What precisely does 'Run as administrator' do?

128,349

Solution 1

When you log on Windows creates an access token. This identifies you, the groups you are a member of and your privileges. And note that whether a user is an administrator or not is determined by whether the user is a member of the Administrators group.

Without UAC, when you run a program it gets a copy of the access token, and this controls what the program can access.

With UAC, when you run a program it gets a restricted access token. This is the original access token with "Administrators" removed from the list of groups (and some other changes). Even though your user is a member of the Administrators group, the program can't use Administrator privileges.

When you select "Run as Administrator" and your user is an administrator the program is launched with the original unrestricted access token. If your user is not an administrator you are prompted for an administrator account, and the program is run under that account.

Solution 2

So ... more digging, with the result. It seems that although I ran one process normal and one "As Administrator", I had UAC off. Turning UAC to medium allowed me to see different results. Basically, it all boils down to integrity levels, which are 5.

Browsers, for example, run at Low Level (1), while services (System user) run at System Level (4). Everything is very well explained in Windows Integrity Mechanism Design . When UAC is enabled, processes are created with Medium level (SID S-1-16-8192 AKA 0x2000 is added) while when "Run as Administrator", the process is created with High Level (SID S-1-16-12288 aka 0x3000).

So the correct ACCESS_TOKEN for a normal user (Medium Integrity level) is:

0:000:x86> !token
Thread is not impersonating. Using process token...
TS Session ID: 0x1
User: S-1-5-21-1542574918-171588570-488469355-1000
Groups:
 00 S-1-5-21-1542574918-171588570-488469355-513
    Attributes - Mandatory Default Enabled
 01 S-1-1-0
    Attributes - Mandatory Default Enabled
 02 S-1-5-32-544
    Attributes - DenyOnly
 03 S-1-5-32-545
    Attributes - Mandatory Default Enabled
 04 S-1-5-4
    Attributes - Mandatory Default Enabled
 05 S-1-2-1
    Attributes - Mandatory Default Enabled
 06 S-1-5-11
    Attributes - Mandatory Default Enabled
 07 S-1-5-15
    Attributes - Mandatory Default Enabled
 08 S-1-5-5-0-1908477
    Attributes - Mandatory Default Enabled LogonId
 09 S-1-2-0
    Attributes - Mandatory Default Enabled
 10 S-1-5-64-10
    Attributes - Mandatory Default Enabled
 11 S-1-16-8192
    Attributes - GroupIntegrity GroupIntegrityEnabled
Primary Group:   LocadDumpSid failed to dump Sid at addr 000000000266b458, 0xC0000078; try own SID dump.
s-1-0x515000000
Privs:
 00 0x000000013 SeShutdownPrivilege               Attributes -
 01 0x000000017 SeChangeNotifyPrivilege           Attributes - Enabled Default
 02 0x000000019 SeUndockPrivilege                 Attributes -
 03 0x000000021 SeIncreaseWorkingSetPrivilege     Attributes -
 04 0x000000022 SeTimeZonePrivilege               Attributes -
Auth ID: 0:1d1f65
Impersonation Level: Anonymous
TokenType: Primary
Is restricted token: no.

Now, the differences are as follows:

S-1-5-32-544
Attributes - Mandatory Default Enabled Owner

for "As Admin", while

S-1-5-32-544
Attributes - DenyOnly

for non-admin.

Note that S-1-5-32-544 is BUILTIN\Administrators. Also, there are fewer privileges, and the most important thing to notice:

admin:

S-1-16-12288
Attributes - GroupIntegrity GroupIntegrityEnabled

while for non-admin:

S-1-16-8192
Attributes - GroupIntegrity GroupIntegrityEnabled

I hope this helps.

Further reading: http://www.blackfishsoftware.com/blog/don/creating_processes_sessions_integrity_levels

Solution 3

UPDATE

"Run as Aministrator" is just a command, enabling the program to continue some operations that require the Administrator privileges, without displaying the UAC alerts.

Even if your user is a member of administrators group, some applications like yours need the Administrator privileges to continue running, because the application is considered not safe, if it is doing some special operation, like editing a system file or something else. This is the reason why Windows needs the Administrator privilege to execute the application and it notifies you with a UAC alert. Not all applications need an Amnistrator account to run, and some applications, like yours, need the Administrator privileges.

If you execute the application with 'run as administrator' command, you are notifying the system that your application is safe and doing something that requires the administrator privileges, with your confirm.

If you want to avoid this, just disable the UAC on Control Panel.

If you want to go further, read the question Difference between "Run as Administrator" and Windows 7 Administrators Group on Microsoft forum or this SuperUser question.

Solution 4

Things like "elevates the privileges", "restricted access token", "Administrator privilege" ... what the heck is administrator privilege anyway? are nonsense.

Here is an ACCESS_TOKEN for a process normally run from a user belonging to Administrators group.

0: kd> !process 0 1 test.exe
PROCESS 87065030  SessionId: 1  Cid: 0d60    Peb: 7ffdf000  ParentCid: 0618
    DirBase: 2f22e1e0  ObjectTable: a0c8a088  HandleCount:   6.
    Image: test.exe
    VadRoot 8720ef50 Vads 18 Clone 0 Private 83. Modified 0. Locked 0.
    DeviceMap 8936e560
    Token                             935c98e0
0: kd> !token -n 935c98e0
_TOKEN 935c98e0
TS Session ID: 0x1
User: S-1-5-21-2452432034-249115698-1235866470-1000 (no name mapped)
User Groups: 
 00 S-1-5-21-2452432034-249115698-1235866470-513 (no name mapped)
    Attributes - Mandatory Default Enabled 
 01 S-1-1-0 (Well Known Group: localhost\Everyone)
    Attributes - Mandatory Default Enabled 
 02 S-1-5-32-544 (Alias: BUILTIN\Administrators)
    Attributes - Mandatory Default Enabled Owner 
 03 S-1-5-32-545 (Alias: BUILTIN\Users)
    Attributes - Mandatory Default Enabled 
 04 S-1-5-4 (Well Known Group: NT AUTHORITY\INTERACTIVE)
    Attributes - Mandatory Default Enabled 
 05 S-1-2-1 (Well Known Group: localhost\CONSOLE LOGON)
    Attributes - Mandatory Default Enabled 
 06 S-1-5-11 (Well Known Group: NT AUTHORITY\Authenticated Users)
    Attributes - Mandatory Default Enabled 
 07 S-1-5-15 (Well Known Group: NT AUTHORITY\This Organization)
    Attributes - Mandatory Default Enabled 
 08 S-1-5-5-0-85516 (no name mapped)
    Attributes - Mandatory Default Enabled LogonId 
 09 S-1-2-0 (Well Known Group: localhost\LOCAL)
    Attributes - Mandatory Default Enabled 
 10 S-1-5-64-10 (Well Known Group: NT AUTHORITY\NTLM Authentication)
    Attributes - Mandatory Default Enabled 
 11 S-1-16-12288 (Label: Mandatory Label\High Mandatory Level)
    Attributes - GroupIntegrity GroupIntegrityEnabled 
Primary Group: S-1-5-21-2452432034-249115698-1235866470-513 (no name mapped)
Privs: 
 05 0x000000005 SeIncreaseQuotaPrivilege          Attributes - 
 08 0x000000008 SeSecurityPrivilege               Attributes - 
 09 0x000000009 SeTakeOwnershipPrivilege          Attributes - 
 10 0x00000000a SeLoadDriverPrivilege             Attributes - 
 11 0x00000000b SeSystemProfilePrivilege          Attributes - 
 12 0x00000000c SeSystemtimePrivilege             Attributes - 
 13 0x00000000d SeProfileSingleProcessPrivilege   Attributes - 
 14 0x00000000e SeIncreaseBasePriorityPrivilege   Attributes - 
 15 0x00000000f SeCreatePagefilePrivilege         Attributes - 
 17 0x000000011 SeBackupPrivilege                 Attributes - 
 18 0x000000012 SeRestorePrivilege                Attributes - 
 19 0x000000013 SeShutdownPrivilege               Attributes - 
 20 0x000000014 SeDebugPrivilege                  Attributes - 
 22 0x000000016 SeSystemEnvironmentPrivilege      Attributes - 
 23 0x000000017 SeChangeNotifyPrivilege           Attributes - Enabled Default 
 24 0x000000018 SeRemoteShutdownPrivilege         Attributes - 
 25 0x000000019 SeUndockPrivilege                 Attributes - 
 28 0x00000001c SeManageVolumePrivilege           Attributes - 
 29 0x00000001d SeImpersonatePrivilege            Attributes - Enabled Default 
 30 0x00000001e SeCreateGlobalPrivilege           Attributes - Enabled Default 
 33 0x000000021 SeIncreaseWorkingSetPrivilege     Attributes - 
 34 0x000000022 SeTimeZonePrivilege               Attributes - 
 35 0x000000023 SeCreateSymbolicLinkPrivilege     Attributes - 
Authentication ID:         (0,14e4c)
Impersonation Level:       Anonymous
TokenType:                 Primary
Source: User32             TokenFlags: 0x2000 ( Token in use )
Token ID: d166b            ParentToken ID: 0
Modified ID:               (0, d052f)
RestrictedSidCount: 0      RestrictedSids: 00000000
OriginatingLogonSession: 3e7

... and here is an ACCESS_TOKEN for a process normally run by the same user with "Run as administrator".

TS Session ID: 0x1
User: S-1-5-21-2452432034-249115698-1235866470-1000 (no name mapped)
User Groups: 
 00 S-1-5-21-2452432034-249115698-1235866470-513 (no name mapped)
    Attributes - Mandatory Default Enabled 
 01 S-1-1-0 (Well Known Group: localhost\Everyone)
    Attributes - Mandatory Default Enabled 
 02 S-1-5-32-544 (Alias: BUILTIN\Administrators)
    Attributes - Mandatory Default Enabled Owner 
 03 S-1-5-32-545 (Alias: BUILTIN\Users)
    Attributes - Mandatory Default Enabled 
 04 S-1-5-4 (Well Known Group: NT AUTHORITY\INTERACTIVE)
    Attributes - Mandatory Default Enabled 
 05 S-1-2-1 (Well Known Group: localhost\CONSOLE LOGON)
    Attributes - Mandatory Default Enabled 
 06 S-1-5-11 (Well Known Group: NT AUTHORITY\Authenticated Users)
    Attributes - Mandatory Default Enabled 
 07 S-1-5-15 (Well Known Group: NT AUTHORITY\This Organization)
    Attributes - Mandatory Default Enabled 
 08 S-1-5-5-0-85516 (no name mapped)
    Attributes - Mandatory Default Enabled LogonId 
 09 S-1-2-0 (Well Known Group: localhost\LOCAL)
    Attributes - Mandatory Default Enabled 
 10 S-1-5-64-10 (Well Known Group: NT AUTHORITY\NTLM Authentication)
    Attributes - Mandatory Default Enabled 
 11 S-1-16-12288 (Label: Mandatory Label\High Mandatory Level)
    Attributes - GroupIntegrity GroupIntegrityEnabled 
Primary Group: S-1-5-21-2452432034-249115698-1235866470-513 (no name mapped)
Privs: 
 05 0x000000005 SeIncreaseQuotaPrivilege          Attributes - 
 08 0x000000008 SeSecurityPrivilege               Attributes - 
 09 0x000000009 SeTakeOwnershipPrivilege          Attributes - 
 10 0x00000000a SeLoadDriverPrivilege             Attributes - 
 11 0x00000000b SeSystemProfilePrivilege          Attributes - 
 12 0x00000000c SeSystemtimePrivilege             Attributes - 
 13 0x00000000d SeProfileSingleProcessPrivilege   Attributes - 
 14 0x00000000e SeIncreaseBasePriorityPrivilege   Attributes - 
 15 0x00000000f SeCreatePagefilePrivilege         Attributes - 
 17 0x000000011 SeBackupPrivilege                 Attributes - 
 18 0x000000012 SeRestorePrivilege                Attributes - 
 19 0x000000013 SeShutdownPrivilege               Attributes - 
 20 0x000000014 SeDebugPrivilege                  Attributes - 
 22 0x000000016 SeSystemEnvironmentPrivilege      Attributes - 
 23 0x000000017 SeChangeNotifyPrivilege           Attributes - Enabled Default 
 24 0x000000018 SeRemoteShutdownPrivilege         Attributes - 
 25 0x000000019 SeUndockPrivilege                 Attributes - 
 28 0x00000001c SeManageVolumePrivilege           Attributes - 
 29 0x00000001d SeImpersonatePrivilege            Attributes - Enabled Default 
 30 0x00000001e SeCreateGlobalPrivilege           Attributes - Enabled Default 
 33 0x000000021 SeIncreaseWorkingSetPrivilege     Attributes - 
 34 0x000000022 SeTimeZonePrivilege               Attributes - 
 35 0x000000023 SeCreateSymbolicLinkPrivilege     Attributes - 
Authentication ID:         (0,14e4c)
Impersonation Level:       Anonymous
TokenType:                 Primary
Source: User32             TokenFlags: 0x2000 ( Token in use )
Token ID: ce282            ParentToken ID: 0
Modified ID:               (0, cddbd)
RestrictedSidCount: 0      RestrictedSids: 00000000
OriginatingLogonSession: 3e7

As you see, the only difference is the token ID:

Token ID: d166b            ParentToken ID: 0
Modified ID:               (0, d052f)

vs

Token ID: ce282            ParentToken ID: 0
Modified ID:               (0, cddbd)

Sorry, I can't add much light into this yet, but I am still digging.

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128,349
Jonathan Hartley
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Jonathan Hartley

Made out of meat.

Updated on February 22, 2020

Comments

  • Jonathan Hartley
    Jonathan Hartley about 4 years

    On Windows 7, I have a command-line program that fails due to file write permission errors, and popping up annoying UAC dialogs every time I run command-line programs that are from an 'unknown publisher'.

    However, if I start my console by right clicking and choosing 'run as administrator', then the install works fine, even if the UAC dialogs are still present.

    My user is already a member of the 'administrators' group, so what precisely does 'run as administrator' do that makes my install work?

    My specific question is precisely: What does 'run as administrator' do? Neither of the answers thus far address this. (for example, does it run the new process as the 'Administrator' user? Or does it run the process as the current user, but with elevated privileges? If so, what privileges? How does that differ from the privileges I get from my user being in the 'Administrators' group?

    (Specifically, I'm using the 'Console' from SourceForge, not a regular CMD window, but I don't think that's important. This is all while installing the Python 'distribute' package by running 'python distribute_setup.py' on a newly installed Python3 MSI from python.org. It's a 32-bit Python on 64-bit Windows. See Installing Python and distribute on Windows 7 gives "Writing failed ... permission denied")