ARR: Block PowerShell access to Exchange

In this tutorial, I will show you how to block PowerShell remote access to Exchange with ARR. As a security measure, if you use IIS ARR to publish Exchange servers to the Internet, you must block PowerShell remote access. By default, it is possible to remotely administer an Exchange server with PowerShell, we find all …

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Proxmox: use the integrated Firewall to secure virtual machines

In this tutorial, we will see how to use the Firewall functionality integrated into Proxmox to secure virtual machines and manage network flows. Presentation of the firewall in Proxmox Proxmox allows you to manage a Firewall at the Hypervisor level which allows you to manage network flows at the levels: This configuration can be done …

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Exchange 2016: Enable Extended Protection

In this tutorial, I will explain to you how to activate extended protection (Exchange Extended Protection) on Exchange 2016 (and 2019 if you do not have CU14 which automatically activates it) which will allow you to protect yourself from CVE-2024 -21410. Exchange Extended Protection is in fact an enhanced security configuration for Exchange 2016 / …

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Nginx – GeoIP: configuration

In this new tutorial dedicated to Nginx, I will explain to you how to configure GeoIP in order to be able to set filters (restrictions) based on the country of your visitors. GeoIP will allow us to determine the country (see city) of a visitor based on their IP address, for this we will rely …

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PowerShell: sign scripts

In this tutorial, I will explain how to sign your scripts. Before going into the subject, we will see why signing the scripts, the main reason is security. If your environment (computers + servers) is configured to run only signed scripts and a PowerShell script is launched in a malicious file, it will be neutralized …

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Ubuntu: enable the firewall and manage it with UFW

In this tutorial, I will explain how to activate the firewall on a computer with Ubuntu and manage it with UFW. UFW for Uncomplicated Firewall is a simplified Netfilter command line utility, it is a simple alternative to iptables, which allows to manage firewall rules. If UFW is not installed, use the following command to …

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Windows Server: disable a cipher suite

In this tutorial, I will walk you through how to disable a cipher suite also call cipher. If you arrive on this tutorial by a search engine, there is a good chance that it is due to a vulnerability test and that you have an alert that goes up because vulnerable cryptographic suites (cipher) are …

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Crowdsec: protecting Windows servers

In a previous tutorial, I explained how to protect your Linux servers with Crowdsec in order to block “malicious” traffic. For almost 2 months now, the Crowdsec version has been available for Windows. If you are not yet familiar with Crowdsec, here is a brief presentation: Crowdsec will analyze different log files (Web, firewall, SSH, …

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Active Directory: change the KrbTgt account password

In this tutorial, I will explain how to change the password of the KrbTgt account. Before explaining how to change the password of this account, I will give you some explanations. Who is krbtgt? The krbtgt account is a disabled service account in the Active Directory, which is used for the distribution of Kerberos Tickets, …

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Active Directory: Secure Domain Join to Domain Admins

In this tutorial, we will address a security point on an Active Directory environment, which is the domain joining of computers. What you need to know (some administrators don’t know this), all domain users can join a computer to a domain, they can even join up to 10 computers. Domain administrators have no limit as …

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