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Welcome!

I’m Koen . I live in Bruges (Belgium), a splendid medieval city also known as the Venice of the North.

I’m involved with computer security and I work as a freelancer in incident response, incident coordination, threat intelligence, vulnerability management and security best practices. Basically all tasks related to managing a CSIRT / CERT (Computer Emergency Response Team).

My main interests in computers are security, web applications (PHP, MySQL, Apache), system administration and free software.

This site hosts a blog and I have a photo collection at Flickr.

I also have a site with (outdated) Linux information.

Latest posts

How to Leverage Log Services to Analyze C&C Traffic

I published an article on How to Leverage Log Services to Analyze C&C Traffic on the Security Intelligence blog.

This article describes what can cause C2 traffic, the different types of C2 traffic and what log sources that you can use to detect the C2 traffic caused by malware.

How to Defend With the Courses of Action Matrix and Indicator Lifecycle Management

I published an article on How to Defend With the Courses of Action Matrix and Indicator Lifecycle Management on the Security Intelligence blog.

This article describes the courses of action matrix to help you understand how to verify and validate indicators. The CoA matrix assists you in choosing the most useful action (“response”) to take with a an indicator.

Recover administrator password of a Windows VM

I run a lab with a couple of Windows VMs on different laptops via VMware Workstation (for Linux). Some of these machines are “vulnerable” Windows systems (check out Microsoft Evaluation Center). I pretty much always use the same password for the administrator account to make management easy. This is bad practice for a real-life environment, but the purpose of these machines is to get compromised anyway.

However, sometimes it might seem like a good ideaRead more.

How Pivoting Can Help Your Incident Response Process

I published an article on How Pivoting Can Help Your Incident Response Process on the Security Intelligence blog.

This article describes what pivoting is about (mostly from a point of view of a defender, or during incident response), how to evaluate and track the links that you found, what domains are most useful to use for pivoting and what data points you can use for pivoting.

BloodHound Active Directory queries for Defenders

Getting Active Directory security right can be a challenging task. Individual groups of computers or user privileges will most likely be properly configured but there are always some trade-offs that have to be made. Attackers will try to find an attack path by abusing the weaknesses that are caused by these trade-offs. Jumping from one host to another, compromising user accounts and abusing active sessions might get them to their final objectives. Whether this isRead more.

Security and MQTT

I recently had to explore MQTT. I had never heard of this protocol before. However some helpful resources provide a clear explanation what MQTT is about.

MQTT is a machine-to-machine (M2M)/”Internet of Things” connectivity protocol that uses a lightweight publish/subscribe messaging transport. MQTT works on top of TCP/IP and by default uses port tcp/1883.

A quick search on Shodan reveals that there are a lot of devices publicly available, primarily in the US and Asia.Read more.

How Can an ISAC Improve Cybersecurity and Resilience?

I published an article on IBM Security Intelligence on How Can an ISAC Improve Cybersecurity and Resilience?.

The article covers analysing the three common types of ISACs (information sharing and analysis centers), who creates ISACs, reasons for joining an ISAC and what drives ISACs.

RDP logs and incident response

Remote desktop protocol (RDP) is designed by Microsoft for remote management of Windows-based virtual desktops. It provides users a graphical interface to connect over the network to a remote computer. Having a remote access feature leaves the door open for attackers.

I’ll use this post to summarise some of the information and commands that I use when investigating an RDP incident.

Note that RDP connections are usually done via tcp/3389.

Investigating RDP goes best inRead more.