virtual Machine Bytecode Verifier Vulnerability

CRITICAL : Highly critical

IMPACT : System access

OPERATING SYSTEM:

Microsoft Windows 95

Microsoft Windows 98 and 98SE

Microsoft Windows Millennium

Microsoft Windows NT 4.0, beginning with Service Pack 1

Microsoft Windows 2000

Microsoft Windows XP

DESCRIPTION:

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A vulnerability identified in Microsoft VM (Virtual Machine) shipped

with almost all versions of Windows (except some versions of Windows

XP) can be exploited by malicious people to compromise a user's

system.

The vulnerability is caused by an input validation error in the

ByteCode Verifier, since it doesn't check for certain malicious

sequences of byte codes when loading Java applets. This can be

exploited by crafting a special Java applet and include it in web

page, which can either be hosted on a website or sent directly to a

user in an email.

When a user on a vulnerable system views the malicious web page, the

Java applet will be able to execute arbitrary code on the user's

system with the user's privileges.

In the email scenario, the vulnerability can be exploited

automatically to execute arbitrary code on the user's system when the

malicious email is viewed. However, this is not possible if the user

is viewing the malicious email in Outlook Express 6.0 or Outlook 2002

in their default configurations, or Outlook 98 or Outlook 2000 in

conjunction with the Outlook Email Security Update.

To check the version number of the installed Microsoft VM:

1) Type "Jview" at the command line.

2) Look at the four last digits of the version number at the topmost

line.

SOLUTION: Update Microsoft VM to version 3810 or later.

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http://www.microsoft.com/technet/security/bulletin/MS03-011.asp

http://windowsupdate.microsoft.com/

http://www.k-otik.com

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