MS releases grand daughter of all IE security patches

[InfoSec News <isn () c4i org>]

http://www.theregister.co.uk/content/6/25307.html

By John Leyden
Posted: 16/05/2002 at 14:50 GMT

Microsoft released another cumulative patch for Internet Explorer 
yesterday, which promises to plug up six recently discovered security 
defects involving the browser. 

The patch, for IE 5.01, 5.5 and 6.0, includes the functionality of 
previously released fixes, as well as tackling the new problems - the 
most serious of which could allow an attacker to run code of his 
choice on a victim's machine. Microsoft describes the patch as 
'critical', so let's hope it works properly. 

Six of the worst 

The most serious bug involves a cross-site scripting vulnerability. IE 
ships with several files that contain HTML on the local file system, 
one of which contains a flaw that could allow a script to execute as 
if it were run by the user. This bug could be exploited by an attacker 
who tricks victims into either visiting a maliciously constructed Web 
page or opening HTML email containing a poisoned script. 

Next up us is an information disclosure vulnerability related to a 
buggy HTML object, which is designed to provide support for Cascading 
Style Sheets. Because of the bug, an attacker might be able to read, 
but not delete or change, data on a local system, MS says. 

Moving on, there's an information disclosure vulnerability involving 
to the handling of script within cookies, which could potentially 
allow one site to read the cookies of another. 

Then there's a zone spoofing vulnerability that could allow a Web page 
to be incorrectly reckoned to be in the Intranet zone or, in some very 
rare cases, in the Trusted Sites zone. 

Finally there are two variants of a 'content disposition' 
vulnerability, which relate to how IE handles downloads when a 
downloadable file's Content-Disposition and Content-Type headers are 
intentionally malformed. Virus writers might use the technique to 
disguise the fact that an attachment contains executable content, 
hence the need for the patch. 

As well as plugging up the six vulnerabilities listed above, 
Microsoft's patch also disables frames in the Restricted Sites zone. 
The change means that recently released MS email clients (and those 
with Outlook Email Security Update installed) will disable frames in 
HTML email by default, blocking the possibility of an HTML email 
automatically opening a new window or launching the download of an 
executable. At least that's the idea. 

You could read about the problems in more details, and get links to 
the relevant patch, in Microsoft's advisory on the subject. 

http://www.microsoft.com/technet/treeview/default.asp?url=/technet/security/bulletin/MS02-023.asp



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