Security on Nico Maas

fail2ban Cheat Sheet

Wed, 17 Feb 2021 10:22:00 +0000

Just the commands I always need to look up, because I forgot again…

Overview over fail2ban status and jails

fail2ban-client status

See which e.g. IPs are banned for sshd jail

fail2ban-client status sshd

Unban an IP from sshd jail

fail2ban-client set sshd unbanip IPADDRESSHERE

See which systems are actually banned

zgrep 'Ban' /var/log/fail2ban.log*

Rogue One: My first field pentesting

Mon, 18 Dec 2017 19:34:57 +0000

Earlier that year, very - earlier - I had one technician of an international company calling me for some advice. She/He had a problem with the local networking staff and their “modus operandi” regarding network security. The company had a big assembly line and very powerful, automated machinery - which made the leaky security all the more troublesome. My job was to exploit one of those security holes and show - as clearly and easily as possible - said problems - so that they were getting finally fixed.

Gravatar considered harmful - disabling it on my blog

Mon, 06 Feb 2017 13:27:24 +0000

Due to the fact that Gravatar makes users very easily trackable (read r1ch.nets Post “Gravatar considered harmful”) I decided to remove the use of Gravatar from my blog. I did this be removing the feature in the Discussion Settings, as well as using the “Disable User Gravatar” plugin to prevent WordPress to leak your E-Mail address through your Gravatar on my blog.

[Ubuntu] Secure your Apache 2 Reverse Proxy

Mon, 12 Sep 2016 10:36:40 +0000

We got an Apache 2, working as Reverse Proxy to some Docker instances (we won’t talk about the nginx vs Apache stuff here for the same reasons we won’t talk about vi vs emacs vs xyz ;)) - and somehow we realized that our apps are a little bit too sensitive to allow them from any ip.

First, we want to activate the needed modules. Normally that should not be necessary, but for sake of completeness:

[Security] BetterCrypto.org - Applied Crypto Hardening

Fri, 03 Jan 2014 20:45:57 +0000

So, now something a little bit more personal: We all know about the problems in our modern world: NSA, espionage, data stealing / selling, and such. We all use computer systems on an daily base and we know about the importance of cryptography. BUT: We don’t really all have an masters degree in computer crypto or such. We all do things in a “well, should be quite right”-way. Because, well - we have a life and a lot of stuff to do. We can’t really tell apart which ciffer to use and such. But now - we don’t need to - anymore. Please visit https://bettercrypto.org/ and read their paper. It got excellent “Copy ’n Paste” configuration commands for your Apache, Postfix, Mail, etc, etc!

Java 7 Update 11 Hotfix

Mon, 14 Jan 2013 11:33:32 +0000

The Java 7 Update 11 has been released by Oracle. You should make sure to download it from http://www.java.com/download asap.

Ubuntu 10.04 - Install Madwifi and Aircrack-ng

Sun, 03 Oct 2010 17:08:15 +0000

PreWork:

apt-get update  
apt-get install build-essential  
apt-get install libssl-dev

Install Madwifi for AR5007EG / AR5001

# Download latest from http://snapshots.madwifi-project.org/madwifi-hal-0.10.5.6/  
tar -xvzf madwifi-hal-0.10.5.6-r4126-20100324.tar.gz  
cd madwifi-hal-0.10.5.6-r4126-20100324  
make  
make install  
# System, Hardware Driver, mark "Activate Alternate Drivers"  
reboot

Install latest Aircrack-ng

# Download latest from http://www.aircrack-ng.org/  
# i.e. wget http://download.aircrack-ng.org/aircrack-ng-1.1.tar.gz  
tar -xvzf aircrack-ng-1.1.tar.gz  
cd aircrack-ng-1.1  
make  
make install

Lets go! ^^

Iptables Basic Introduction

Wed, 17 Feb 2010 13:36:01 +0000

Iptables are the Firewall of many Unix based Systems. Its quite easy to install and more easy to manage than most ppl would think of. Lately I became the SysAdmin of an Linux based Root Server and wanted to secure it as much as possible. So I went for my first exercise with Iptables and found that they are quite to manage as long as you know some important things.

Astaro Security Gateway v7 Factory Reset

Fri, 17 Jul 2009 22:42:15 +0000

Access to SSH or console with root passwords:

/etc/init.d/factoryreset reset

No Access to SSH or root passwords are lost:

Connect a keyboard and monitor to the system.
Wait for boot prompt
Enter:

boot: default factoryreset

After that you can go to your during the installation definied IP like: https://192.168.0.1

Alternativ:

Boot on the ASG from a Knoppix CD
Login as root
Mount the root partition of the ASG with: mount –t ext3 /dev/sda7 /mnt
Go to the config on the ASG: cd /mnt/etc/wfe/conf/; vim setting
Change reset_pwd = 0 to reset_pwd = 1
Save
Run cd /; umount /mnt; reboot
Access the install IP

Astaro Security Gateway c't Version

Fri, 17 Jul 2009 07:40:37 +0000

Free Home User License with 25 IPs!

http://www.astaro.de/unsere_produkte/produktueberblick/landing_pages/ct_special#license