Defend the Castle

You know them by name:  Ghost, Heartbleed, ShellShock, ImageTragick, StageFright. Vulnerabilities so big that even your boss is worried about them. Most of us are likely passingly familiar with these big-name vulnerabilities and how they work.

But have you ever actually seen exploits for these vulnerabilities? Do you know what they look like as they traverse our networks? Could you detect such an attack?
For those that think they could detect such an attack, could you block all the various forms an exploit could take?

Welcome to Defend the Castle – a contest for BlueTeamers

Contestants create their own signatures for network-based attacks against some of the most well-known, publicly-documented vulnerabilities (or exploit kits) of the recent past.

Contestant signatures will be tested against increasingly difficult-to-properly-detect attack traffic (exploit list below). But there’s a catch: You can’t be too aggressive—you’ll get penalized for blocking legitimate traffic (just like in the real world).

Be sure to pre-register for Defend the Castle to reserve your spot and make the most of it! Just use the Registration button to your right and fill in the details.

Goal of the Competition

/ Contestants will upload signatures to Intrusion Prevention System (IPS) of their choice (available devices below)

/ After network connectivity is verified, legitimate traffic must be allowed

/ no port- or protocol-based signatures

/ Signatures will then be tested against a multitude of exploit variants

/ Additional points available for specifically detecting threat

/ Signatures will then be tested against False Positive versions of the exploits (traffic that may be non-standard, but doesn’t actually exploit the vulnerability).

/ False Positives will lower your score

Can you protect the keys to your kingdom? Suitable prizes awarded for those who can.

/ Contestants are encouraged to research and create signatures ahead of time.
/ For those new to custom signature-development, signature templates will be available at the contest desk.

Rules of Engagement

/ 3 entry per person (1 file containing all signatures; format will vary based on IPS)

/ No port- or protocol-based signatures

/ Blocked/Allowed will be determined by testing device (not IPS)

/ Signatures must be intellectual property of contestant

/ Winning signatures must be available to the public after the close of the contest

/ Signature-based detection only; other IPS features will be disabled​


/ Points will be awarded based on the number of attacks blocked, with a multiplier based on difficulty.

/ Points will be subtracted based on the number of FalsePositives blocked, using the same multiplier.

/ In the event of a tie—at the discretion of the judges—additional points may be awarded based on style. Or they will be randomly selected.


Contestants submitting the 3 best-performing signatures will receive a prize.
Prizes are:

/ Amazon Kindle

/ Zeblaze Vibe 5

/ Redragon – S101-BA


Mihai Vasilescu – Principal Security Researcher –


List of exploits (with point multiplier; participants can attempt them in any order):

  • CVE-2021-5902 – F5 Big-IP multiple vulnerabilities – 10 points
  • CVE-2021-25646 – Apache Druid RCE – 10 points
  • CVE-2021-26084 – Confluence RCE – 20 points
  • CVE-2020=16846 – SaltStack Salt API command injection – 20 points
  • CVE-2020-1472 – Zerologon authentication bypass (over SMB) – 30 points
  • CVE-2021-34527 Microsoft Windows Print Spooler code execution (PrintNightmare) – 30 points

List of IPS devices available

  • Suricata


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Sponsors & Partners

They help us make this conference possible.


At Orange Business Services, we help our customers transform their industries, reimagine their services, create a positive impact and unleash the power of their data into an amazing and trusted resource.

With the dual expertise as a global operator coupled with the agility of an end-to-end integrator, Orange Business Services is a global network-native, digital services company. From connectivity, smart mobility services and the cloud to artificial intelligence (AI), analytics and cybersecurity, Orange Business Services helps businesses at every stage of their data management. Orange Business Services is represented in Romania by the business division of Orange Romania and helps large companies, SMEs and public authorities to transform their organizations through the use of technology and digital information.

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