A service, which I'm developing, needs to call ChangeServiceConfig2 to change its configuration parameters. The function requires a service handle. So, to get its handle, the service calls OpenSCManager, which succeeded, and later OpenService. In the parameter lpServiceName of OpenService function I specify the name of the service but I got "Access denied". I changed the access rights in the manifest file to "requireAdministrator" but still got the error.
In general, how could a Windows service get its handle?
When creating the service, the lpServiceStartName argument determines the security context that the service will run in.
From the documentation for CreateService:
If this parameter is NULL, CreateService uses the LocalSystem account.
So in order for your service to run with administrator privilege, you need to specify NULL instead of an account name. According to the comments, you are currently running as Local Service; this does not grant administrator privileges.
Related
I was installing the filebeat application and I noticed that I needed to run powershell as administrator in order to install them. When I checked the service using wmic service get name,startname,status it showed Local System. I'm wondering what this account is as this is neither the user account or the administrator account. Will this always be the case when I install services as administrator? What is the difference if I install it as a normal user and as administrator?
In any case, I've set this service to start automatically when windows start. Would this service start only when the user I used to install it logs in or will it start regardless of which user logs in?
OK, let's unpack that one by one, in no particular order:
Only a user with administrator rights can install a service.
Services that are configured to start automatically are started as soon as Windows is up and running; Windows does not wait until somebody logs in. It makes no difference to the service who the logged-on user is, or whether anybody is logged in at all, unless the service application itself has been explicitly programmed to check.
The program that installs the service decides what account the service uses to run. Windows doesn't care what user account was used to install the service, it doesn't even keep track.
If the program that installs the service wants it to use an ordinary user account, it must know the password for that account. There are various special accounts that a service can run in, these accounts do not require a password. One of these special accounts is Local System.
Local System is the highest-privilege service account in Windows; it has all the same rights as an administrator, and can do things an administrator can't. Local System is also the account that the user-mode part of Windows itself runs in, roughly equivalent to the UNIX root account except that it doesn't have a password.
Additional notes, for completeness:
One alternative to Local System is for the service to run as Local Service or as Network Service, which are non-administrative service accounts. The only difference between the two is that if the computer is joined to an Active Directory domain, the Network Service account has network access to other machines in the domain and the Local Service account does not.
It is also possible to configure a service to run in a special service account that is unique to that particular service. This is mostly useful if you want the service to have access to a particular file or folder, but do not want to give it administrator rights.
Nitpickers corner:
It is I believe technically possible to reconfigure Windows to allow non-administrators to install services, but this is not supported and would be a Very Bad Idea. If you did, though, it would still make no difference who installed the service. Windows doesn't record this information.
Background: I'm writing a service and want to give it as few privileges as necessary.
Virtual Accounts (sometimes "Virtual Service Accounts") are sparsely documented feature new to Windows 7/2008R2 that are automatically managed accounts for services that need minimal privileges but access the network with a computer identity in a domain environment.
My service doesn't need network access, so I'm using LocalService, but I don't like the fact that if I grant access to a file/etc I granting access to all services running as that account.
Is there a least privileged account I can use?
You don't need to change the account the service runs under; LocalService is fine.
Instead, configure the service to have a non-zero SID type, i.e., specify either SERVICE_SID_TYPE_UNRESTRICTED or SERVICE_SID_TYPE_RESTRICTED. You can do this using the ChangeServiceConfig2() function and the SERVICE_CONFIG_SERVICE_SID_INFO option.
You can then grant access to files and other protected resources using the service SID, whose name is NT SERVICE\myservice, rather than LocalService. This will grant access to only your service. (Well, and any other services sharing the same process, but most third-party services run in their own process.)
For least privilege, use SERVICE_SID_TYPE_RESTRICTED. This means that the service can only access protected objects that explicitly grant access to either Everyone, the service SID, the logon session SID, or WRITE_RESTRICTED. You should also use the SERVICE_CONFIG_REQUIRED_PRIVILEGES_INFO option to reduce the privileges granted to the service; many services do not need any privileges at all. (In that case, you may find that you need to specify SE_CHANGE_NOTIFY_NAME rather than an empty list, though I might be misremembering.)
I need to call WNetGetConnection to get the UNC path and it works good when application run as standard user but it returns 1201(ERROR_CONNECTION_UNAVAIL) error code when application run as admin. According to the documentation its working as expected.
If the network connection was made using the Microsoft LAN Manager
network, and the calling application is running in a different logon
session than the application that made the connection, a call to the
WNetGetConnection function for the associated local device will fail.
The function fails with ERROR_NOT_CONNECTED or
ERROR_CONNECTION_UNAVAIL. This is because a connection made using
Microsoft LAN Manager is visible only to applications running in the
same logon session as the application that made the connection. (To
prevent the call to WNetGetConnection from failing it is not
sufficient for the application to be running in the user account that
created the connection.)
that means its not possible at all to get the UNC path from the app running as admin ? Is there some other way ?
This is by design. Network shares created by a non-elevated account are not visible under elevation, and vice versa.
See this question on Super User for discussion of the issue. There is apparently a registry setting that enables mapped drives to be shared between elevated and non-elevated accounts but I've never tried it myself.
Network connections cannot normally be shared across different Windows login sessions. This is regardless of admin account / elevation level. Each Windows login or impersonation session needs to create its own network connections.
I am creating an installer that need to stop and then start a service named "MyService".
The installer is always run as admin, But some times the user of admin group does not have a permission to start and/or stop the service.
In this case I will get access denied when I try to start the service.
I want to check prior to start/stop service that if the user have permission to do so.
Found that using
sc sdshow myservice
This shows the security descriptor and I can GET the SID and access level.
From this finding out access, turned out to be difficult. That it can so have that a group that this user is member of is turned to have no access to start/stop service.
Finding the list of group of a user that he belongs to, I did not get any direct method.
Is there any way to find if the user (I have user name and SID) has permission to start/stop service Myservice?
If not any direct method to get list of groups that the user is member of?
Here's what I want to do:
a program that listens in the network for a message, and when that message is received, if the user is not logged in (for example the computer just powered on and windows displays the classic login screen), it automatically logs in a certain user accordingly to the message. the username and password are known and stored safely inside the computer in a configuration for the program i'm talking about.
What I had in mind was a windows service that starts with the computer and also listens to those messages, and if one is received, then it does it's job
but I have no idea of where to start
(basically i'm trying to login a user without having to type the password, which I said is stored and known - need something mostly like the fingerprint software windows 7 comes with, and the ones that you had to install in vista/xp so that fingerprint login would work (fingerprint was only an example) )
There's two methods to pursue depending upon which operating system you're looking to run under.
For Windows XP, Windows 2000, and Windows Server 2003 you need to create a GINA.DLL. This is a replacement DLL which must follow specific rules which handles the authentication process. In your case your replacement DLL would be known by the service which was listening for your start signal, and it would make a call into the DLL with the username and password as appropriate.
MSDN Magazine article on customizing GINA.DLL
MSDN entry on GINA
For Windows Vista/7 and above you'll need to look into the Credential Provider API.
MSDN Magazine article on Credential Provider API in Vista.
MSDN entry on Credential Provider API
You can use windows auto logon feature to do this.
Create a service which waits for the required data on a network socket. Make sure this service is started after the network service (Tcpip). Modify winlogon service properties (manually) so that it depends on your service. By depends, I mean that winlogon service is started after your service.
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Winlogon\AutoAdminLogon to 1
Once you receive the data on your network socket, set the following registry keys:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Winlogon\DefaultUserName
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Winlogon\DefaultPassword
Once the registry settings are in place, then the winlogon service can read those values and proceed with the login process.
For more details on setting the registry values refer: http://support.microsoft.com/kb/315231
I want clarify a little the suggestion of Vikram.exe.
Of cause the usage of AutoAdminLogon seems native for the problem, but saving of the password in registry as a clear text under HKLM\...\Winlogon\DefaultPassword is not good. Since Windows 2000 it is supported the usage of the secrets DefaultPassword which makes the same effect as the DefaultPassword registry value (see Protecting the Automatic Logon Password for the code example).
Another way to force user login or to do any other actions on the login screen is switching to the Winlogon desktop (full name WinSta0\Winlogon). You can use SwitchDesktop and SetProcessWindowStation to do this (see Window Stations and Desktops). If the service run under System account you will have all rights to do this. Depend on the configuration of your service it could be also needed to use SetTokenInformation with TokenSessionId to change the current session id. After the service process will run on the WinSta0\Winlogon desktop you can use functions like FindWindow and other GUI API to place any information in controls of the window (user name, password and so on) of other process. So you can implement more complex scenarios.
Firstly let me just say im not 100% sure how to fully complete such a application but I have a few tips.
you will need to create a Windows Service that starts during the Pre-Login, you can create a service in C#, An example of creating a C# Service is linked below:
http://msdn.microsoft.com/en-us/library/zt39148a(VS.80).aspx
Within your application you would set the property Startup Type to Automatic, This will automatically start your service on boot.
You should know that windows services run under a secure context by account so you will have to get your service to run with privs do do this.
In your Service Properties you can Click Log On and you can
To specify that the service uses the Local Service account, click This account, and then type the following NT AUTHORITY\LocalService.
To specify that the service uses the Network Service account, click This account, and then type the following NT AUTHORITY\NetworkService.
As your trying to do this remotly you will have to look at WMI (Windows Management Instrumentation) and you will be able to start/stop and send commands to your service.
Your service then would send a command to the Login Management (Not Sure of the name).
you may also wish to check this WOL class which will switch the computer on remotely as long as it supports Wake On LAN, If this is for a corporate environment then I advise you to check your network cards to make sure they are supported
http://www.codeproject.com/KB/IP/wolclass.aspx
I know of some education software that I use for schools that's called CC4 ( http://www.rm.com/shops/rmshop/story.aspx?cref=PS1026195 ) and we can do exactly what you need within this system, I'm not fully sure of how it works fully but i believe it takes the same principles described above.