Cloud App Security: block TOR Browser (Anonymous IP)

Hi all, Alan here again with a new article, I'm a Customer Engineer from Italy on Identity and Security. 

I want to show you block TOR browser using Cloud App Security, simple and fast! 

During the last few months, I had several customers requesting  block sign-in from anonymous Ip Addresses. One example would be someone using TOR Browser. I started playing around with CAS and finally found a quick solution. Continue reading to find out more.  

We will use Conditional Access policy” with Session Control together with “Cloud App Security Conditional Access App Control”. 

We will start creating a “special” Condition Access policy that will enable the APP in CAS, let's see how. 

PS: the APP will appear in Cloud App Security Conditional Access App Control directly after the user start /using it.

You will need access to you tenant's Azure AD (portal.azure.com) and Cloud App Security (mycompany. portal.cloudappsecurity.com). 

Thirst thing to do is create an Azure AD Conditional Access policy: 

1. Navigate to your Azure

2. Under Manage click on Security

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3. Click on Conditional Access

4. Select New Policy

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5. Give it a Name

6. Select to which users it will apply

7. Select the cloud application, for this demo I will select Office 365

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8. Go to Session and select Use Conditional Access App Control

9. Select Use Custom Policy  

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10. Click Select 

11. Enable the policy and click Create 

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Once this is done the first time users log in Office 365 suite the application will be integrated in Cloud App Security 

Open Cloud App Security portal : https://mycompany. portal.cloudappsecurity.com 

On the top right side you have the configuration wheel, click and select “IP Address ranges” as shown below 

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One interesting thing is that if you filter for one of the following Tags “Tor, Anonymous Proxy or Botnet” you will see it matches the following rule  

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CAS has the “intelligence” to know which are these suspicious IP Addresses or networks 

Here some other details Create anomaly detection policies in Cloud App Security | Microsoft Docs 

  • Activity from anonymous IP addresses 
  • Activity from suspicious IP addresses, Botnet C&C 
  • Activity from a TOR IP address 

Back to our Connected Apps: 

1. Go to Connected Apps 

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2. In the central pane you will have three tabs, select “Conditional Access App Control apps”.

   You will get a list of applications for which you can start creating CAS policies 

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3. Now browse to Control menu and select “Policies”

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4. Select “ + Create policy” 

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The important part here is FILTERS and ACTIONS

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5. Click on “Create” (you will see it listed)

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Access Office portal from the TOR Browser (use a valid user account from your Azure AD)

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GREAT!!

Hope this article gives some hints on use Cloud App Security which I think is a great tool, simple and powerful and can really help enhance your security posture. 

Regards 

Alan @CE  

Customer Engineer – Microsoft Italy 

Useful Resources: 

Zero Trust Maturity Assessment Tool | Microsoft Security 

 

This article was originally published by Microsoft's PowerShell Community. You can find the original article here.