Day 2 of Competition

Day 2 of the competition started in the Bucharest’s Palace of the Parliament with an entirely new set of challenges for the teams to solve, with the previous day’s 18 challenges now closed for submissions.

The format of the challenges was largely the same as the previous day, covering a broad range of categories. This morning each team found an ESP8266 chip with an antenna on their tables. This is a so-called “hardware challenge” and required the contestants to reverse the custom wireless protocol being used by the chip. The team strategised and decided to leave this challenge aside, as it is not something anyone was familiar with.

On Day 2, one person from each team was required to present the solution to one of the challenges their team had solved on Day 1. They presented to 5 Jury members who scored each presenter on their speaking skills and the difficulty of the challenge. Ryan Harrison gave a charismatic presentation on how Ireland found a Python deserialization bug in the “Random Dice” challenge.

Ryan Harrison presenting how Ireland solved the “Random Dice” Python deserialization challenge.

Ireland was later announced as one of the Top 5 presentations who would present again at the end of the conference to all the contestants. Well done Ryan! That glorious Belfast accent won over the jury and earned the team a rakeload of points.

Ireland had made serious gains in the first few hours of Day 2, solving Cryptography (ECC & ElGamal) and Web (PHP) challenges, enabling the team to reach 10th ranking on the scoreboard on two occasions. Other challenges solved included Incident response and Log analysis (write-ups to come on this blog – stay tuned!).

At 4 pm the scoreboard was frozen, and the team began to feel the heat, as several teams around began celebrating very audibly as they submitted last minute flags. With 20 mins to spare, Ireland solved a C# reversing challenge correctly, and felt a touch of relief. With just 15 mins to go, the team finally had a correct method (on paper) to solve a block-cipher hash collision challenge. Unfortunately, the team was unable to implement the Python code required to solve it in time.

The competition ended just after 6 pm with sustained applause from all of the teams. The huge effort was over, and the teams were able to relax and socialise, sharing solutions with each other. A buffet dinner was laid on for the teams in the Crystal Ballroom. The Irish team, in typical fashion, led the after-party to the Oldtown of Bucharest.

With the scoreboard frozen, no-one knew how the final standings would end up, with the result to be announced at the awards ceremony on Day 3.

Frozen leaderboard (2 hours before end of competition:)

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