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CTF players versus professional penetration testers

Sep 02, 20156 mins
CareersGovernmentIT Jobs

CTF players or professional penetration testers - who can bring more value to your business?

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According to ISACA’s State of Cybersecurity: Implications for 2015 report, 72.33% of respondents said that the biggest skill gap in today’s security professionals is ability to understand the business.

Another interesting fact from the survey is that the majority of respondents found that less than 25% of applicants were qualified for a cybersecurity position. These numbers highlight a very serious gap between people looking for an infosec job and modern businesses. Actually, a similar gap exists between CTF contests and professional penetration testing.

Unlike when I was a student, today one can easily find a great variety of CTF events of all sorts and types, from the easiest tasks to complicated reverse and crypto challenges. However, many CTFs are organized by security enthusiasts and their main audience are students or newbies who want to try their offensive security skills in the wild without breaking the law.

Even at famous CTF events, usually organized in parallel with various conferences, many CTF players are students or have just started their first infosec job. Sadly, quite often prominent teams of young but talented players fail to participate in a CTF due to the high price of travel and the events being held in venues they simply cannot afford.

This is why online CTFs have become more and more popular. Many security companies of different sizes organize or sponsor CTFs in order to attract media attention and recruit the most prominent players. Let’s try to understand what impact CTF experience may have on one’s habitudes, technical skills and cybersecurity career.

Yan Borboën, Partner at PwC Switzerland, MSc, CISA, CRISC, shared his opinion about the subject: “With the increasing number of attacks in the world, companies need to recruit well trained people. CTF is an extraordinary game field for people to train and to demonstrate their motivation.

At PwC, we sponsor security competition as Swiss Cyber Storm Security challenge because it is clearly an opportunity to identify and recruit talent. However, technical capabilities is only one aspect of a penetration test and will provide assurance against common everyday attacks, they do not provide assurance against more sophisticated and persistent attacks.

To provide real value to our client, we would rather recommend intelligence led security testing (e.g. CREST STAR), which incorporates threat intelligence and penetration testing to replicate accurately a full scenario of a targeted attack against an entire organisation including people, processes and technologies.”

During weekends, I like reading CTF write-ups from time to time, especially those that cover web security challenges. However, I remember very few of them covered real business case scenarios that professional penetration testers face every day.

I obviously omit sophisticated crypto challenges, car hacking, phreaking, ATM hacking and non-security challenges that CTF organizers set up to bring some fun to the event. But even the remaining part is still pretty far from daily reality. So, what is the practical difference between CTF and penetration testing, and what impact can it have on a business?

The first issue with the majority of CTFs is that they usually focus on a single result (flags), rather than a process of comprehensive consecutive security testing. I saw many cases when a penetration test, conducted by CTF players, consisted of exploiting one single vulnerability to facilitate exploitation of all others.

The upcoming report contained quite irrelevant information, such as demonstration of web application source code and databases obtained via brute-forced FTP password or arbitrary file upload vulnerability.

At the same time simple SQL injection vulnerabilities in web services were not even mentioned in the report, as penetration testers considered that ‘capturing the flag’ via getting all confidential information from the server is enough to impress the customer. In reality, very few customers are ready to pay for such service, as it has very low (if any) value from the business’ point of view.

The second concern is that very few CTFs offer technical infrastructure similar to a real business environment. CTF is about hacking a deliberately insecure system intentionally left vulnerable, while a penetration test is about testing a complicated system that a team of cybersecurity professionals tries to keep secure.

The way of thinking during a CTF and a penetration test is totally different. Being in a ‘pentest mode’ you will hardly solve even the easiest CTF challenge and vice-versa. During a CTF you usually look for direct or indirect hints, or try to understand and predict the logic of the task’s creator, while during a penetration test you need to entirely understand business logic, global cybersecurity vision and defense strategy of your customer.

The next problem one may face with CTF gurus is the security tester’s responsibility when selecting attack methodologies and techniques. What would happen during a CTF if you suddenly or deliberately crash the system with unstable exploit, making others unable to test it? In the worst case, your team would lose some scoring points.

During a penetration test, such imprudence may cost your customer millions of dollars. I personally saw web shells left on customer’s website after a penetration test, as nobody bothered to remove them after “capturing the flag”. The similar problem of bad habitudes also exists in many other domains, for example some car racing games provoke imprudent driving in reality.

Scope of testing is also very important issue: at High-Tech Bridge for almost every penetration test, we have some special business requirements in terms of scope and perimeter of testing. A penetration test is process oriented, while CTF is mainly result oriented.

Customers are usually aware that, for various business and operational reasons, some components of their IT infrastructure are vulnerable, and they are not ready to pay to have that fact reported on paper. Instead,- they hire us to test the resistance of the secure part of their infrastructure, while patching or migrating the vulnerable ones.

For a penetration test, it is very important to clearly define what to test and how to test, otherwise you will likely just irritate your customer. I saw several cases when CTF players were not able to control their behavior during a penetration test attacking the client from all sides, as they used to have ‘no limits’ taking the entire process as a game. Despite the “got root” results they had, their customers were about to sue them for attacking wrong systems.

Therefore, when hiring a new team player, I would definitely prefer an experienced penetration tester to a CTF champion. However, with all other equals, a CTF experience may definitely be a good added-value. CTF helps to develop and to perfect stand-alone technical skills and exploitation techniques.

A CTF player can also bring some useful insights to your team and a vision from a different angle that others will probably not have.

Nevertheless, we should always keep in mind that CTF is a game, while penetration testing is a serious business, and we shall not mélange them.


Ilia Kolochenko is a Swiss application security expert and entrepreneur. Ilia holds a BS (Hons.) in Mathematics and Computer Science, and is currently performing his Master of Legal Studies degree at Washington University in St. Louis.

Starting his career as a penetration tester, he later founded web security company High-Tech Bridge, headquartered in Geneva. Under his management, High-Tech Bridge won SC Awards Europe 2017 and was named a Gartner Cool Vendor 2017 among numerous other prestigious awards for innovation in application security and machine learning.

Ilia is a contributing writer for SC Magazine UK, Dark Reading and Forbes, mainly writing about cybercrime and application security. He is also a member of the Forbes Technology Council.

The opinions expressed in this blog are those of Ilia Kolochenko and do not necessarily represent those of IDG Communications, Inc., its parent, subsidiary or affiliated companies.