1. What is Cryptography? Cryptography is the practice and study of techniques for securing information and communication mainly to protect the data from third parties that the data is not intended for. 2. What is the difference between Symmetric and Asymmetric encryption? Basis of Comparison Symmetric Encryption Asymmetric Encryption Encryption key Same key for encryption & decryption Different keys for encryption & decryption Performance Encryption is fast but more vulnerable Encryption is slow due to high computation Algorithms DES, 3DES, AES and RC4 Diffie-Hellman, RSA Purpose Used for bulk data transmission Often used for securely exchanging secret keys 3. What is the difference between IDS and IPS? IDS is Intrusion Detection System and it only detects intrusions and the administrator has to take care of preventing the intrusion. Whereas, in IPS i.e., Intrusion Prevention System, the system detects the intrusion and also takes actions to prevent the intrusion. 4. Explain CIA triad. CIA stands for Confidentiality, Integrity, and Availability. CIA is a model that is designed to guide policies for Information Security. It is one of the most popular models used by organizations. Confidentiality The information should be accessible and readable only to authorized personnel. It should not be accessible by unauthorized personnel. The information should be strongly encrypted just in case someone uses hacking to access the data so that even if the data is accessed, it is not readable or understandable. Integrity Making sure the data has not been modified by an unauthorized entity. Integrity ensures that data is not corrupted or modified by unauthorized personnel. If an authorized individual/system is trying to modify the data and the modification wasn’t successful, then the data should be reversed back and should not be corrupted. Availability The data should be available to the user whenever the user requires it. Maintaining of Hardware, upgrading regularly, Data Backups and Recovery, Network Bottlenecks should be taken care of. 5. How is Encryption different from Hashing? Both Encryption and Hashing are used to convert readable data into an unreadable format. The difference is that the encrypted data can be converted back to original data by the process of decryption but the hashed data cannot be converted back to original data. 6. What is a Firewall and why is it used? A Firewall is a network security system set on the boundaries of the system/network that monitors and controls network traffic. Firewalls are mainly used to protect the system/network from viruses, worms, malware, etc. Firewalls can also be to prevent remote access and content filtering. 7. What is the difference between VA(Vulnerability Assessment) and PT(Penetration Testing)? Vulnerability Assessment is the process of finding flaws on the target. Here, the organization knows that their system/network has flaws or weaknesses and want to find these flaws and prioritize the flaws for fixing. Penetration Testing is the process of finding vulnerabilities on the target. In this case, the organization would have set up all the security measures they could think of and would want to test if there is any other way that their system/network can be hacked. 8. What is a three-way handshake? A three-way handshake is a method used in a TCP/IP network to create a connection between a host and a client. It’s called a three-way handshake because it is a three-step method in which the client and server exchanges packets. The three steps are as follows: The client sends a SYN(Synchronize) packet to the server check if the server is up or has open ports The server sends SYN-ACK packet to the client if it has open ports The client acknowledges this and sends an ACK(Acknowledgment) packet back to the server 9. What are the response codes that can be received from a Web Application? 1xx – Informational responses 2xx – Success 3xx – Redirection 4xx – Client-side error 5xx – Server-side error 10. What is traceroute? Why is it used? Traceroute is a tool that shows the path of a packet. It lists all the points (mainly routers) that the packet passes through. This is used mostly when the packet is not reaching its destination. Traceroute is used to check where the connection stops or breaks to identify the point of failure. 11. What is the difference between HIDS and NIDS? HIDS(Host IDS) and NIDS(Network IDS) are both Intrusion Detection System and work for the same purpose i.e., to detect the intrusions. The only difference is that the HIDS is set up on a particular host/device. It monitors the traffic of a particular device and suspicious system activities. On the other hand, NIDS is set up on a network. It monitors traffic of all device of the network. 12. What are the steps to set up a firewall? Following are the steps to set up a firewall: Username/password: modify the default password for a firewall device Remote administration: Disable the feature of the remote administration Port forwarding: Configure appropriate port forwarding for certain applications to work properly, such as a web server or FTP server DHCP server: Installing a firewall on a network with an existing DHCP server will cause conflict unless the firewall’s DHCP is disabled Logging: To troubleshoot firewall issues or potential attacks, ensure that logging is enabled and understand how to view logs Policies: You should have solid security policies in place and make sure that the firewall is configured to enforce those policies. 13. Explain SSL Encryption SSL(Secure Sockets Layer) is the industry-standard security technology creating encrypted connections between Web Server and a Browser. This is used to maintain data privacy and to protect the information in online transactions. The steps for establishing an SSL connection is as follows: A browser tries to connect to the webserver secured with SSL The browser sends a copy of its SSL certificate to the browser The browser checks if the SSL certificate is trustworthy or not. If it is trustworthy, then the browser sends a message to the web server requesting to establish an encrypted connection The web server sends an acknowledgment to start an SSL encrypted connection SSL encrypted communication takes place between the browser and the web server 14. What steps will you take to secure a server? Secure servers use the Secure Sockets Layer (SSL) protocol for data encryption and decryption to protect data from unauthorized interception. Here are four simple ways to secure server: Step 1: Make sure you have a secure password for your root and administrator users Step 2: The next thing you need to do is make new users on your system. These will be the users you use to manage the system Step 3: Remove remote access from the default root/administrator accounts Step 4: The next step is to configure your firewall rules for remote access 15. Explain Data Leakage Data Leakage is an intentional or unintentional transmission of data from within the organization to an external unauthorized destination. It is the disclosure of confidential information to an unauthorized entity. Data Leakage can be divided into 3 categories based on how it happens: Accidental Breach: An entity unintentionally send data to an unauthorized person due to a fault or a blunder Intentional Breach: The authorized entity sends data to an unauthorized entity on purpose System Hack: Hacking techniques are used to cause data leakage Data Leakage can be prevented by using tools, software, and strategies known as DLP(Data Leakage Prevention) Tools. 16. What are some of the common Cyberattacks? Following are some common cyber attacks that could adversely affect your system. common cyber threats-cybersecurity interview questions-edureka 17. What is a Brute Force Attack? How can you prevent it? Brute Force is a way of finding out the right credentials by repetitively trying all the permutations and combinations of possible credentials. In most cases, brute force attacks are automated where the tool/software automatically tries to login with a list of credentials. There are various ways to prevent Brute Force attacks. Some of them are: Password Length: You can set a minimum length for password. The lengthier the password, the harder it is to find. Password Complexity: Including different formats of characters in the password makes brute force attacks harder. Using alpha-numeric passwords along with special characters, and upper and lower case characters increase the password complexity making it difficult to be cracked. Limiting Login Attempts: Set a limit on login failures. For example, you can set the limit on login failures as 3. So, when there are 3 consecutive login failures, restrict the user from logging in for some time, or send an Email or OTP to use to log in the next time. Because brute force is an automated process, limiting login attempts will break the brute force process. 18. What is Port Scanning? Port Scanning is the technique used to identify open ports and service available on a host. Hackers use port scanning to find information that can be helpful to exploit vulnerabilities. Administrators use Port Scanning to verify the security policies of the network. Some of the common Port Scanning Techniques are: Ping Scan TCP Half-Open TCP Connect UDP Stealth Scanning 19. What are the different layers of the OSI model? An OSI model is a reference model for how applications communicate over a network. The purpose of an OSI reference is to guide vendors and developers so the digital communication products and software programs can interoperate. Following are the OSI layers: different OSI layers-cybersecurity interview questions-edureka Physical Layer: Responsible for transmission of digital data from sender to receiver through the communication media, Data Link Layer: Handles the movement of data to and from the physical link. It is also responsible for encoding and decoding of data bits. Network Layer: Responsible for packet forwarding and providing routing paths for network communication. Transport Layer: Responsible for end-to-end communication over the network. It splits the data from the above layer and passes it to the Network Layer and then ensures that all the data has successfully reached at the receiver’s end. Session Layer: Controls connection between the sender and the receiver. It is responsible for starting, ending, and managing the session and establishing, maintaining and synchronizing interaction between the sender and the receiver. Presentation Layer: It deals with presenting the data in a proper format and data structure instead of sending raw datagrams or packets. Application Layer: It provides an interface between the application and the network. It focuses on process-to-process communication and provides a communication interface. 20. What is a VPN? VPN stands for Virtual Private Network. It is used to create a safe and encrypted connection. When you use a VPN, the data from the client is sent to a point in the VPN where it is encrypted and then sent through the internet to another point. At this point, the data is decrypted and sent to the server. When the server sends a response, the response is sent to a point in the VPN where it is encrypted and this encrypted data is sent to another point in the VPN where it is decrypted. And finally, the decrypted data is sent to the client. The whole point of using a VPN is to ensure encrypted data transfer. 21. What do you understand by Risk, Vulnerability & Threat in a network? Threat: Someone with the potential to harm a system or an organization Vulnerability: Weakness in a system that can be exploited by a potential hacker Risk: Potential for loss or damage when threat exploits a vulnerability 22. How can identity theft be prevented? Here’s what you can do to prevent identity theft: Ensure strong and unique password Avoid sharing confidential information online, especially on social media Shop from known and trusted websites Use the latest version of the browsers Install advanced malware and spyware tools Use specialized security solutions against financial data Always update your system and the software Protect your SSN (Social Security Number) 23. What are black hat, white hat and grey hat hackers? Black hat hackers are known for having vast knowledge about breaking into computer networks. They can write malware which can be used to gain access to these systems. This type of hackers misuse their skills to steal information or use the hacked system for malicious purpose. White hat hackers use their powers for good deeds and so they are also called Ethical Hackers. These are mostly hired by companies as a security specialist that attempts to find and fix vulnerabilities and security holes in the systems. They use their skills to help make the security better. Grey hat hackers are an amalgamation of a white hat and black hat hacker. They look for system vulnerabilities without the owner’s permission. If they find any vulnerabilities, they report it to the owner. Unlike Black hat hackers, they do not exploit the vulnerabilities found. 24. How often should you perform Patch management? Patch management should be done as soon as it is released. For windows, once the patch is released it should be applied to all machines, not later than one month. Same goes for network devices, patch it as soon as it is released. Proper patch management should be followed. 25. How would you reset a password-protected BIOS configuration? Since BIOS is a pre-boot system it has its own storage mechanism for settings and preferences. A simple way to reset is by popping out the CMOS battery so that the memory storing the settings lose its power supply and as a result, it will lose its setting.