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 – [email protected]


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.


Orange Romania is the leader of the local telecom market and part of the Orange Group, one of the largest global telecommunications operators, connecting hundreds of millions of customers worldwide. With over 11 million customers and an annual turnover exceeding 1.5 billion euros, Orange Romania connects 1 in 2 Romanians and offers an extensive range of communication solutions to its customers, both individual users and companies, from basic services up to complete voice services, fixed and mobile data, TV services or smart home services, but also mobile financial services. Orange is also a leader in innovation investing yearly over 200 million euros in network infrastructure and R&D initiatives in Romania. In the past 3 years Orange has launched two 5G Labs in Bucharest and Iasi, that aim to support researchers, startups and companies to test their 5G solutions in advance. In addition, Orange is a long-term supporter of the startup ecosystem through the Orange Fab accelerator program designed to support entrepreneurs in the development of innovative products and their distribution locally and internationally. 

Orange Services was created in 2013 and is a 100% owned subsidiary of Orange Group. As a technology services company, our DNA is in IT, but our teams also work in other domains including mobile networks and a number of commercial and business functions. Orange Services is one of the largest technology hubs in the Orange Group, working internationally for both Orange corporate functions and country operations. Through a unique combination of cutting edge know-how and expertise, our teams provide a broad range of services: development and supervision of IT services in domains such as Big Data, Cloud, M2M, IoT, TV, Connected Objects; design and development of IT infrastructure and desktop solutions; testing & planning for mobile networks; implementation of supply chain solutions and also improvement of commercial & business performance including BI, CRM, Analytics, Digital learning and Customer Care. Visit us on LinkedIn.

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