Some media sources are quoting it as a ‘new bug‘ – which it isn’t, according to other sources it has been known about for at least 2 years and one paper has traced it back as far as 2002 (PDF file).

Microsoft last Friday said it was looking into a long-known vulnerability in Internet Explorer (IE) that could be used to access users’ data and Web-based accounts.

The bug can allow hackers to hijack Web mail accounts, steal data and send illicit tweets, said Google security engineer Chris Evans in a message posted on the Full Disclosure mailing list. Evans also published a demonstration that showed how the flaw in IE8 could be used to commandeer a user’s Twitter account and send unauthorized tweets.

The vulnerability, known as a “CSS cross-origin theft” bug, has a long history. Researchers at Carnegie Mellon University, who recently published a paper on the subject, have traced it back as far as 2002. Those researchers will present their paper at the Conference on Computer and Communications Security next month. Even so, the flaw received little attention until Evans blogged about it in December 2009. He had submitted a bug report for Chrome eight months earlier.

Microsoft did Tweet about looking into something but haven’t named it although coincidentally it was just a few hours after the public disclosure of this flaw. A point of contention is that this bug has been known about for a long time and has been patched by all the other major browsers including Chrome and Firefox.

Another interesting point is that Chris Evans is actually a Google engineer. Earlier this year Tavis Ormandy went public with a serious flaw in Windows once again stating Microsoft was unwilling to address it.

Although Microsoft has not patched the vulnerability in IE8, other browsers, including Firefox, Chrome, Safari and Opera, have fixed the flaw. Google patched the bug in Chrome last January, while Mozilla did the same in July with Firefox 3.6.7 and Firefox 3.5.11.

IE9 includes a fix for the vulnerability. Microsoft plans to ship a public beta of IE9 on Sept. 15.

On Friday, Evans explained why he was adding to the patch pressure by crafting a proof-of-concept. “I have been unsuccessful in persuading the vendor to issue a fix,” he said of Microsoft.

Microsoft issued a statement Friday saying it was investigating Evans’ reports, but declined to answer questions on Monday, including whether earlier versions of IE were vulnerable or why it has not yet addressed the bug.

“We’re currently unaware of any attacks trying to use the claimed vulnerability or of customer impact,” said Jerry Bryant, a group manager with the Microsoft Security Response Center, in the e-mailed statement.

In the case of Tavis Ormandy it was the Windows Help Vulnerability Exploited In The Wild, I expect with this vulnerability going public and with an accompanying proof of concept we may well see this CSS attack in the wild too.

IF you are interested you can see the PoC for the bug here:

http://scary.beasts.org/misc/twitter.html

Source: Network World

Internet Storm Center’s always informative Diary has some good information.

At the urging of Handler Extraordinaire Kyle Haugsness, I tested the sploit on a box with software-based DEP and DropMyRights… here are the results:

Software-based DEP protecting core Windows programs: sploit worked
Software-based DEP protecting all programs: sploit worked
DropMyRights, config’ed to allow IE to run (weakest form of DropMyRights protection): sploit worked
Active Scripting Disabled: sploit failed

So, go with the last one, if you are concerned. By the way, you should be concerned.

It didn’t take long for the exploits to appear for that IE vulnerability. One has been making the rounds that pops the calculator up (no, I’m not going to point you to the PoC code, it is easy enough to find if you read any of the standard mailing lists), but it is a relatively trivial mod to turn that into something more destructive. For that reason, SANS is raising Infocon to yellow for the next 24 hours.

Microsoft recommends you turn Active Scripting OFF to protect against this vulnerability.

Source: ISC

Yah I know, yet another reason to dump Internet Explorer and grab Firefox, not that anyone reading this site would be using Internet Exploder..

The code is along the lines of:

<code><input type=”checkbox” id=’c'>
<script>
r=document.getElementById(“c”);
a=r.createTextRange();
</script></code>

You can find the Bleeding Snort rule for the IE Exploit here.

Microsoft has now confirmed this.

“We’re still investigating, but we have confirmed this vulnerability and I am writing a Microsoft Security Advisory on this,” writes Lennart Wistrand, security program manager with the Microsoft Security Response Center, in a blog posting. “We will address it in a security update.”

There is also a 3rd party fix for this from eEye.