Powershell tidbit of the week

Some of you are familiar with SSLLabs.com

Of those who have used it, some of you probably have run into at least one of these limitations:
It doesn't work for sites on your intranet. It doesn't work for sites with no DNS. It doesn't work with SNI sites (sites whit more than one site on a server under different DNS names). It doesn't work  for any port other than 443, and it has to be a web server, not a mail server. so no way to test TLS is working  on your SMTP server and what ciphers it uses.... but NMAP has that if you can remember what command line options to feed it.

I put these 3 lines in a file called testTLSCiphers.ps1 to make it easier for me to remember, and you might want to do that too.

$ServerName = Read-Host -Prompt 'Input your server  name'

$Port = Read-Host -Prompt 'Input your server TCP port number (443 is most common)'
nmap --script ssl-enum-ciphers -p $Port $ServerName



The output looks something like this:

PS C:\Users\rod> C:\scripts\Powershell scripts\testTLSCiphers.ps1
Input your server  name: internalsite.local
Input your server TCP port number (443 is most common): 443
Starting Nmap 6.49BETA1 ( http://nmap.org ) at 2016-06-01 15:29 Eastern Daylight Time
Nmap scan report for internalsite.local (192.168.1.6)
Host is up (0.0010s latency).
PORT    STATE SERVICE
443/tcp open  https
| ssl-enum-ciphers:
|   TLSv1.0:
|     ciphers:
|       TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA (dh 256) - A
|       TLS_DHE_RSA_WITH_AES_256_CBC_SHA (dh 256) - A
|       TLS_DHE_RSA_WITH_CAMELLIA_256_CBC_SHA (dh 256) - A
|       TLS_RSA_WITH_AES_256_CBC_SHA (rsa 2048) - A
|       TLS_RSA_WITH_CAMELLIA_256_CBC_SHA (rsa 2048) - A
|       TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA (dh 256) - A
|       TLS_DHE_RSA_WITH_AES_128_CBC_SHA (dh 256) - A
|       TLS_DHE_RSA_WITH_CAMELLIA_128_CBC_SHA (dh 256) - A
|       TLS_RSA_WITH_AES_128_CBC_SHA (rsa 2048) - A
|       TLS_RSA_WITH_CAMELLIA_128_CBC_SHA (rsa 2048) - A
|     compressors:
|       NULL
|     cipher preference: server
|   TLSv1.1:
|     ciphers:
|       TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA (dh 256) - A
|       TLS_DHE_RSA_WITH_AES_256_CBC_SHA (dh 256) - A
|       TLS_DHE_RSA_WITH_CAMELLIA_256_CBC_SHA (dh 256) - A
|       TLS_RSA_WITH_AES_256_CBC_SHA (rsa 2048) - A
|       TLS_RSA_WITH_CAMELLIA_256_CBC_SHA (rsa 2048) - A
|       TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA (dh 256) - A
|       TLS_DHE_RSA_WITH_AES_128_CBC_SHA (dh 256) - A
|       TLS_DHE_RSA_WITH_CAMELLIA_128_CBC_SHA (dh 256) - A
|       TLS_RSA_WITH_AES_128_CBC_SHA (rsa 2048) - A
|       TLS_RSA_WITH_CAMELLIA_128_CBC_SHA (rsa 2048) - A
|     compressors:
|       NULL
|     cipher preference: server
|   TLSv1.2:
|     ciphers:
|       TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (dh 256) - A
|       TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256 (dh 256) - A
|       TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA384 (dh 256) - A
|       TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA (dh 256) - A
|       TLS_DHE_RSA_WITH_AES_256_GCM_SHA384 (dh 256) - A
|       TLS_DHE_RSA_WITH_AES_256_CBC_SHA256 (dh 256) - A
|       TLS_DHE_RSA_WITH_AES_256_CBC_SHA (dh 256) - A
|       TLS_DHE_RSA_WITH_CAMELLIA_256_CBC_SHA (dh 256) - A
|       TLS_RSA_WITH_AES_256_GCM_SHA384 (rsa 2048) - A
|       TLS_RSA_WITH_AES_256_CBC_SHA256 (rsa 2048) - A
|       TLS_RSA_WITH_AES_256_CBC_SHA (rsa 2048) - A
|       TLS_RSA_WITH_CAMELLIA_256_CBC_SHA (rsa 2048) - A
|       TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256 (dh 256) - A
|       TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA (dh 256) - A
|       TLS_DHE_RSA_WITH_AES_128_GCM_SHA256 (dh 256) - A
|       TLS_DHE_RSA_WITH_AES_128_CBC_SHA256 (dh 256) - A
|       TLS_DHE_RSA_WITH_AES_128_CBC_SHA (dh 256) - A
|       TLS_DHE_RSA_WITH_CAMELLIA_128_CBC_SHA (dh 256) - A
|       TLS_RSA_WITH_AES_128_GCM_SHA256 (rsa 2048) - A
|       TLS_RSA_WITH_AES_128_CBC_SHA256 (rsa 2048) - A
|       TLS_RSA_WITH_AES_128_CBC_SHA (rsa 2048) - A
|       TLS_RSA_WITH_CAMELLIA_128_CBC_SHA (rsa 2048) - A
|     compressors:
|       NULL
|     cipher preference: server
|_  least strength: A
Nmap done: 1 IP address (1 host up) scanned in 3.38 seconds

Is It a VM?

Having a hard time keeping track of which machines on your network are virtual?

I have just the script for you. I wanted to have a way to quickly find out what machines were virtual at work, so I whipped this up in PowerShell today.

Param(
    [string]$ComputerName = 'localhost',
    [string]$ComputersListFile
)

if ($ComputersListFile) {$computers = Get-Content -Path $ComputersListFile} else {$computers = $ComputerName}
if ($ComputerName -eq'localhost')
    {
        if((Get-WmiObject -Class win32_bios).SerialNumber.StartsWith("VMware")) {Write-Output "This machine is a VM!"} else {Write-Output "This machine is probably not a VM"}
    }
else
    {
        invoke-command -ComputerName $computers -ScriptBlock {$hostname = hostname; if((Get-WmiObject -Class win32_bios).SerialNumber.StartsWith("VMware")) {Write-Output "$hostname is a VM!"} else {Write-Output "$hostname probably is not a VM"}}
    }

This only works as it is for VMWare virtualization, not for Hyper-V or VirtualBox, but it would be easy to add tests for those too. The test is to look at the BIOS SerialNumber and see if it starts with the string "VMware". It's just that simple. ...You could also look at the MAC address of the NIC and see if the first few digits match one of the VMWare prefixes, but the BIOS string was easier.


Run it like this:

.\IsItAVM.ps1 -ComputerName computer1, computer2, computer3

or like this if you have a list of computers already in a file:

.\IsItAVM.ps1 -ComputersListFile U:\computers.txt

Of course, this will only work if the computer you are testing is Windows with PowerShell and has PowerShell remoting enabled, and you are not blocked by a firewall... but in an IT environment where PowerShell is being used for management this fits nicely.

Have fun!

--
Edit: Added a little bit of code to better handle the localhost case. If you just run it as .\IsItAVM.ps1 or manually specify just localhost in the -ComputerName then it will not try to use Invoke-Command, so it will not need remoting turned on for a localhost check. Also it gives a slightly different message on a localhost check.

Test Your Passwords

This is a little follow-up to the post about learning to program in python.
I thought I would throw some code out there for people to play with.

This program is written in python3. It prompts the user to enter a password that they want to test and compares it to complexity requirements and then checks if it is in a file called passwords.txt in the working directory.  It will tell the user if the password meets complexity requirements (currently set for windows' standard for complexity (8+ characters and 3 of the 4 categories: upper case, lower case, number or special characters)  There are some unused functions in this such as num_specials() that are there in case you want to customize it for stricter password requirements.

You will need to provide a passwords.txt file with one word per line of passwords that the user should not use. A good place to look for password lists is pastebin.com

If you are learning python then take a look at the code, run it in IDLE, play with the functions, see if you can extend it to do something cool.

If you are not learning python that's cool just place a password.txt file in the same directory full of words you don't think are good to use (The top 10 most used passwords is a start), and run it like so:

python3 passwordStrengthChecker.py

 Anyway, here is that code:

Want To Learn To Program A Computer?

If you have never taken a computer programming course before I'd strongly recommend picking up python as your first programming language. (version 3 if you are starting from scratch)

Take a beginner's course over at Coursera.  I highly recommend the University of Toronto one, Learn to Program: The Fundamentals, which is just wrapping up it's first semester now (and should be starting again soon) Paul and Jen's approach of teaching functions first, starting with defining exactly what the function should do, including examples of inputs and the expected outputs, in the docstring, then moving on to actually coding the function to do that is much easier to get your head around than the way I learned programming back in the early to mid 1990's.

Of course there is also Google's Python Class that is available on-demand, but not as interactive.There is thenewboston's YouTube tutorials, which are really engaging and perfect for new programmers.
Or there's Codecademy: Python or if those methods don't work for you, there's Learn Python the hard way pick what works for you. They are all free.

Pick up a free e-book, or perhaps several of them, from http://pythonbooks.revolunet.com/

I'd recommend starting with Think Python: How to Think Like a Computer Scientist or Dive Into Python 3.

The main thing that holds a lot of us back from learning how to code is not having an idea of what we would like to do with the code. Sometimes all it takes is just sitting back and thinking about problems that you'd like to solve, tasks you do repeatedly every day, every week or every month that could be simplified because you do the same thing every time, again and again. Those are things that computer programs are good for.

I manage a lot of windows computers. Some of them are on the old side, running dangerously close at times to the limits of what their hard disks can hold. Time and again, I found myself going in and deleting uninstall files for updates I knew I would never be uninstalling, just to free up a little space. So, I wrote a program that looks for those files and checks how old they are. If an update was installed more than 90 days ago it deletes the uninstall folder for it. Launching that program saves a bit of precious time each time I find I'm in that position of having to free up some disk space ASAP.

Sit down and think, what tasks like that could you automate? I bet there are at least a few.

Another one was a program that reads a comma separated list of computers (name, ip address, mac address) and uses Wake On LAN to wake the computers in that list up at a specific time. At first I had it call a command line based wake on lan program I downloaded from the net, but later I revised it to create and send the WOL Magic Packets itself ...The possibilities are basically endless.