Hackers jump through holes in Microsoft patch

[InfoSec News <isn () c4i org>]

Forwarded from: William Knowles <wk () c4i org>

http://www.nwfusion.com/news/2003/0908hackejump.html

By Paul Roberts
IDG News Service
09/08/03

Security experts are warning Microsoft customers about silent Internet
attacks that exploit a security flaw in the Internet Explorer Web
browser, potentially allowing remote attackers to run malicious code
on vulnerable machines.

The vulnerability is similar in scope to those exploited by
devastating worms such as Nimda, Badtrans and Klez, according to one
security company. And, to make matters worse, the flaw is one
Microsoft said it fixed weeks ago.

The security hole, known as the "Object Data vulnerability," affects
Internet Explorer (IE) versions 5.01, 5.5 and 6.0. It concerns the way
that IE processes HTML pages containing a special element called the
Object Data tag. If properly exploited, the vulnerability could enable
an attacker to place a malicious computer program on a user's machine.  
No user actions would be required aside from opening an e-mail message
or visiting a Web page containing the attack.

On Aug.20, Microsoft released a patch for IE, MS03--032, that it said
closed the hole, in addition to patching other security holes in IE.

According to a message posted to a prominent security discussion group
Sunday, however, the vulnerability still exists on machines using IE
even after applying the patch.

That message, posted by an individual using the name
"http-equiv () excite com," contained sample code that showed IE is still
vulnerable to attack using the vulnerability from HTML pages that are
created dynamically using computer script, like JavaScript, embedded
in Web pages or e-mail messages.

A Microsoft spokesman confirmed that the company is investigating the
reports of new exploits for one of the vulnerabilities addressed in
the MS03-032 security bulletin.

However, Microsoft still recommends that customers install that patch,
he said.

The software giant is not aware of any customers who have been
attacked using the vulnerability, he said.

However, security researchers know of at least one exploitation of the
Object Data vulnerability that is already circulating on the Internet,
according to a statement by security company Secunia of Copenhagen,
Denmark.

An e-mail message that contains HTML code that exploits the
vulnerability is used to silently retrieve and run a file, "drg.exe,"  
that installs a file called "surferbar.dll" onto the victim's
computer, according to the Secunia alert.

That file adds a new bar to the affected users' Internet Explorer Web
browser with links to pornographic Web sites, the company said.

The Object Data vulnerability is also similar to an earlier IE
security hole dating to 2001, MS01-020, that was exploited by virulent
e-mail worms such as Nimda and Klez, according to Secunia.

Security experts familiar with the issue say that Microsoft's failure
to thoroughly test their patch against attack scenarios using the
Object Data vulnerability is a black eye for the company.

"Microsoft should be ashamed. This is a major embarrassment," said
Richard Smith, an independent security analyst based in Boston.

The problem with the Object Data vulnerability is similar to a hole
found in a prior Microsoft patch, according to Israeli security
company GreyMagic Software, which issued a report on the problem in
Feb. 2002.

That fact points to problems with Microsoft's patch testing process,
Smith said.

"They need to go back and look at how this slip-up occurred. They keep
saying they can't prevent bugs, but when the same problems keep
occurring over and over, that's a management issue," he said.

A Microsoft spokesman said the company is committed to keeping
customers data safe and will take "appropriate action" to protect
customers when its investigation into the new exploits is complete.

In the absence of a patch from Microsoft to fix the problem, security
experts recommended disabling support for Active Scripting on affected
IE versions. Failing that, users should consider uninstalling the
popular browser to protect themselves from attack, experts said.


 
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