Flaw in Microsoft VM Could Enable System Compromise

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:

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.

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