tag: linux

Malware on the Wire: Monitoring Network Traffic with Suricata and ClamAV

19 Jun, 2020 - 6 minutes
In my endless quest to essentially create a Cisco Firepower firewall for poor people, I found a bit of a gap in the open source security ecosystem. While we have great tools for detecting malicious network traffic patterns, we don’t have easy ways of detecting malicious files in transit. So, a bit of fiddling around later, and I have a fairly basic system for integrating Suricata’s ‘filestore’ functionality with ClamAV’s real time scanning, thereby producing a log containing the source and destination addresses of any malicious files detected.

Cloud Threat Protection with OSSEC and Suricata

19 May, 2020 - 11 minutes
The idea of this setup is to protect the Small Systems as well as we protect the Big Systems. This solution uses a proven stack to protect webservers from modern threats. Using OSSEC, Suricata, and the built-in firewall capabilities of a modern Linux system it is possible to build a low maintenance and stable threat protection platform with relatively low performance impacts. It’s been specifically designed to be simple. The idea is that it will keep you on a ‘need to know basis’ and otherwise stay quiet and do it’s job.

Being Attacked by Bots

18 Feb, 2020 - 6 minutes
On the 19th of January 2020, a malicious actor launched an attack against my home infrastructure. At 42 minutes after midnight a device located in Buenos Aires, Argentina began attacking my proxy server. For the next six minutes, approximately 150 malicious HTTP requests were made. Fortunately, every single one of these requests was met with a HTTP/400 response, that’s because I don’t use Apache Struts 2 which this bot was attempting to exploit.

Build a Linux Router from an Old Laptop

13 Nov, 2019 - 7 minutes
Recently, I found myself in a situation where I needed to quickly replace a broken router. In times like these, you must improvise and think on your feet… The device in question was an old, rusty but trusty IBM ThinkPad T60. This particular machine has a special history for me. I salvaged it from a pile of e-waste at my old job as a PC tech many years ago, and that summer it was my playground for learning Linux ultimately starting the career which I currently enjoy.

Fix an Oversharded Elasticsearch Cluster

TL;DR The default settings for Logstash index rotation are bad and will break your cluster after a few months unless you change the rotation strategy. If you’re anything like me, you probably read somebody’s cool blog about how awesome ELK stack is and just had to have a piece of it. So you went through the quick start guide, googled your way through getting it up and running, then BAM you had an awesome logging system with all the bells and whistles!

Automating KVM Virtualization

Think of it like, “OpenStack for cheapskates." There are plenty of ways to automate the provisioning of virtual machines, and while this isn’t the best way it certainly works great for me. I am fortunate enough to have a very heterogeneous environment at home; aside from a few appliances nearly all my virtual machines are running Ubuntu 18.04. This approach certainly won’t work for those who have a mixed environment with different versions Linux, Windows, and BSD derivatives.

Cleanup Systemd Journald Storage

9 Jul, 2019 - 2 minutes
With the move from sysvinit to systemd, there were lots of small but important changes to the Linux ecosystem. One of them was the move from traditional syslog daemons to Systemd Journald. Now I’m not going to say this is a good or bad thing, as it entirely depends on your old habits and new optimism. What it does mean is a move to a faster and more flexible system log format but at the cost of some added complexity.

Clustering KVM with Ceph Storage

4 Mar, 2019 - 12 minutes
I have, for a long time, been fascinated and terrified by “Virtual SAN” solutions. The idea of combining storage and compute seems on the surface very attractive. It allows us to scale out our storage and compute together or separately in relatively small and affordable units, helping avoid the sticker shock of the upfront cost of storage systems. And as somebody especially prone to capex-phobia, that really is a great solution.

Deploy MDT Litetouch on Linux with TFTPD and Syslinux

4 Oct, 2018 - 5 minutes
No, I would not like to say hello, Cortana. Nothing is as monotonous, boring, and brain-numbingly automatable as installing Windows, installing applications, joining a domain, and clicking all the right boxes in all the right places. And it’s even worse in the latest versions of Windows 10, where we’re greeted by the condescending robot voice of Halo’s deceptive antagonist artificial intelligence during the OOBE setup phase. I’ve taken a particular liking to MDT, Microsoft’s solution to the absolute eye-glazing snorefest of configuring a new workstation or server.