All posts by steve

Office 365 Hybrid Configuration Wizard Won’t Launch

Recently I ran into a problem helping a client with their Office 365 Hybrid Configuration. We couldn’t get the Office 365 Hybrid Configuration Wizard (HCW) to launch. We tried running it in Internet Explorer and Google Chrome without success.

It seems the Office 365 team changed the HCW from a standalone Windows executable to a Click-To-Run (C2R) executable. The biggest benefit of using C2R is that whenever it is clicked, the latest version of the program is downloaded and launched.

The problem was something broke the Default Programs association for “.application” extensions. If you open the Default Programs control panel and look at the “.application” filetype, this is what you’ll see:

These settings WON’T WORK!

Change the “.application” file type to be opened with Internet Explorer. Go back to the HCW link and click it.

Error While Opening the Windows Defender in Windows Server 2016

I was reviewing a client’s Microsoft Windows Server 2016 after a security auditing tool discovered it was listening on some suspicious TCP ports, when I opened Settings -> Update & Security and selected Windows Defender.

When I did, I was concerned when I saw this:

C:\Program Files\Windows Defender\msascui.exe
Windows cannot access the specified device, path or file.  You may not have the appropriate permissions to access them.

My first reaction was complete panic!  Many times after a server or workstation becomes infected with a nasty malware or virus, any anti-virus software installed is either disabled or crippled to the point where it wouldn’t function.

I immediately fired up a fresh install of Windows Server 2016 in my lab, disconnected from the Internet, joined our test lab’s domain and recreated the error!

“What the heck!”, I thought.  How can a brand-new Windows Server 2016 machine be doing this?  I did some brief research with Google finding post after post screaming about infected servers and corrupted NTFS permissions, which I could confidently rule out.

So I started doing some testing and eliminating causes by trial and error. Once I had confirmed it wasn’t a file permission issue it occurred to me – User Account Control (UAC)!

I modified the Local Security Policy to enable the following setting and rebooted my test server:

User Account Control: Admin Approval Mode for the Built-in Administrator account

Lo and behold, I could now open Windows Defender!

I’m not sure why it still takes me so long to investigate UAC.  I’ve run into enough issues with it in the past I should know better.  I hope this article helps anyone who is struggling with this issue.


How to Configure Passwordless SSH login in Linux

This process involves two steps:

  • Generating a public authentication key
  • appending it to the remote hosts’ authorized_keys file.

Generate Authentication Key

If an SSH authentication key does not already exist on the client, generate one by running the ssh-keygen command.  When prompted for a passphrase, use a blank passphrase if fully password-less login is desired:

# ssh-keygen
Generating public/private rsa key pair.
Enter file in which to save the key (/home/user/.ssh/id_rsa): 
Created directory '/home/user/.ssh'.
Enter passphrase (empty for no passphrase): 
Enter same passphrase again: 
Your identification has been saved in /home/user/.ssh/id_rsa.
Your public key has been saved in /home/user/.ssh/id_rsa.pub.
The key fingerprint is:
SHA256:SV+/61UbEnJMJeTP4gvRY1Jxwv4HR8Hd2yqCBBt6p74 user@client.domain.local
The key's randomart image is:
+---[RSA 2048]----+
|            o*o++|
|      o     +.=.+|
|     . +.  .o* .o|
|    . o.oo .=o=.o|
|     . +S..o *oB.|
|      . . . * =o=|
|     .     o o..o|
|      .     . .o |
|      E.     oo  |
+----[SHA256]-----+

Copy the Public Key to the Remote Host

Use the ssh-copy-id command to install the public half of the new authentication key to the remote host.  The ssh-copy-id command will automatically append the identity information into the ~/.ssh/authorized_keys file for the specified user on the remote host.  It will create the authorized_keys file if necessary.

#ssh-copy-id -i ~/.ssh/id_rsa.pub user@remotehost.domain.local
/usr/bin/ssh-copy-id: INFO: Source of key(s) to be installed: "/home/user/.ssh/id_rsa.pub"
/usr/bin/ssh-copy-id: INFO: attempting to log in with the new key(s), to filter out any that are already installed
/usr/bin/ssh-copy-id: INFO: 1 key(s) remain to be installed -- if you are prompted now it is to install the new keys
user@remotehost.domain.local's password: 
Number of key(s) added:        1
Now try logging into the machine, with:   "ssh 'user@remotehost.domain.local'" and check to make sure that only the key(s) you wanted were added.