If you don’t know why you need a firewall it’s because you are not very tech savy. Don’t worry. You can discover by yourself why you need one. The router sitting in your house has one installed in it. And please don’t disable that by any mean. You can check why a firewall is important […]

The firewall

Linux VS open source UNIX
Linux is the mainstream UNIX-like platform of choice in the modern world. There are valid open source code base alternatives from which many businesses have benefited from. This is a different approach on both.

Why FreeBSD
In the following lines you will find a brief but sort of complete explanation about what is FreeBSD and why FreeBSD might be of your interest. If you are already a Mac or Linux user this could be more relevant for you than you would imagine. Enjoy. FreeBSD is an operating system, a unix-like operating […]

Exploiting CVE-2019-0708 Remote Desktop Protocol on Windows
The CVE-2019-0708 is the number assigned to a very dangerous vulnerability found in the RDP protocol in Windows sytems. This is also known as the ‘Blue Keep’ vulnerability. The issue was so critical that Microsoft did even release patches to unsupported operating systems such as Windows XP or Server 2003. To this day there are […]

How to mitigate Spectre and Meltdown on an HP Proliant server with FreeBSD
As recently announced in a previous article I wanted to write a couple of guides on how to mitigate Spectre and Meltdown vulnerabilities in GNU/Linux and UNIX environments. It is always a good and I hope a standard practice to have your systems patched and if they aren’t for whatever the reason (that legacy thing […]

How to detect a WAF – Web Application Firewall
From a penetration testing perspective to identify if a Web Application Firewall (WAF) is in place is essential. The next question is, does an administrator need to know this? My view is, anyone who is in charge of any system that has implemented some sort of WAF needs to verify this tool is working, at […]

Absolute FreeBSD 3rd Edition Book Review
Absolute FreeBSD 3rd Edition from Michael W. Lucas, printed by ‘No Starch Press’, is an absolute (pun intended) must have for every BSD user and I’d go so far as to say to every UNIX and Linux user indeed. If you find the articles in Adminbyaccident.com useful to you, please consider making a donation. Use […]

The Original Sin
Disclaimer: What you are about to read may contain inaccuracies. Feel free to discuss them somewhere else. This is also my opinion and as such it may change through time, maybe tomorrow, next month, next year, next decade or never. I do also make very few reviews (if any) of what I write here so […]

Nmap cheatsheet
Nmap is a discovery tool used in security circles but very useful for network administrators or sysadmins. One can get information about operating systems, open ports, running apps with quite good accuracy. It can even be used in substitution to vulnerability scanners such as Nessus or OpenVAS for not very large environments, or quick audits. […]

How to mitigate DoS attacks with mod_evasive on FreeBSD
Denial of Service attacks or the distributed version of them (DDoS) have been growing throughout the years with their ups and downs. In my view the only thing that will happen to them is even bigger growth. With the advent of IoT devices the next decade will see an increase in these kind of attacks. […]
