Severity: High
Summary:
- This vulnerability affects: All current versions of Internet Explorer, running on all current versions of Windows (to varying extents)
- How an attacker exploits it: 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, 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 four new vulnerabilities in Internet Explorer (IE) 9.0 and earlier versions, running on all current versions of Windows. Microsoft rates the aggregate severity of these new flaws as Critical.
The four vulnerabilities differ technically, but two of them share the same general scope and impact. These two issues involve memory corruption flaws related to the way IE mishandles various HTML objects. If an attacker can lure one of your users to a web page containing malicious web code, he could exploit either of these vulnerabilities to execute code on that user’s computer by inheriting that user’s privileges. Typically, Windows users have local administrative privileges, in which case the attacker gains complete control of your users’ computers.
This update also fixes two less severe information disclosure vulnerabilities, which you can read more about in Microsoft’s bulletin.
Today’s attackers commonly hijack legitimate web pages and booby-trap them with malicious code. Often, even recognizable and authentic websites get hijacked in this way, and are forced to deliver drive-by download attacks. To avoid these types of attacks, we recommend that you install Microsoft’s IE updates as quickly as you can.
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.
This link takes you directly to the “Affected and Non-Affected Software” section of Microsoft’s IE bulletin, where you can find links for the various IE updates.
For All WatchGuard Users:
These attacks travel as normal-looking HTTP traffic, which you must allow if your network users need to access the internet. Therefore, the patches above are your best solution.
Generally, our IPS, AV, and Reputation Enabled Defense (RED) services can help protect you against this class of attack.
Status:
Microsoft has released patches to fix these vulnerabilities.
References:
This alert was researched and written by Corey Nachreiner, CISSP (@SecAdept).