11th Apr 2003 [SBWID-6137]
Microsoft Virtual Machine Bytecode Verifier Vulnerability
Microsoft Windows 9x, Me, NT, 2000, XP
K-Otik.com [http://www.k-otik.com] found following:
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
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.
Update Microsoft VM to version 3810 or later.