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 blogs.msdn.com 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

Leave a Comment
  • Please add 8 and 6 and type the answer here:
  • Post
  • when there is new process (like application or something) run in the system, there is created new unique directory in Program Files. Process will have access into it - there will be "virtual" Program Files, Windows, Documents and Settings created there. Process will have created own Registry file, system will have some central Registry too and processes will see it as part of own (part in read only and part in read write mode - for example info about drivers and extensions assignment). Uninstalling application will be connected with removing "virtual" directory from Program Files, removing process registry file and things put into central Registry by process.

    All processes will be working this way - Explorer, IE, etc. Some default apps will be able for more from box (like RegEdit) - info about this will be saved in Windows directory. It will be possible to give more privileges to each process too.

    UAC will be visible only when application will try to add driver or when network connection will be set. It will be possible to select "always allow for it" and after giving password avoid question again.

  • It seems to me that Windows core must be looked at first, before looking at the security issues, and UAC in particular.

    How does malware infect computers? Which Windows components are typically compromised by malware the most? By now, information collected by UAC must have allowed to collect information about the actions that users usually reject. That would be a good place to start the analysis.

    What can be done to reduce the number of UAC dialogs by changing such concepts as how the Registry is used, for example? Which legacy components can be dropped or replaced with virtual machine hosting processes? The idea is to encourage users to run legacy applications within Virtual Machines that simulate system boot-up from standby (instant VM).

    What can be done to find which Windows components are broken? It is very hard to find holes in the Registry - too much data that is often meaningless even to advanced users. What can be moved out of the registry? SysInternals tools are very useful, but sometimes it still takes hours to find the source of an infection.

    System Restore must be reviewed. Restoring system back to a restore point does not recover enough data. Very often, OS remains infected with malware. Therefore, System Restore is often useless.

    One more thing that can be implemented is to run OS session in the "transaction" mode. Then, when a Windows shutdown or a user log-off is initiated, file system changes can be committed. And, if the OS becomes infected, the changes can be discarded. However, advanced users should be able to review the changes before committing the save. This would eliminate the need for many UAC messages.

  • I agree that "Run As" option I think is a must. UAC messages can be displayed in the active window as a modal dialog if the actions are initiated by a process that has an active window. It would eliminate some user frustration. Sometimes, it is hard to determine which program caused a UAC pop-up, and whether the action was expected.

    User should be able to put applications into the list of trusted applications and permit or disable most common operations that are can be blocked by UAC. User should be able to remember settings for such operations when a UAC dialogs are displayed (add a checkbox or another button). And, developers should be able to incorporate UAC presets into the installation packages so the user would be able to accept recommended settings at once.

    I somewhat agree with users that recommend suspending UAC messages for an application or even all applications for the duration of the session. Security can be compromised, unless running session in "transaction" mode when the changes to the file system are not committed.

  • > I'm waiting a post about WGA. I hope you

    > are able to provide a good protection against

    > privacy for Windows.

    well, it would be good to know, why does alternative method of checking genuine software (downloading application + copying code) connect to Microsoft server and exchange some data. Is it privacy ?

    > I don't why a big company

    > like you unable to win against

    > a small team of hackers

    what man created, man can hack

  • > It seems to me that Windows core

    > must be looked at first, before looking

    > at the security issues, and UAC in particular.

    YES, YES & YES. There must be changed some things on low level and we can speak about things on high level. Microsoft is already loosing some market (because of vista). He can't built new system on exactly the same solutions. Speaking about bells and whistles and "wow" will be not enough, there is required engineering knowledge and hard work.

    Separating components must be done. Not total, because we will loose some functionality. But much bigger than in Vista. When architecture will be correct, we will not need to use so often System Restore, UAC and other.

  • > It seems to me that Windows core

    > must be looked at first, before looking

    > at the security issues, and UAC in particular.

    YES, YES & YES. There must be changed some things on low level and we can speak about things on high level. Microsoft is already loosing some market (because of vista). He can't built new system on exactly the same solutions. Speaking about bells and whistles and "wow" will be not enough, there is required engineering knowledge and hard work.

    Separating components must be done. Not total, because we will loose some functionality. But much bigger than in Vista. When architecture will be correct, we will not need to use so often System Restore, UAC and other.

    Microsoft must hear customers, not only listen.

  • In my opinion, the whole idea of the prompts is flawed at its core, and the model of users is not a reflection of how a real system should be.

    An administrator should have the ability to perform administrative tasks, and it should be assumed that they know what they are doing = they don't need the popups asking them if they are sure.

    A normal user should not have the ability to perform administrative tasks EVER, NEVER EVER!! Don't ask them if they want to - if they are not an administrator, they aren't allowed to do administrative things.

    If a regular user account sincerely needs to perform an administrator action, then you should have to authenticate as an admin/superuser ... can you tell what I'm getting at - sudo - Unix/Linux/MacOSX - that's how they work.

  • In my oppinion for an IT Admin or a power-user the UAC is a real annoyance and productivity killer. As many have already said before me I know exactly why I want to do changes to the Registry or delete files or folders in Program Files or Windows.

    If UAC is a must for Windows 7 I would like to have the following choces (probably anyone who installs and configures Windows for a living will appreciate it):

    - have the choice during initial Windows setup process to Enable or permanently disable UAC

    - if I choose to Enable UAC please let me select if I want it enabled right away or after x minutes after the first log on

    - if I create a new user and I grant it Admin rights I want those rights to be indeed full Admin rights not a slimmed down version

    - allow for the UAC to be tweaked so it will show additional prompts only to the events I choose to monitor

    - make UAC manageble through GPOs at the domain level

    - as other users mentioned before create a distiction between actions made by an actual user and actions made by software

    Probably I can think a dozen more features I would like to see in the UAC but I know that if I would get half of what I listed already I could consider myself lucky.

    Finally, UAC was my main reason why I stayed away from Vista... even with UAC disabled there were times were I felt that my user with full admin priviledges was not actually in full control over the system... we the IT people like to feel in control!

    Thanks!

  • ...and please return the "RunAs" as a choice...

  • @Daniel Smith

    <<Slightly OT but I'd like to remove the dialog box that pops up when you move something to the recycle bin asking if I'm sure I want to do this.  I understand why you do this but I'd like the option to turn this off.>>

    The delete confirmation can easily be disabled. Right click the Recycle Bin desktop icon, select properties. Remove the check mark from the 'Display delete confirmation dialog.

  • I approve totaly the UAC.

    I don't understand why poeple are so upset about it.

    True that most of basic users don't read the prompt and don't know why it's important.

    One day I made a an experiment: I created a message box telling "Your hard disk will be completely erased. Do you want to continue?" and some poeple clicked "yes".

    One shortfall of UAC is that it doesn't intercept certain attempts to modify the system.

    I have seen two softwares which tried to modify the system settings or registry and simply produced nothing or an error from these program without UAC poping up.

    What happens is that some programs don't work because the system is protected but UAC fails to inform you or to let you accept the changes.

  • I think that the implementation of the secure desktop for UAC prompts was a mistake.  It makes the UAC prompts seem much more annoying for several reasons.

    First, it makes the prompts less responsive.  Especially on older hardware, but even on newer hardware it can take over a second for the prompt to appear.  On my computer the UAC prompts are much quicker with the secure desktop disabled.

    Second, it prevents you from multitasking.  When an application generates a UAC prompt you can not work on anything else, you must respond to the prompt to continue using your computer.  If I receive a UAC prompt I'm not expecting I might want to use google to see if there is information about the prompt.  With the secure desktop enabled I would have to cancel the prompt and remember what it said in order to do this.  In general being forced to acknowledge a single dialog box and not being able to use any other program is annoying.

    I'm glad that it is possible to disable the secure desktop for UAC prompts, but I would recommend either making that the default, or making the option more obvious.

  • I have to say I love the amount of people voicing like for UAC, even if they have slightly tweaked it (such as one person disabling the Secure Desktop in favor of just using a password; not perfect, but still using UAC like people SHOULD).

    For those that don't understand it, and furthermore, refuse to (and then turn it off forever)... I won't preach how useful LUA is AGAIN but I will say you are in for a rude awakening. A VERY rude awakening. Expect bad things.

    I like how this article mentioned Standard User accounts being made usable by UAC (A MAJOR PRODUCTIVITY BOOST!!!), but it didn't explain the pain that made that necessary. Even if it did, it might not have done justice. Anyone who has tried to Administrate an XP box with a Standard Account will understand this perfectly; RunAs is a joke for the majority of elevations.

    Speaking of RunAs... I agree with the majority of people who mention it in here. Bring it back; it can elevate to full Administrator (like the Administrator account has) for single tasks, making multiple prompting programs run much smoother. It may need to use a Secure Desktop much like UAC does, but the lack of it is painful.

    Someone made a comment on UAC data being used to blacklist methods used by malware. I have to say that a blacklist is a bad idea in security; whitelisting good programs is much better, and has no false positives to worry about. You wouldn't use a firewall that only blocked where attacks have come from in the past, right? So why is security software like this? With UAC (a whitelist of sorts) I don't need antivirus (a blacklist type security mechanism).

    And as for those who want protected mode of IE without UAC, there is a way to do it *right now*, but I'm not telling. Run UAC; you will be better off.

  • @spacejumper

    "...and please return the "RunAs" as a choice..."

    why? you can do everything you can do with RunAs in the search field of the startmenue...

  • Once again Administrators should have administrators/system rights. The OS should not questions what an Administrator is doing. If the Admin intention is to infect a computer with 100s of viruses thats fine. (It is actually the AV responsibility to prompt the admin in this case). The OS should make it more comfortable for the admin to change stuff. You should expect that the admin is well aware of that installing downloading softwares can be dangerous you do not have to prompt him. However when you prompt an administrator then you should provide detailed information about whats going on.

    When the admin creates a user account he should be able to explicitly set the right for each user. During the UA creation process. That should include for example allowing/prohibiting installing softwares/viruses. However those softwares should only allowed to access stuff in the User security sandbox, and not in the Admin security sandbox.

    If the User wants to do something that requires admin rights then he should be prompted for Admin credentials.

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