Security design: Why UAC will not work

Pinning all your end-point security hopes on UAC assumes that criminals are not as smart as they really are

It's security's dirty little secret: Not having your users logged in as root or administrator will not stop malware.

There is a huge public security thrust to ensure that users are not constantly logged on with highly privileged access. In Microsoft Windows, this means not being logged in as a member of the administrators group or any of the other 17 groups with admin-like privileges (for example, Power Users). In Unix/Linux/BSD, this means not being logged in as root or bin or whatever else is close. In the AS/400, it means not being logged in as Qsysop or Qsecofr. For mainframes, it might mean superuser, terminal 0, or another user label indicating special privileges.

Unfortunately, the concept of least privilege is more a popular mantra than a rule in most environments. This is especially true at home, but it's nearly as bad at work. If you want to find someone logged in as administrator or root all the time, point your finger in the general direction of network security folks: "Do as I say, not as I do."

Microsoft is trying to encourage users and developers to go least privilege by introducing UAC (User Account Control) in Windows Vista, and the Unix/Linux/BSD folks have being trying for a decade longer with Switch User (SU).

No panacea

The problem is that even if no one ever logged in as a superuser, it wouldn't make a dent in the ability of malware writers to do bad things to us and our computers.

It would stop a lot of the current malware, but only because they are designed (like a lot of today's legitimate software) to expect the user running it to be logged on as privileged. And in most cases, this is a good assumption. Most users are logged in using privileged accounts, but malware doesn't need privileged access to do bad things.

Even today, there are hundreds of malware programs that can do all the nasty things they want: modify your computer, steal your identity, whatever, without ever needing admin or root access.

Forget for the moment remote buffer overflows, social engineering, phishing, and all the other sorts of maliciousness that don't care about your logon credentials; malware doesn't need to modify your system files to cause problems.

On location

It's always been a mystery to me why Windows malware tries so hard to modify files or place itself in the System32 directory. Most people say it's because the malware wants to modify the Windows OS, and that's true. But the System32 directory location isn't needed. I've been keeping a table of all the ways and places that Windows malware can locate itself to cause damage, and I have more than 130 entries. My Linux/Unix/BSD list is much smaller, but contains a few dozen locations. Many of the listings on both documents do not require admin or root access to manipulate.

For example, most Windows malware modifies the HKey\Local_Machine\Software\Microsoft\Windows\Run registry key, but I have dozens of other keys that can be modified to launch just as easily. For instance, malware can use the user's own registry profile keys instead. Users always have Full Control to their own profile's auto-run registry keys, and they are checked (and the listed programs launched) by the computer after executing code in the machine's startup areas.

Let me be more explicit: There is nothing that malware can do today that can't be done without privileged access. I'm not talking about the way they can modify the system, but the intended result of the modification. Malicious hackers may not be able to modify System32 or sbin, but they can still intercept your identity and steal all your money, without modifying your operating system or (in the case of memory-resident-only malware) a single file.

Join the newsletter!

Or

Sign up to gain exclusive access to email subscriptions, event invitations, competitions, giveaways, and much more.

Membership is free, and your security and privacy remain protected. View our privacy policy before signing up.

Error: Please check your email address.
Keep up with the latest tech news, reviews and previews by subscribing to the Good Gear Guide newsletter.
Roger A. Grimes

Roger A. Grimes

InfoWorld
Show Comments

Cool Tech

Toys for Boys

Family Friendly

Stocking Stuffer

SmartLens - Clip on Phone Camera Lens Set of 3

Learn more >

Christmas Gift Guide

Click for more ›

Brand Post

Most Popular Reviews

Latest Articles

Resources

PCW Evaluation Team

Aysha Strobbe

Microsoft Office 365/HP Spectre x360

Microsoft Office continues to make a student’s life that little bit easier by offering reliable, easy to use, time-saving functionality, while continuing to develop new features that further enhance what is already a formidable collection of applications

Michael Hargreaves

Microsoft Office 365/Dell XPS 15 2-in-1

I’d recommend a Dell XPS 15 2-in-1 and the new Windows 10 to anyone who needs to get serious work done (before you kick back on your couch with your favourite Netflix show.)

Maryellen Rose George

Brother PT-P750W

It’s useful for office tasks as well as pragmatic labelling of equipment and storage – just don’t get too excited and label everything in sight!

Cathy Giles

Brother MFC-L8900CDW

The Brother MFC-L8900CDW is an absolute stand out. I struggle to fault it.

Luke Hill

MSI GT75 TITAN

I need power and lots of it. As a Front End Web developer anything less just won’t cut it which is why the MSI GT75 is an outstanding laptop for me. It’s a sleek and futuristic looking, high quality, beast that has a touch of sci-fi flare about it.

Emily Tyson

MSI GE63 Raider

If you’re looking to invest in your next work horse laptop for work or home use, you can’t go wrong with the MSI GE63.

Featured Content

Product Launch Showcase

Don’t have an account? Sign up here

Don't have an account? Sign up now

Forgot password?