20 Interview Questions and Answers for Cyber-security Professionals
Interviewing and hiring cybersecurity professionals can be more difficult than other types of technology professionals. Unless the hire is for a specific skill, like configuring routers or other appliances, a successful cybersecurity professional has to understand a wide variety of technology, be intellectually curious, and trustworthy.
[Related reading: The State of the Cybersecurity Market by 2020]
As someone with years of experience in the cyber-security space, I’ve interviewed hundreds of prospective applicants for roles ranging from network security specialist to senior executive positions for large IT security multinational organizations.
In this article, I touch upon 20 important questions that aspiring cyber security professionals are likely to face in an interview – and which responses are the most effective.
Cyber-Security Interviews: Insights into the Interviewer’s Mind
Interviewers would generally want to avoid blasé, typical questions that a candidate would have been able to practice, especially if they have been professionally coached while covering the major cybersecurity topics. Rather than start with asking for the usual short biography, these days most interviewers open with prompting the interviewee to -
“Tell me about your home network.”
Although there is no right answer for this question, it helps the candidate relax, while pushing them off script. From there, try probing into details and ask relevant questions about decisions.
Understanding how a person thinks about cybersecurity is just as important as knowing about the controls. Following the discussion as to why the candidate made specific decisions, you are likely to be asked, “What is the goal of information security within an organization?”
This helps the interviewer understand what you think about the role. Are you authoritarian and will be ready to stop the project because of a risk or is there a better way? This will also help them answer if the applicant is trustworthy.
“What is the difference between a threat, vulnerability, and a risk?”
Any cyber-security professional worth their salt would know the answer to this one. This is better than asking about your definition of cybersecurity because a good answer to this question calls for a deep understanding of the nature of cybersecurity.
One of the best answers I’ve received for this question was as follows - “A threat is from an attacker that will use a vulnerability that was not mitigated because someone forgot to identify it as a risk.” A good follow up would be to ask, “What is more important for cybersecurity professionals to focus on, threats or vulnerabilities?”, so expect to be prepared for this question as well.
At this point, as interviewee, you would either be very relaxed or very nervous. The nervous candidate may be qualified but, depending on answers to the opening questions, may not be the right candidate. For both types of candidates, moving to a more technical discussion will help the interviewer better understand how their minds can handle a change of direction.
In this phase, I would typically start off with a question like, “What are your first three steps when securing a server?” If the enterprise uses a particular type of server, like Windows Server or Linux, they will make the question more specific to your experience and expertise. Although there could be many right answers, the objective of this question is to gain an insight into your thought processes and decision-making ability.
Good answers to this one involve evoking the Principle of Least Privilege or the concept of Trust No One (TNO). Expect variations on this question, such as “Do you prefer filtered ports or closed ports on your firewall?” The intent here is to gauge the depth of your knowledge and expertise in cross-domain risk mitigation.
Cybersecurity monitoring questions are my favorites. “Why is DNS monitoring important?” Almost any answer other than an admission of not being necessary would indicate an understanding that there are weaknesses in the domain name services. Expect the interviewer to follow this up with a question to catch you off guard - “What port does ping work over?” Ping uses the ICMP ECHO facilities in Layer 3 and any other answer would not be correct. I’d round this off with, “How does traceroute, or tracert under Windows, work and why would it be used?”
Continuing with the network-based discussion, another good interview question would be “What could you do to prevent a man-in-the-middle attack?” The expectation here is that this leading question should foster a healthy discussion about encryption. Rather than ask about the mechanics of encryption –which you will have a prepared answer for - a good question to ask would be “What’s the difference between encoding, encryption, and hashing?”
A cybersecurity profession must understand the differences in how network-related protocols are used in order to be able to understand the risks. A probing question like “Which is the most secure - SSL, TLS or HTTPS?” will allow you to demonstrate whether you recognize the differences.
By this time, the interviewer would have made up their mind as to whether you would be a good fit for the role and the organization. Expect questions on implementation issues, at this stage. “If you had to both encrypt and compress data during transmission, which would you do first, and why?” The short answer would be to compress then encrypt because the “noise” created by the encryption would be too random for compression to have an appreciable effect.
From a fun exercise, it’s time to answer a serious question about a serious problem - “What exactly is Cross Site Scripting?” This a vexing question because most people I’ve interviewed cannot answer the question, and this includes some who have sat for certification exams. A cybersecurity analyst must be able to answer this question and the follow up, “What are the common defenses against a Cross Site Scripting attack?” In today’s world, there are many who feel that a cyber-security professional who cannot answer this question satisfactorily is in need of a skill upgrade.
Now that the interview has transitioned to application and user security, expect questions like “How would you harden user authentication?” Although there are many good answers, the interviewer is specifically looking for mention of two-factor authentication or non-repudiation. To see if you really understand these concepts, they are likely to pose such application-related questions as “How would you implement two-factor authentication for a public-facing website?”
Public-facing websites can also be part of cloud services. To find out if the candidate knows whether there are differences in the risks between cybersecurity in the cloud versus on premises, I would ask, “Are there any special considerations for securing services in the cloud?” The purpose is to open the discussion so that the candidate has the opportunity to explain the differences. A lot can be learned from how the candidate answers this question, including whether they understand the special risks of using cloud-based services.
Many of the issues with deploying systems to the cloud or even on-premises can lead to conflicts among the stakeholders. Cybersecurity professionals must be able to work with the stakeholders while trying to mitigate the risks as much as tolerable. To understand how the candidate would work in this environment, an interviewer is likely to ask you “How would you balance demands from different stakeholders who have conflicting requirements?” Remember, your cybersecurity department is also a stakeholder and must be included in your answer.
Finally, continuous learning is a big part of making it as a cyber-security professional. If you are asked “Where do you get your cybersecurity news?”, do not expect to get away with generic answers. List out the websites you regularly visit, the mailing lists you are subscribed to. Make sure you are up to speed on the latest points of conversation on these forums so you can hold your own even if the interviewer decides to dig a little deeper.
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Cyber-Security Interview Questions – Distribution of Topics
Summary of Interview Questions for Cyber-security Interviews
Learning More about the Professional
- Tell me about your home network.
- What is the goal of information security within an organization?
- What is the difference between a threat, vulnerability, and a risk?
- What is more important for cybersecurity professionals to focus on, threats or vulnerabilities?
- What are your first three steps when securing a Linux server?
- Do you prefer filtered ports or closed ports on your firewall?
Operations and Monitoring
- Why is DNS monitoring important?
- What port does ping work over?
- How exactly does traceroute/tracert work at the protocol level?
- What could you do to prevent a man-in-the-middle attack?
- What’s the difference between encoding, encryption, and hashing?
- What’s more secure, SSL or HTTPS?
Application (Web) Security
- If you had to both encrypt and compress data during transmission, which would you do first, and why?
- What exactly is Cross Site Scripting?
- What are the common defenses against a Cross Site Scripting attack?
- How would you harden user authentication?
- How would you implement two-factor authentication for a public-facing website.
- Are there any special considerations for securing services in the cloud?
- How would you balance demands from different stakeholders who have conflicting requirements?
- Where do you get your cybersecurity news?
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