I’ve just written a post for the BSidesSF blog about running the BSidesSF 2019 CTF. Check it out and feel free to get in touch if you have feedback.

Flagsrv was a 300 point web challenge in this year’s BSidesSF CTF. The description was a simple one:

We’ve built a service for the sole purpose of serving up flags!

The account you want is named ‘flag’.

The Challenge

Sometimes you see marketing materials that use the word cloud to the point that it starts to lose all meaning. This service allows you to fix that with clowns instead of clouds. Note: there are 2 flags, they should be clearly labeled.

A recent conversation with a coworker inspired me to start putting together a series of blog posts to examine what it is that shellcode does. In the first installment, I’ll dissect the basic reverse shell.

First, a couple of reminders: shellcode is the machine code that is injected into the flow of a program as the result of an exploit. It generally must be position independent as you can’t usually control where it will be loaded in memory. A reverse shell initiates a TCP connection from the compromised host back to a host under the control of the attacker. It then launches a shell with which the attacker can interact.

At DerbyCon 8, I had the opportunity to take the “Adversarial Attacks and Hunt Teaming” presented by Ben Ten and Larry Spohn from TrustedSec. I went into the course hoping to get a refresher on the latest techniques for Windows domains (I do mostly Linux, IoT & Web Apps at work) as well as to get a better understanding of how hunt teaming is done. (As a Red Teamer, I feel understanding the work done by the blue team is critical to better success and reducing detection.)