Summary:
- This vulnerability affects: All current versions of Internet Explorer, running on all current versions of Windows
- How an attacker exploits it: Usually, by enticing one of your users to visit a malicious web page
- Impact: Various, in the worst case an attacker can execute code on your user’s computer, potentially gaining complete control of it
- What to do: Deploy the appropriate Internet Explorer patches immediately, or let Windows Automatic Update do it for you
Exposure:
In a security bulletin released today as part of Patch Day, Microsoft describes ten new vulnerabilities in Internet Explorer (IE) 8.0 and earlier versions, running on all current versions of Windows (including Windows 7 and Windows Server 2008). Microsoft rates the aggregate severity of these new flaws as Critical.
The ten vulnerabilities differ technically, but four of the most serious ones share the same general scope and impact. These four issues involve various memory corruption flaws having to do with how IE handles certain HTML elements and objects. If an attacker can lure one of your users to a web page containing malicious web code, he could exploit any one of these four vulnerabilities to execute code on that user’s computer, inheriting that user’s privileges. Typically, Windows users have local administrative privileges. In that case, the attacker could exploit these flaws to gain complete control of the victim’s computer.
The remaining vulnerabilities consists of Cross-Site or Cross-Domain Scripting (XSS) flaws and some Information Disclosure issues.
Keep in mind, today’s attackers often hijack legitimate web pages and booby-trap them with malicious code. Typically, they do this via hosted web ads or through SQL injection and XSS attacks. Even recognizable and authentic websites could pose a risk to your users if hijacked in this way.
If you’d like to know more about the technical differences between these flaws, see the “Vulnerability Information” section of Microsoft’s bulletin. Technical differences aside, the memory corruption flaws in IE pose significant risk. You should download and install the IE cumulative patch immediately.
Solution Path:
These patches fix serious issues. You should download, test, and deploy the appropriate IE patches immediately, or let Windows Automatic Update do it for you. By the way, Microsoft no longer supports Windows 2000 and IE 5.x. If you still run a legacy version of IE or Windows, we highly recommend you update in order to get the latest security updates.
- Internet Explorer 6.0
- Internet Explorer 7.0
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- For Windows XP (w/SP3)
- For Windows XP x64 (w/SP2)
- For Windows Server 2003 (w/SP2)
- For Windows Server 2003 x64 (w/SP2)
- For Windows Server 2003 Itanium (w/SP2)
- For Windows Vista (w/SP1 or SP2)
- For Windows Vista x64 (w/SP1 or SP2)
- For Windows Server 2008 (w/SP2) *
- For Windows Server 2008 x64 (w/SP2) *
- For Windows Server 2008 Itanium (w/SP2)
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- Internet Explorer 8.0
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- For Windows XP (w/SP3)
- For Windows XP x64 (w/SP2)
- For Windows Server 2003 (w/SP2)
- For Windows Server 2003 x64 (w/SP2)
- For Windows Vista (w/SP1 or SP2)
- For Windows Vista x64 (w/SP1 or SP2)
- For Windows Server 2008 (w/SP2) *
- For Windows Server 2008 x64 (w/SP2) *
- For Windows 7
- For Windows 7 x64
- For Windows Server 2008
- For Windows Server 2008 x64
-
* Note: These flaws do not affect Windows Server 2008 administrators who installed using the Server Core installation option.
Does My Firewall Help?
These attacks travel as normal-looking HTTP traffic, which you must allow if your network users need to access the World Wide Web. Therefore, the patches above are your best solution.
Status:
Microsoft has released patches to fix these vulnerabilities.
References:
This alert was researched and written by Corey Nachreiner, CISSP.