Engineering Windows 7

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User Account Control

User Account Control

We promised that this blog would provide a view of Engineering Windows 7 and that means that we would cover the full range of topics—from performance to user interface, technical and non-technical topics, and of course easy topics and controversial topics.  This post is about User Account Control.  Our author is Ben Fathi, vice president for core OS development.  UAC is a feature that crosses many aspects of the Windows architecture—security, accounts, user interface, design, and so on—we had several other members of the team contribute to the post. 

We continue to value the discussion that the posts seem to inspire—we are betting (not literally of course) that this post will bring out comments from even the most reserved of our readers.  Let’s keep the comments constructive and on-topic for this one.

FWIW, the server employs some throttles on comments that aim to reduce spam.  We don’t control this and have all the “unmoderated” options checked.  I can’t publish the spam protection rules since that sort of defeats the purpose (and I don’t know them).  However, I apologize if your comment doesn’t make it through.  --Steven

User Account Control (UAC) is, arguably, one of the most controversial features in Windows Vista. Why did Microsoft add all those popups to Windows? Does it actually improve security? Doesn’t everyone just click “continue”? Has anyone in Redmond heard the feedback on users and reviewers? Has anyone seen a tv commercial about this feature? 

In the course of working on Windows 7 we have taken a hard look at UAC – examining customer feedback, volumes of data, the software ecosystem, and Windows itself. Let’s start by looking at why UAC came to be and our approach in Vista.

The Why of UAC

Technical details aside, UAC is really about informing you before any “system-level” change is made to your computer, thus enabling you to be in control of your system. An “unwanted change” can be malicious, such as a virus turning off the firewall or a rootkit stealthily taking over the machine. However an “unwanted change” can also be actions from people who have limited privileges, such as a child trying to bypass Parental Controls on the family computer or an employee installing prohibited software on a work computer. Windows NT has always supported multiple user account types – one of which is the “standard user,” which does not have the administrative privileges necessary to make changes like these. Enterprises can (and commonly do) supply most employees with a standard user account while providing a few IT pros administrative privileges. A standard user can’t make system level changes, even accidentally, by going to a malicious website or installing the wrong program. Controlling the changes most people can make to the computer reduces help desk calls and the overall Total Cost of Ownership (TCO) to the company. At home, a parent can create a standard user account for the children and use Parental Controls to protect them.

However, outside the enterprise and the Parental Controls case, most machines (75%) have a single account with full admin privileges. This is partly due to the first user account defaulting to administrator, since an administrator on the machine is required, and partly due to the fact that people want and expect to be in control of their computer. Since most users have an Administrator account, this has historically created an environment where most applications, as well as some Windows components, always assumed they could make system-level changes to the system. Software written this way would not work for standard users, such as the enterprise user and parental control cases mentioned above. Additionally, giving every application full access to the computer left the door open for damaging changes to the system, either intentionally (by malware) or unintentionally (by poorly written software.)

Percentage of machines (server excluded) with one or more user accounts from January 2008 to June 2008.  75% of machines have one account.

Figure 1. Percentage of machines (server excluded) with one or more user accounts from January 2008 to June 2008.

User Account Control was implemented in Vista to address two key issues: one, incompatibility of software across user types and two, the lack of user knowledge of system-level changes. We expanded the account types by adding the Protected Admin (PA), which became the default type for the first account on the system. When a PA user logs into the system, she is given two security tokens – one identical to the Standard User token that is sufficient for most basic privileges and a second with full Administrator privileges. Standard users receive only the basic token, but can bring in an Administrator token from another account if needed.

When the system detects that the user wants to perform an operation which requires administrative privileges, the display is switched to “secure desktop” mode, and the user is presented with a prompt asking for approval. The reason the display is transitioned to “secure desktop” is to avoid malicious software attacks that attempt to get you to click yes to the UAC prompt by mimicking the UAC interface (spoofing the UI.) They are not able to do this when the desktop is in its “secure” state. Protected Admin users are thus informed of any system changes, and only need to click yes to approve the action. A standard user sees a similar dialog, but one that enables her to enter Administrative credentials (via password, smart card PIN, fingerprint, etc) from another account to bring in the Administrator privileges needed to complete the action. In the case of a home system utilizing Parental Controls, the parent would enter his or her login name and password to install the software, thus enabling the parent to be in control of software added to the system or changes made to the system. In the enterprise case, the IT administrator can control the prompts through group policy such that the standard user just gets a message informing her that she cannot change system state.

What we have learned so far

We are always trying to improve Windows, especially in the areas that affect our customers the most. This section will look at the data around the ecosystem, Windows, and end-users—recognizing that the data itself does not tell the story of annoyance or frustration that many reading this post might feel. 

UAC has had a significant impact on the software ecosystem, Vista users, and Windows itself. As mentioned in previous posts, there are ways for our customers to voluntarily and anonymously send us data on how they use our features (Customer Experience Improvement Program, Windows Feedback Panel, user surveys, user in field testing, blog posts, and in house usability testing). The data and feedback we collect help inform and prioritize the decisions we make about our feature designs. From this data, we’ve learned a lot about UAC’s impact.

Impact on the software ecosystem

UAC has resulted in a radical reduction in the number of applications that unnecessarily require admin privileges, which is something we think improves the overall quality of software and reduces the risks inherent in software on a machine which requires full administrative access to the system.

In the first several months after Vista was available for use, people were experiencing a UAC prompt in 50% of their “sessions” - a session is everything that happens from logon to logoff or within 24 hours. Furthermore, there were 775,312 unique applications (note: this shows the volume of unique software that Windows supports!) producing prompts (note that installers and the application itself are not counted as the same program.) This seems large, and it is since much of the software ecosystem unnecessarily required admin privileges to run. As the ecosystem has updated their software, far fewer applications are requiring admin privileges. Customer Experience Improvement Program data from August 2008 indicates the number of applications and tasks generating a prompt has declined from 775,312 to 168,149.

Number of unique applications and tasks creating UAC prompts.  Shows a significant decline.

Figure 2. Number of unique applications and tasks creating UAC prompts.

This reduction means more programs work well for Standard Users without prompting every time they run or accidentally changing an administrative or system setting. In addition, we also expect that as people use their machines longer they are installing new software or configuring Windows settings less frequently, which results in fewer prompts, or conversely when a machine is new that is when there is unusually high activity with respect to administrative needs. Customer Experience Improvement Program data indicates that the number of sessions with one or more UAC prompts has declined from 50% to 33% of sessions with Vista SP1.

Percentage of sessions with prompts over time. 

Figure 3. Percentage of sessions with prompts over time.

Impact on Windows

An immediate result of UAC was the increase in engineering quality of Windows. There are now far fewer Windows components with full access to the system. Additionally, all the components that still need to access the full system must ask the user for permission to do so. We know from our data that Windows itself accounts for about 40% of all UAC prompts. This is even more dramatic when you look at the most frequent prompts: Windows components accounted for 17 of the top 50 UAC prompts in Vista and 29 of the top 50 in Vista SP1. Some targeted improvements in Vista SP1 reduced Windows prompts from frequently used components such as the copy engine, but clearly we have more we can (and will) do. The ecosystem also worked hard to reduce their prompts, thus the number of Windows components on the top 50 list increased. Windows has more of an opportunity to make deeper architectural changes in Windows 7, so you can expect fewer prompts from Windows components. Reducing prompts in the software ecosystem and in Windows is a win-win proposition. It enables people to feel confident they have a greater choice of software that does not make potentially destabilizing changes to the system, and it enables people to more readily identify critical prompts, thus providing a more confident sense of control.

One important area of feedback we’ve heard a lot about is the number of prompts encountered during a download from Internet Explorer. This is a specific example of a more common situation - where an application’s security dialogs overlap with User Account Control. Since XP Service Pack 2, IE has used a security dialog to warn users before running programs from the internet. In Vista, this often results in a double prompt – IE’s security dialog, followed immediately by a UAC dialog. This is an area that should be properly addressed.

Number of Microsoft prompters in the top 50 over time.

Figure 4. Number of Microsoft prompters in the top 50 over time.

Impact on Customers

One extra click to do normal things like open the device manager, install software, or turn off your firewall is sometimes confusing and frustrating for our users. Here is a representative sample of the feedback we’ve received from the Windows Feedback Panel:

  • “I do not like to be continuously asked if I want to do what I just told the computer to do.”
  • “I feel like I am asked by Vista to approve every little thing that I do on my PC and I find it very aggravating.”
  • “The constant asking for input to make any changes is annoying. But it is good that it makes kids ask me for password for stuff they are trying to change.”
  • “Please work on simplifying the User Account control.....highly perplexing and bothersome at times”

We understand adding an extra click can be annoying, especially for users who are highly knowledgeable about what is happening with their system (or for people just trying to get work done). However, for most users, the potential benefit is that UAC forces malware or poorly written software to show itself and get your approval before it can potentially harm the system.

Does this make the system more secure? If every user of Windows were an expert that understands the cause/effect of all operations, the UAC prompt would make perfect sense and nothing malicious would slip through. The reality is that some people don’t read the prompts, and thus gain no benefit from them (and are just annoyed). In Vista, some power users have chosen to disable UAC – a setting that is admittedly hard to find. We don’t recommend you do this, but we understand you find value in the ability to turn UAC off. For the rest of you who try to figure out what is going on by reading the UAC prompt , there is the potential for a definite security benefit if you take the time to analyze each prompt and decide if it’s something you want to happen. However, we haven’t made things easy on you - the dialogs in Vista aren’t easy to decipher and are often not memorable. In one lab study we conducted, only 13% of participants could provide specific details about why they were seeing a UAC dialog in Vista.  Some didn’t remember they had seen a dialog at all when asked about it. Additionally, we are seeing consumer administrators approving 89% of prompts in Vista and 91% in SP1. We are obviously concerned users are responding out of habit due to the large number of prompts rather than focusing on the critical prompts and making confident decisions. Many would say this is entirely predictable.

Percentage of prompts over time per prompt type.

Figure 5. Percentage of prompts over time per prompt type.

Percentage of UAC prompts allowed over time.

Figure 6. Percentage of UAC prompts allowed over time.

Looking ahead…

Now that we have the data and feedback, we can look ahead at how UAC will evolve—we continue to feel the goal we have for UAC is a good one and so it is our job to find a solution that does not abandon this goal. UAC was created with the intention of putting you in control of your system, reducing cost of ownership over time, and improving the software ecosystem. What we’ve learned is that we only got part of the way there in Vista and some folks think we accomplished the opposite.

Based on what we’ve learned from our data and feedback we need to address several key issues in Windows 7:

  • Reduce unnecessary or duplicated prompts in Windows and the ecosystem, such that critical prompts can be more easily identified.
  • Enable our customers to be more confident that they are in control of their systems.
  • Make prompts informative such that people can make more confident choices.
  • Provide better and more obvious control over the mechanism.

The benefits UAC has provided to the ecosystem and Windows are clear; we need to continue that work. By successfully enabling standard users UAC has achieved its goal of giving IT administrators and parents greater control to lock down their systems for certain users. As shown in our data above, we’ve seen the number of external applications and Windows components that unnecessarily require Admin privileges dramatically drop. This also has the direct benefit of reducing the total amount of prompts users see, a common complaint we hear frequently. Moving forward we will look at the scenarios we think are most important for our users so we can ensure none of these scenarios include prompts that can be avoided. Additionally, we will look at “top prompters” and continue to engage with third-party software vendors and internal Microsoft teams to further reduce unnecessary prompts.

More importantly, as we evolve UAC for Windows 7 we will address the customer feedback and satisfaction issues with the prompts themselves. We’ve heard loud and clear that you are frustrated. You find the prompts too frequent, annoying, and confusing. We still want to provide you control over what changes can happen to your system, but we want to provide you a better overall experience. We believe this can be achieved by focusing on two key principles. 1) Broaden the control you have over the UAC notifications. We will continue to give you control over the changes made to your system, but in Windows 7, we will also provide options such that when you use the system as an administrator you can determine the range of notifications that you receive. 2) Provide additional and more relevant information in the user interface. We will improve the dialog UI so that you can better understand and make more informed choices. We’ve already run new design concepts based on this principle through our in-house usability testing and we’ve seen very positive results. 83% of participants could provide specific details about why they were seeing the dialog. Participants preferred the new concepts because they are “simple”, “highlight verified publishers,” “provide the file origin,” and “ask a meaningful question.” 

In summary, yes, we’ve heard the responses to the UAC feature – both positive and negative. We plan to continue to build on the benefits UAC provides as an agent for standard user, making systems more secure. In doing so, we will also address the overwhelming feedback that the user experience must improve.

Ben Fathi

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  • I work in computer forensics and UAC would make the kind of work we do unbearable. We're are holding onto our current XP licenses for dear life. Our toolbox for operating systems and software is vast and so is the range of data and hardware we need to be able to handle every day. Vista usability and UAC is just a hindrance at the moment.

    Despite that I've stuck my head above the parapet and installed Vista on a new forensic worksation, to looks of pity and disdain from my colleagues. And UAC is now off - no great surprise.

    The idea behind UAC is great and so is the positive effect it's apparently had on stamping out lazy programming. It just needs a complete usability overhaul - pointless to accuse users of being irreponsible by not paying any attention to the meaning behind an endless stream of uninformative UAC prompts. UAC-click fatigue really is a design failure, not a user defect.

    It would be illuminating to track the rate of UAC dialogs that occur during normal usage, for different profiles of computer user: home, corporate, hobbyist, developer, deep technical, admin etc, simply to quantify the level of disruption it can cause some people at the power user end of the spectrum. Many of our core forensic tools have a high "RSI index" which is outside of our control - UAC-induced RSI just makes it worse.

    It's been done to death by some great suggestions in this blog, but the *option* to use a whitelist, and/or an *option* for a training mode, would be fantastic. These options could be locked out in user environments where that flexibility is inappropriate.

    Administrators need to administer without hindrance and some of my *cough* relatives could do with a heavy handed UAC... and you have the vast gamut of users in between the two extremes. Deep down I like enough of Vista to give it and its successor a real chance in the workplace, but I am in a very small minority here. At some point we'll have to choose between upgrading to Windows 7 or running an alternative platform with emulators and virtual environments - that decision will be influenced by whatever lets us just get on and do our job.

  • Thank you for posting this information. I understand all your points, however, some applications (e.g., Adobe CS4 Premiere Pro) will just not start when the UAC is on.

    So, I had to turn it off.

    So, please, do not remove the capability for the user to turn UAC off (sometime it is the only solution to use a software)

  • Why not just ditch UAC altogether and focus more on integrating Symantec and Norton anti-virus programs into the OS?

    And make rollbacks 1-click painless.

    In your head, conceptually equate "malware" with "the possibility that someone will deface a Wikipedia article".  

    Both will always be there, like gravity.

    Frankly, if something gives me a virus, I'd rather just 1-click my way back to a point in time where I didn't have the virus.  That, instead of having to work under constant Q&A inspection.

  • User Account Control is not all about that. The article uses parental control as an example. Say the system of allowing the user to make changes was allowed and the rollback system was implemented...

    Protecting parental controls would become useless because they would then be easily bypassed becase they're allowed to edit them.

    Is it possible to have UAC implement a white list and an 'inclusions' function?

    So programs on the white list are always allowed and will not generate UAC prompts. The inclusions feature would allow a system administrator to add Windows functions and third party applications that require UAC confirmation before being allowed to continue? For example, trying to disable a third party application that's required to be running on any given system.

  • Mark Twain said there are three types of lies: 1) Lies, 2) D*** Lies, and 3) Statistics.

    I'm curious if the data reported about user experience and ecosystem changes is being interpretted correctly. For example, could the  user sessions with a UAC prompt and in the number of applications requiring one, instead, be due to users disabling UAC altogether, at least in part?

  • Great blog, thanks! so far windows 7 is very impressive! Luv ya work Microsoft Team! :)

  • Not at all shockingly, Linux has been handling UAC properly for years.  Even as a regular Linux user for several years and having grown quite accustomed to the nix version of UAC, the mindboggingly terrible way in which it was implemented in Vista literally made me spitting mad at times.  Disabling UAC may not be a good move for security, but I assure it's the first thing I recommend anyone do in order to preserve their sanity.  The actions that prompt UAC in Linux are, for the most part, pretty logical and

    I am hoping 7 is better than Vista and am glad to see this info.  So far, I'm refusing to allow anyone on my network to use Vista even though there have been requests.  I don't need my system admins spending all their time "fixing" the operating system right out of the box and fielding complaints.  I'm testing Win7 as a virtual machine and will see if jumping directly from XP to 7 makes more sense for my users and admins.  

    Instead of new bells and whistles and a ridiculous upsurge in necessary system resources, it would be nice if MS would do what it has needed to do for years and re-write the kernel.  

  • Mac gives me smaller or bigger icons when I want to, but not Win7. Why can't the backups be removed? Shouldn't updates be working and fully compatible? You means those posted ain't safe that I shouldn't even update in the first place?

  • There were a lot of comments saying they wanted "Run as Administrator", but I didn't see any with the option I was looking for, "Run as limited account".  I'm sure a lot of us here fit into the category of poweruser that generally logs in as an admin account and is pretty smart about not running malicious applications/navigating to infected sites.  What I would like though, when I have an application I'm less sure of, or when browsing the internet, is to specify from the outset that I less than trust this application.

    As it is now I have to run a VPC to handle these kinds of issues, but it's cumbersome and in some cases not possible (when not on my machine).

  • as i mailed you earlier (approx half months) it has been found that during connecting windows 7 enabled laptops and pc's from security key enabled WiFi connection it has been observerd that the key which network administrator enters is not secure in this operating system when you go in network properties in security there is provision for show charecter by clicking it,it displays key which admin enters it will create huge loss to Wifi service providers and it has been told to microsoft by me earlier near half a months ago bu this severe security lapse is not concidered by microsoft so,it should be resolved quickly it creates huge challange for individual one country security.

  • Only one thing to say, keep the system protected by default but give possibility to desactivate this security. User mustn't be jailed with something he don't want.

  • Yes it is an annoyance with the popups, sometimes they appear a few times for one action, but I would rather this happen than to have a system that is inferior in security.

  • UAC has had a significant impact on the software ecosystem, Vista users, and Windows itself. I’ve learned a lot about UAC’s impact.

  • User Account Control in Vista stopped Access 2003 Linked Table Manager from providing a connection between the Access Database and Paradox database files. However turning off UAC allowed the connection.

    I have upgraded to Windows 7 and cannot, apparently, now turn off UAC, so my Access MDB cannot now work at all.

    There was never any problem with the same MDB when running under Windows XP.

    Is there a workaround available? (Urgent)

  • Any sports figure who succeeds at a early age seems to give up just being a kid. Maybe now she can just enjoy being herself. <a href=>net-a-porter</a>Good Luck!

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