Deny application network access in windows shell - windows

I'm going to write a script to disable/enable network access for applications in windows. My idea was to write a script that runs a windows shell command that do this.
The scripting is the easy path, but i don't know how to do the "denying" part. Any ideas?


This sounds like a task better suited to letting Windows user / group security handle.
For example, assuming you're on Active Directory and have administration privileges, you could create a user account with the very specific access your app needs, and configure your app to authenticate with the network using that user's credentials.
Then your app through AD would access the network within the constraints of that user account's privileges, and if necessary deny them access to specific network resources.

Related

Mounting CIFS share using C++

Is there a Windows C++ API to execute a command as a different user ? I am trying to mount a CIFS share from a service which is running as sys admin and I am currently logged in as a Kiosk user so when I try to mount the share using "net use .." I get access denied.

With CreateProcessWithLogin, you can execute a command with an arbitrary user provided you have valid credentials. Alternatively, can can use a combination of LogonUser and CreateProcessAsUser / CreateProcessWithToken.
Rather than requiring credentials including a password stored as plaintext (not recommended from a security POV), you could also grant required permissions to the kiosk user so that the current user context is sufficient for accessing the data and/or mapping the network drive.
If that is not an option, your application could have a manually configured persistent network drive as a prerequisite. The credentials would then be managed by Windows.

Opening a handle to a drive in Windows permissions

I'm opening a drive directly via CreateFile to get a handle so I can send scsi commands via IOCtl to custom hardware (which presents as a mass storage device) from a windows service.
The problem is that in order to do this my service needs to run as an administrator (or I get access denied errors). In practice this won't be problem under most circumstances (usually we run as Local System) but under some circumstances we run as a domain account so is there a permission I can give to a domain user account to allow access that is a little finer grained than local administrator to get this working?
Device Driver access permissions for domain users in Windows 7 and SPTI/SCSI operations from a Windows 7 application are variants of the same question but don't give that finer grained answer.

Network access to windows service

I have problem with creating service that has access to files on network disk.
Service must have admin rights and it will be run by users that don't have admin privileges.
I send path as UNC
and file is seen by service but it return ACCES_DENIED errors when try to open or do anything on Network drive.
When I run my service as server , everything works fine.
I try to find answer but everywhere I can found only partial answers that do not help me at all.
========
I read that standard service logged as SYSTEM can't have access to network.
So i tried to log id as
NetworkService, LocalService
It didn't work. After run it as one of those user my service can't save files on c:
Some kind of admin account.But I didn't manage to success on that.
Actually logged user.
I don't know how to get password for current user.
Still this will not work for user without admin rights.
========
Please tell me what can I do?
There are plenty of Services that use somehow network resources. How do they do that?

You need to configure your service to run as a user which has sufficient rights. In this case you are looking for rights to network shares. Typically that's going to need a domain user with appropriate rights. Normally you'd ask your network manager to create a dedicated user account for the purpose.
You appear to be labouring under some false information as to how services work. You talk about running the service under the account of the logged on user. Remember that services run when there are no users logged on. And remember that there may be multiple logged users at any point in time.

For me, the port was getting blocked through firewall, I had to add a inbound rule and specify the port which i was using in my application. This way firewall did not blocked my port for outgoing connections.
References:
https://www.firehousesoftware.com/webhelp/FH/Content/FHEnterprise/FHEnterpriseInstallationGuide/24_StaticPort.htm

Connect share with credentials during setup with different profile

I am working on the examination system and need to implement the following scenario:
User ( standard windows user ) completes the exam and then it is saved on the network share.
For security reasons the share does not have permissions for this user account. So I use impersonation API ( LogonUserEx, ImpersonateLoggedOnUser, RevertToSelf).
It all worked fine when the user with which I do the impersonation had admin privileges on the
local computer but the requirements are that it will be standard user.
With standard user the share is not visible. When I log in interactively with this user the share is visible and writable. So I assume that the standard user can not mount share when not logged in interactively. Is this correct? Is there a workaround?
The only time my code runs with elevated privileges is during the setup of the software.
I thought about using WNetAddConnection2 API but I need the share to be mounted to
this "hidden" user profile and not the administrator one that runs the setup.

Sending a password to a Windows Service

What is the best way to send a password to a Windows Service? Our application needs a password in order to start. I don't care that services are "normally" supposed to run without user interaction. Its good enough for us that an operator can start the application and then log off.
On a unix system, I would just echo the password over stdin but the service has no stdin.
Currently, we use the DPAPI to just store the password using CryptProtectData. While this, works, it presents other problems that are beginning to become troublesome.
I'm guessing that I'll need to use some form of IPC between the service and the application that is sending the password but I'm not sure which method is appropriate, if any.
Thanks

Two main options:
You could listen on a socket on startup and wait for the required password to be supplied (maybe embed an SSH server in there, so that the password cannot be snooped over the wire)
My preferred option would be to read the password from a configuration file (that can be secured to the minimum readership) or registry setting (again, sufficiently secure such that only your service and administrators can read/change it)

Thanks for responding Rowland.
You could listen on a socket on
startup and wait for the required
password to be supplied (maybe embed
an SSH server in there, so that the
password cannot be snooped over the
wire)
I considered that but without certificate verification, wouldn't that leave us open to a man in the middle attack?
My preferred option would be to read
the password from a configuration file
(that can be secured to the minimum
readership) or registry setting
(again, sufficiently secure such that
only your service and administrators
can read/change it)
We're trying to follow "defense in depth" as much as possible such that if an attacker compromised the machine, he would not able to access our application.

You can use kerberos mutual authentication. There are few options and examples there.
But just wondering. On a compromised machine, There may be a key logger. So typing the password is never secure if you want to maintain security in this environment. The same problem exist afaik for unix terminals.

DPAPI in UserMode is really the best option, and storing the encrypted data in a protected location, e.g. registry key with limited ACL.
What exactly were the problems that are beginning to be troublesome? Maybe we can just solve those...

What exactly were the problems that
are beginning to be troublesome? Maybe
we can just solve those...
Currently, the application runs as the Local System account.
Our application stores a number of credentials in an encrypted file and uses the DPAPI (in UserMode) for the encryption.
Thus, when the application is installed, the installer is run as the Local System account. We also have a set of tools that ship with the application, some of which need access to this encrypted file and thus, they too need to run as the Local System account.
By the time the application is installed and started, we're heavily dependent on that account.
We're running into problems because one of our users wants to use the application to access a shared network drive. The Local System account has no such privileges and we can't simply run our service as a different user because our encrypted information is protected under the Local System Account.
We've tried to avoid the process of setting up a user account just for our application because it is installed across many different customers and environments, all of whom have wildly different security policies.

You can access a remote drive from a service running under system account. However, you will need to have credentials & share information to connect to the remote machine. You can use the API wnetaddconnection to gain access. Probably your encrypted file can store this credential as well.

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