By Robert McMillan
JULY 12, 2005
IDG NEWS SERVICE
Microsoft Corp. has released three software updates that patch
critical security flaws in its products, including a patch for an
Internet Explorer vulnerability first reported last week. The company
also released patches for Microsoft Word and for a feature of the
Windows operating system used by a number of applications.
All three of the patches, which Microsoft calls "updates," are rated
"critical," meaning that the flaws they fix could allow malicious code
to be installed on a user's computer with very little user action. The
updates, released as part of the company's monthly security bulletin
, affect current versions of Windows and Internet Explorer as well
as some older versions of Word, according to Stephen Toulouse,
security program manager at Microsoft's security response center.
The Internet Explorer and Windows patches appear to be the most
significant, since the flaws they address could be used by an attacker
to take control of a user's system via a maliciously encoded Web page,
said Neel Mehta, team leader of X-Force research at security vendor
Internet Security Systems Inc. (ISS) in Atlanta. The Internet Explorer
bug is significant because security experts have already shown a way
that it could be exploited by an attacker, he said.
Last week, Microsoft issued a work-around to the problem, which
concerns a file used by Internet Explorer called Javaprxy.dll. Today's
patch fixes the underlying problem, Metha said.
ISS is also concerned about the Windows vulnerability, which relates
to a feature called the Microsoft Color Management Module. This
software is used to ensure that colors look the same when they are
being rendered on different types of hardware and is employed by a
number of widely used applications, including Microsoft Outlook and
Internet Explorer, Metha said.
"Our initial analysis shows it being pretty conducive to
exploitation," Metha said. "Any application that uses the built-in
Windows facilities to show JPEG images, or possibly some other images,
could be an attack vector for this vulnerability."
In fact, Microsoft has already privately been made aware of exploits
of this flaw, Toulouse said.
The Word vulnerability, which could allow an attacker to gain control
of a user's system when a maliciously encoded Word document is opened,
doesn't affect the most recent version of the word processor. However,
users of Word 2000 and 2002 will need to install the patch, Toulouse
The three patches are detailed in Microsoft Security Bulletins
MS05-35, MS05-36 and MS05-37. A new version of a previously released
bulletin entitled MS05-33 was also released after Microsoft discovered
that the Windows bug that it addresses also affects the company's
Services for Unix 2.0 and 2.1. products, Toulouse said.
All three of the patches will probably require a reboot in order to
take effect, Toulouse said. "If the files are in use when the update
is applied, and in these cases they're pretty much going to be, that
is what forces a reboot," he said.
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