Particularly the third vulnerability described in bulletin
MS03-043
can be classified as critical. It is highly recommended to
install all available security patches.
Bulletin
MS03-041 describes a vulnerability in Authenticode, under
certain low memory conditions, that could allow an unauthorized
ActiveX control to download, install, and execute without prompting
the user for approval.
An attacker may be able to exploit this vulnerability by hosting a
malicious Web Site which is designed to exploit this vulnerability.
If a user is visiting that site an ActiveX control could be
installed and executed on the user's system. Furthermore, an
attacker could also create a specially prepared HTML email message
and send it to the user. If the user viewed the message an
unauthorized ActiveX control could be installed and executed on the
user's system.
Bulletin
MS03-042 describes a buffer overflow vulnerability
in the Local Troubleshooter ActiveX control. If a user
viewed a specially prepared HTML e-mail message or page, which
embeds this control, an attacker could trigger a buffer overrun to
exploit this vulnerability and execute arbitrary code on the user's
system with the user's privileges.
Bulletin
MS03-043 describes a vulnerability in the Messenger
Service that could allow execution of arbitrary code on an
affected system. When processing a message the Messenger Service
does not properly validate the length of the message before passing
it to the allocated buffer. An attacker who exploited this
vulnerability could run code with Local System privileges on an
affected system, ord cause the Messenger Service
to fail. The attacker then could take arbitrary actions on the
system, including the installion of programs, viewing, changing or
deleting data, or creating new accounts with full privileges.
Bulletin
MS03-044 describes a buffer overflow vulnerability in the
Help and Support Center of Windows XP and Windows
2003 Server. If a user clicks on a specially crafted URL an attacker
could execute code of his choice in the Local Computer security
context. The URL could be hosted on a web page, or sent to the user
in an email message.
Bulletin
MS03-045 describes a buffer overflow vulnerability in a
API call of User32.dll-library. This Library is
called by ListBox and
ComboBox controls. An attacker who is able to
log on to a system interactively could run a program that sends a
specially-crafted Windows message to any applications that have
implemented theListBox and
ComboBox control, causing the application to
execute any action an attacker specifies. Exploiting this
vulnerability can be used by an attacker to gain complete control
over the system by using the Utility Manager in
Windows 2000.