0wning Vista from the boot

A rootkit I've never seen before....Pretty scarry.

Federico Biancuzzi interviews Nitin and Vipin Kumar, authors of VBootkit, a rootkit that is able to load from Windows Vista boot-sectors. They discuss the "features" of their code, the support of the various versions of Vista, the possibility to place it inside the BIOS (it needs around 1500 bytes), and the chance to use it to bypass Vista's product activation or avoid DRM.

Could you introduce yourself?

Nitin Kumar: I am a 23 years old graduate from India. I am passionate about computers. The best part about me is that I never give up something till I give a try to it. I like coding in C and asm. I like Reverse Engineering. In free time I usually pick up something and try to understand that. Vista is new and have many new security features, so we thought of creating something for Vista.

Vipin Kumar: I am a 22 year old graduate from India. I like analysing OSes (mainly the internals , kernel stuff etc) and testing OS and network security. Our coding stuff includes development of bootkit, vbootkit and numerous shell-codes and lots of Windows stuff.

For money, we also go for vulnerability assesments, security audits, etc. Life is not easy for us, so we struggle/work a lot to have some hardware like many other guys out there. Feel free to contact us if you need us.

What is Vbootkit?

Nitin & Vipin: Vbootkit is much like a door or a shortcut to access vista's kernel.

A bootkit is a rootkit that is able to load from a boot-sectors (master boot record, CD , PXE , floppies etc) and persist in memory all the way through the transition to protected mode and the startup of the OS. It's a very interesting type of rootkit. All rootkits install when the OS is running because they use the OS' features to load (and also they use the Administrator privileges to install), but bootkits are different, they use the boot media to attack the OS , and thus survive. Vbootkit is a bootkit specific for Windows Vista.

It's a total in-Ram concept. So, it doesn't touch the hard-disk under any condition and thus leaves no proofs. Just give a reboot to a vbootkit running system, and it vanishes just as it was never here.

What "features" does it provide to Windows users?

Nitin & Vipin: At the moment, it doesn't really provide features to the users. It's just a Proof-of-Concept, that such an attack vector exists which can be used to circumvent the full security of the OS, without being easily traceable.

At the moment it can do a few things which are:

* It periodically raises cmd.exe's privilege to SYSTEM after every few seconds.
* Modify Registry so as to start the telnet server automatically
* Create a user mode thread and deliver the user mode payloads in context of a system(protected) process (LSASS.EXE, Winlogon.exe etc)

Basically, it can do ANYTHING what the user programs it to do, since vbootkit becomes part of the kernel, it can do anything that Vista's kernel can do.

Does it work on all the versions of Windows Vista?

Nitin & Vipin: Yes, It should work with almost all Vista releases, even localised ones, but it will need a little bit of fine tuning. Most probably, it will support Vista Pack 1, but hey this is only a guess.

Have you released your code online?

Nitin & Vipin: No, we haven't released the code for vbootkit, but we have provided binaries to a few antivirus vendors.

However, you can download previous versions of bootkit (which runs on Windows 2000/XP/2003) from the our site. Even source code is provided.

As far as demos are concerned, readers might be interested in the white paper [PDF], slides from our presentation [PPT], videos showing vbootkit in action [AVI1 - AVI2].

What was the antivirus vendors response?

Nitin & Vipin: Nowadays, many antivirus solutions don't scan for boot stuff.

I think for home users, this might not be much of a problem -- unless they regularly boot using media from suspicious sources.



In my case, I boot from GRUB directly into the Vista Loader, and then into the kernel, effectively bypassing both the MBR of the Vista volume and the vista boot manager.



But, that wouldn't protect me from loader or kernel corruption.



I would be more worried about this in the enterprise environment, where if a persistent version was developed, someone could walk around with a bootable CD and load the rootkit into one machine after another.