What the hack? – or how my first capture the flag went

The 2017 BSides Security Conference, just outside of Ottawa, was a two day event from October 5th to 6th. It was packed with talks, lock picking, and a capture the flag (CTF) competition. Pretty great for being a free conference.

On the second day of the conference I decided to join one of the Shopify CTF teams since it looked like a ton of fun. Actually, I think it was the deep house playing 24/7 was what lured me into the dim and crowded CTF room of the conference centre. I subbed in for one of my friends on Shopify’s Red Team, which was suitably named for Shopify’s second CTF team. Shopify’s first team was named the Blue Team.

I thought I knew what CTF’s were all about – hacking challenges, they say. But I was completely unprepared. My “so called” 10+ years of listening to the Security Now podcast didn’t exactly prepare me for the hands-on experience required for CTFs. It was quite the learning experience since most of the flags remaining on day 2 were difficult to capture for a newbie.

Having some of a background in security and hacking helps, though it doesn’t bridge the gap between the hacking experience and intuition required to solve CTF challenges. These challenges require experience and practice in thinking like an attacker.

For example, it’s one thing to understand that data can be hidden in images via steganography, but it’s another thing completely to actually extract the hidden data from an image.

Instead of wasting time on finding unknown flags, I focused on the topics I have experience with. Most of the flags I focused on were WEP and WPA cracking with aircrack-ng, and it’s associated collection tools. I was not able to inject packets with my setup, but luckily some other competitors did the hard work for me. After a few hours of unsuccessful attempts to crack the Wi-Fi networks I conceded that my attempts weren’t working.

I moved onto a new flag that involved breaking into an old exploited version of Joomla. After asking for some help from a teammate we found a script on exploit-db that would raise privileges to admin for any user. After running the exploit it took me a bit to figure out that it ran successfully since the flag was locked inside a Page that was locked for editing by someone else. The ‘locked for editing’ didn’t allow reading the Page, but after figuring out that the Page had a context menu to unlock it enabled me to view the flag. That made me facepalm both at Joomla’s UI and my inability to figure that out sooner.

After a day filled with a of couple muffins, a few slices of pizza, and countless teas the CTF concluded around 5pm. Winners were announced and thankfully our team didn’t fail too hard. I came out of the competition having met a bunch of colleagues from different parts of the company, and the expectation of what to expect in future CTFs. I’ll definitely be attending another CTF.

My team, the Red-Team, placed somewhere around 5th or 6th. Not too bad for having a handicap on it like myself. I got to hand it to Shopify, they have some seriously talented Security folks! No wonder Shopify’s Blue-Team came in first!

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Jon Simpson

I’m a software engineering professional interested in Continuous Delivery, Lean, hipster programming languages, and distributed computing. In my spare time I enjoy reading books, tasting craft beers, and exploring Canada’s capital. I have a Bachelors of Computer Science with a specialization in Network Computing from Carleton University, Ottawa.

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