Moonlighter Is the First Ever Space-Based Capture the Flag Target for DEF CON 31

Capture the Flag (CTF) competitions are popular at the DEF CON security conference. Teams compete to hack into a computer-based system to capture a secret or flag. However, at 2023's DEF CON 31, the Aerospace Village is hosting Hack-A-Sat 4 — the first ever CTF competition to occur IN SPACE!

Hack-A-Sat aims to help cybersecurity professionals develop the skills necessary to build more secure space systems. The previous three CTF contests simulated space applications. This year at DEF CON 31, the Aerospace Village hosts the fourth Hack-A-Sat competition featuring the Moonlighter satellite.

Moonlighter is a purpose-built 3U CubeSat satellite in low-earth orbit and is the first satellite ever for training cybersecurity skills on space-based hardware. The US Space Systems Command (SSC) and the US Air Force Research Laboratory (AFRL) worked jointly to build it.

It was launched on an ISS resupply mission on June 5th, 2023, and deployed about a month later on July 6th. Now, in August 2023, it is an active target for DEF CON 31.

Five teams are competing from Las Vegas to solve nine challenges. Two challenges focus on the ground stations, with the rest hosted on Moonlighter. These CTF teams qualified in an event earlier in 2023. Initially, there were 728 teams and 2,700 registered players across 58 countries.

Hacking an orbital target involves unique challenges for the CTF teams. For example, there are pre-defined windows where four ground stations can uplink or downlink with the satellite. So all of the teams' hacking activities must be scheduled before deployment. An added challenge is that after the scheduled deployment, the teams must wait for another orbital pass for a downlink window to learn if their attempts were successful!

The CTF challenges run through DEF CON 31. The organizers will announce (most of) the results on Sunday, August 13th, at 12pm PT.

To keep up with the competition, check out the Moonlighter status board. Check out the Hack-A-Sat website to learn more about the project, competition, and the CTF teams.