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31. What are the steps involved in hacking a server or network?

The following steps must be ensured in order to hack any server or network:

• Access your web server.  
• Use anonymous FTP to access this network to gather more information and scan ports.
• Pay attention to file sizes, open ports, and processes running on your system.  
• Run a few simple commands on your web server like “clear cache” or “delete all files” to highlight the data stored by the server behind these programs. This helps in obtaining more sensitive information that can be used in application-specific exploits.
• Connect to other sites on the same network, such as Facebook and Twitter, so that you can check the deleted data. Access the server using the conversion channel.
• Access internal network resources and data to gather more information. 
• Use Metasploit to gain remote access to these resources.

To know more about this topic please refer to the article: How to Hack a Web Server?

32. What are the various sniffing tools?

Lists of some main Networking Sniffing Tools:

• Auvik
• SolarWinds Network Packet Sniffer
• Wireshark
• Paessler PRTG
• ManageEngine NetFlow Analyzer
• Tcpdump
• WinDump
• NetworkMiner

Please refer to the article: Sniffing Tools to learn more about sniffing tools in ethical hacking.

33. What is SQL injection?

SQL injection is a technique used to exploit user data through web page input by injecting SQL commands as statements. Essentially, these instructions can be used by a malicious user to manipulate her web server for your application. SQL injection is a code injection technique that can corrupt your database. Preventing SQL Injection is given below:

• Validation of user input by pre-defining user input length, type, input fields, and authentication.
• Restrict user access and determine how much data outsiders can access from your database. Basically, you shouldn’t give users permission to access everything in your database.
• Do not use system administrator accounts.

To know more about this topic, Please read the article: SQL Injection

34. What is a Distributed Denial of Service attack (DDoS)?

A denial of service (DoS) is a cyber attack against an individual computer or website aimed at denying service to intended users. Its purpose is to interfere with the organization’s network operations by denying her access. Denial of service is usually achieved by flooding the target machine or resource with excessive requests, overloading the system, and preventing some or all legitimate requests from being satisfied.

Please refer to the article: Denial of Service and Prevention to know more.

35. How to avoid ARP poisoning?

Following are the five ways of avoiding ARP Poisoning attacks:

• Static ARP Tables: If you can verify the correct mapping of MAC addresses to IP addresses, half the problem is solved. This is doable but very costly to administer. ARP tables to record all associations and each network change are manually updated in these tables. Currently, it is not practical for an organization to manually update its ARP table on every host.
• Switch Security: Most Ethernet switches have features that help mitigate ARP poisoning attacks. Also known as Dynamic ARP Inspection (DAI), these features help validate ARP messages and drop packets that indicate any kind of malicious activity.
• Physical Security: A very simple way to mitigate ARP poisoning attacks is to control the physical space of your organization. ARP messages are only routed within the local network. Therefore, an attacker may have physical proximity to the victim’s network.
• Network Isolation: A well-segmented network is better than a regular network because ARP messages have a range no wider than the local subnet. That way,  if an attack were to occur, only parts of the network would be affected and other parts would be safe. Attacks on one subnet do not affect devices on other subnets.
• Encryption: Encryption does not help prevent ARP poisoning, but it does help reduce the damage that could be done if an attack were to occur. Credentials are stolen from the network, similar to the MiTM attack.

Please refer to the article: How to Avoid ARP Poisoning? to know more.

36. What is a proxy firewall?

The proxy firewall monitors application-level information using a firewall proxy server. A proxy firewall server creates and runs a process on the firewall that mirrors the services as if they were running on the end host. 
The application layer has several protocols such as HTTP (a protocol for sending and receiving web pages) and SMTP (a protocol for e-mail messages on the Internet). A proxy server like Web Proxy Server is like a process that mirrors the behavior of the HTTP service. Similarly, the FTP proxy server reflects how his FTP service works.

Please refer to the article: What is a Proxy Firewall? to know more.

37.  Explain SSL Encryption.

Secure Socket Layer (SSL) provides security for data transferred between web browsers and servers. SSL encrypts the connection between your web server and your browser, keeping all data sent between them private and immune to attack. Secure Socket Layer Protocols: SSL recording protocol.

Please refer to the article: Secure Socket Layer to know more about it.

38. What do you mean by penetration testing?

Penetration testing is done to find vulnerabilities, malicious content, flaws, and risks. It’s done to make the organization’s security system defend the IT infrastructure. It is an official procedure that can be deemed helpful and not a harmful attempt. It is part of an ethical hacking process that specifically focuses only on penetrating the information system.

Please refer to the article Penetration Testing to learn more about this topic.

39. What are the risks associated with public Wi-Fi?

•  Malware, Viruses, and Worms.
•  Rogue Networks. 
•  Unencrypted Connections
•  Network Snooping. 
•  Log-in Credential Vulnerability. 
•  System Update Alerts.
•  Session Hijacking.

Please refer to the article Risks Associated with Public Wi-Fi to learn more about this topic.

40. Explain the main difference between Diffie-Hellman and RSA.

• Diffie-Hellman (DH) algorithm: It is a key exchange protocol that allows two parties to communicate over a public channel and establish a shared secret without sending it over the Internet. DH allows two people to use their public key to encrypt and decrypt conversations or data using symmetric cryptography.
• RSA: It is a type of asymmetric encryption that uses two different linked keys. RSA encryption allows messages to be encrypted with both public and private keys. The opposite key used to encrypt the message is used to decrypt the message.

41. Give some examples of asymmetric encryption algorithms.

Asymmetric key cryptography is based on public and private key cryptography. It uses two different keys to encrypt and decrypt messages. More secure than symmetric key cryptography, but much slower.

• You need two keys, a public key, and a private key. One for encryption and one for decryption. 
• The ciphertext size is equal to or larger than the original plaintext. 
• Slow encryption process. 
• Used to transfer small amounts of data. 
• Provides confidentiality, authenticity, and non-repudiation.

Please refer to the article Symmetric and Asymmetric Key Encryption to learn more about this topic.

42. Explain social engineering and its attacks.

Social engineering is a  hacking technique based on forging someone’s identity and using socialization skills to obtain details. There are techniques that combine psychological and marketing skills to influence targeted victims and manipulate them into obtaining sensitive information. The types of social engineering attacks are given below:

• Impersonation: This is a smart choice for attackers. This method impersonates organizations, police, banks, and tax authorities. Then they steal money or anything they want from the victim. And the same goes for organizations that obtain information about victims legally through other means. 
• Phishing: Phishing is like impersonating a well-known website such as Facebook and creating a fake girlfriend website to trick users into providing account credentials and personal information. Most phishing attacks are carried out through social media such as Instagram, Facebook, and Twitter.
• Vishing: Technically speaking, this is called “voice phishing”. In this phishing technique, attackers use their voice and speaking skills to trick users into providing personal information. In general, this is most often done by organizations to capture financial and customer data.
• Smithing: Smithing is a method of carrying out attacks, generally through messages. In this method, attackers use their fear and interest in a particular topic to reach out to victims through messages. These topics are linked to further the phishing process and obtaining sensitive information about the target.

Please refer to the article Social Engineering: The Attack on Human Brain and Trust to learn more about this topic.

43. State the difference between a virus and worm.

• Worms: Worms are similar to viruses, but do not modify the program. It replicates more and more to slow down your computer system. The worm can be controlled with a remote control. The main purpose of worms is to eat up system resources. The 2000 WannaCry ransomware worm exploits the resource-sharing protocol Windows Server Message Block (SMBv1).
• Virus: A virus is malicious executable code attached to another executable file that can be harmless or modify or delete data. When a computer program runs with a virus, it performs actions such as B. Delete the file from your computer system. Viruses cannot be controlled remotely. The ILOVEYOU virus spreads through email attachments.

Please refer to the article Difference between Worms and Virus to know more about this topic.

44. Explain the concept of session hijacking.

Session hijacking is a security attack on user sessions over a protected network. The most common method of session hijacking is called IP spoofing, where an attacker uses source-routed IP packets to inject commands into the active communication between two nodes on a network, allowing an authenticated impersonation of one of the users. This type of attack is possible because authentication usually only happens at the beginning of a TCP session. The types of session hijacking are given below:

• Packet Sniffing
• CSRF (Cross-site Request Forgery)
• Cross-site Scripting
• IP spoofing

Please refer to the article Session Hijacking to learn more about this topic.

45. Explain the honeypot and its types.

A honeypot is a networked system that acts as a trap for cyber attackers to detect and investigate hacker tactics and types of attacks. Acting as a potential target on the Internet, it notifies defenders of unauthorized access to information systems. Honeypots are classified based on their deployment and intruder involvement. Based on usage, honeypots are classified as follows: 

• Research honeypots: Used by researchers to analyze hacking attacks and find different ways to prevent them. 
• Production Honeypots: Production honeypots are deployed with servers on the production network. These honeypots act as a front-end trap for attackers composed of false information, giving administrators time to fix all vulnerabilities in real systems.

Please refer to the article What is Honeypot? to know more about this topic.

46. What do you mean by a Null Session?

Null session attacks have existed since Windows 2000 was widely used. However, system administrators do not consider this type of attack when implementing network security measures. This can have unimaginable consequences, as this type of attack allows hackers to obtain all the information they need to access your system remotely. This type of attack is more difficult to execute if the customer is using a newer version of the operating system, but Windows XP and Windows Server 2003 are still the most common. 

Please refer to the article Null Session to learn more about this topic.

47. What is IP blocklisting?

IP blacklisting is a method used to block unauthorized or malicious IP addresses from accessing your network. A blacklist is a list of ranges or individual IP addresses to block.

Please refer to the article What is IP blocklisting? to know more about this topic.

48. What are Polymorphic viruses?

“Poly” refers to many and “morphic” refers to the shape. Thus, polymorphic viruses, as the name suggests, are complex computer viruses that change shape as they spread in order to avoid detection by antivirus programs. This is a self-encrypting virus that combines a mutation engine with a self-propagating code. A polymorphic virus consists of:

• Encrypted virus body mutation engine that generates random decryption routines.
• A polymorphic virus has its mutation engine and virus body encrypted. When an infected program is run, a virus decryption routine takes control of the computer and decrypts the virus body and mutation engine.
• Control is then passed to the virus to detect new programs to infect. Since the body of the virus is encrypted and the decryption routine varies from infection to infection, virus scanners cannot look for a fixed signature or fixed decryption routine, making detection more difficult.

Please refer to the article Polymorphic Viruses to learn more about this topic.

49. What is a Botnet?

A botnet (short for “robot network”) is a network of malware-infected computers under the control of a single attacker known as a “bot herder”. An individual machine under the control of a bot herder is called a bot.

Please refer to the article Botnet in Computer Networks to learn more about this topic.

50. What is an Eavesdropping Attack?

Eavesdropping occurs when a hacker intercepts, deletes or modifies data sent between two devices. Eavesdropping, also known as sniffing or snooping, relies on unsecured network communications to access data sent between devices.

Please refer to the article Eavesdropping Attack to learn more about this topic.

51. What is the man-in-the-middle attack?

This is a type of cyber attack in which the attacker stays between the two to carry out their mission. The type of function it can perform is to modify the communication between two parties so that both parties feel like they are communicating over a secure network.

Please refer to the article: Man In the Middle Attack to learn more about this topic.

52. What is a traceroute? Why is it used?

Traceroute is a widely used command line tool available on almost all operating systems. A complete route to the destination address is displayed. It also shows the time  (or delay) between intermediate routers.

Uses of traceroute: 

• It enables us to locate where the data was unable to be sent along
• Traceroute helps provide a map of data on the internet from  source to  destination
• It works by sending ICMP (Internet Control Message Protocol) packets.
• You can do a visual traceroute to get a visual representation of each hop.

Please refer to the article: Traceroute in Network Layer to know more about it.

53. What is the difference between HIDS and NIDS?

• HIDS: This intrusion detection system sees the host itself as a whole world. It can be a computer (PC) or a server that can act as a standalone system and analyze and monitor its own internals. It works by looking at the files/data coming in and out of the host you’re working on. It works by taking existing file system snapshots from a previously taken file system and comparing them to each other. If they are the same, it means the host is safe and not under attack, but a change could indicate a potential attack.
• NIDS: This system is responsible for installation points across the network and can operate in mixed and hybrid environments. Alerts are triggered when something malicious or anomalous is detected in your network, cloud, or other mixed environments.

Please refer to the article:  Difference between HIDs and NIDs to know more about it.

54. What is the difference between VA (Vulnerability Assessment) and PT (Penetration Testing)?

• Penetration testing: This is performed to find vulnerabilities, malicious content, bugs, and risks. Used to set up an organization’s security system to protect its IT infrastructure. Penetration testing is also known as penetration testing. This is an official procedure that can be considered helpful, not a harmful attempt. This is part of an ethical hacking process that focuses solely on breaking into information systems.
• Vulnerability assessment: It is the technique of finding and measuring (scanning) security vulnerabilities in a particular environment. This is a location-comprehensive evaluation (result analysis) of information security. It is used to identify potential vulnerabilities and provide appropriate mitigations to eliminate them or reduce them below the risk level.

Please refer to the article: Differences between Penetration Testing and Vulnerability Assessments to know more.

55. What is RSA?

The RSA algorithm is an asymmetric encryption algorithm. Asymmetric means that it actually works with two different keys. H. Public and Private Keys. As the name suggests, the public key is shared with everyone and the private key remains secret.

Please refer to the article: RSA Algorithm in Cryptography to know more.

56. What is the Blowfish algorithm?

Blowfish is an encryption technique developed by Bruce Schneier in 1993 as an alternative to the DES encryption technique. It is considerably faster than DES and provides excellent encryption speed even though no effective cryptanalysis techniques have been discovered so far. It was one of the first secure block ciphers to be patent-free and therefore freely available to everyone. 

• Block size: 64 bits 
• keys:  variable size from 32-bit to 448-bit 
• Number of subkeys: 18 [P array] 
• Number of rounds: 16 
• Number of replacement boxes: 4 [each with 512 entries of 32 bits]

Please refer to the article: Blowfish Algorithm to know more.

57. What is the difference between a vulnerability and an exploit?

• Vulnerability: A vulnerability is an error in the design or implementation of a system that can be exploited to cause unexpected or undesirable behaviour. There are many ways a computer can become vulnerable to security threats. A common vulnerability is for attackers to exploit system security vulnerabilities to gain access to systems without proper authentication.
• Exploit: Exploits are tools that can be used to exploit vulnerabilities. They are created using vulnerabilities. Exploits are often patched by software vendors as soon as they are released. They take the form of software or code that helps control computers and steal network data.

Please refer to the article: Difference Between Vulnerability and Exploit to know more about it.

58.  What do you understand by Risk, Vulnerability and threat in a network?

• Cyber threats are malicious acts aimed at stealing or corrupting data or destroying digital networks and systems. A threat can also be defined as the possibility of a successful cyberattack to gain unethical access to sensitive data on a system.
• Vulnerabilities in cybersecurity are deficiencies in system designs, security procedures, internal controls, etc. that can be exploited by cybercriminals. In very rare cases, cyber vulnerabilities are the result of cyberattacks rather than network misconfigurations.
• Cyber ​​risk is the potential result of loss or damage to assets or data caused by cyber threats. You can’t eliminate risk completely, but you can manage it to a level that meets your organization’s risk tolerance. Therefore, our goal is not to build a system without risk but to keep the risk as low as possible.

Please refer to the article: Difference Between Threat, Vulnerability and Risk in Computer Networks to know more.

59. Explain Phishing and how to prevent it.

Phishing is a type of cyber attack. The name phishing comes from the word ‘phish’, which means fish. Placing bait to catch fish is a common phenomenon. Phishing works similarly. Tricking users or victims into clicking on malicious websites is an unethical practice.

Here’s how to protect your users from phishing attacks. 

• Download software only from authorized sources
•  Do not share personal information on unknown links. 
• Always check website URLs to prevent such attacks.
• If you receive an email from a known source, but the email seems suspicious,  contact the sender with a new email instead of using the reply option.
• Avoid posting personal information such as phone numbers, addresses, etc. on social media.
• Monitor compromised websites with malicious content using phishing detection tools. Try to avoid free Wi-Fi.

60. What do you mean by Forward Secrecy and how does it work?

Forward secrecy is a feature of some key agreement protocols that guarantees that the session keys will remain secure even if the server’s private key is compromised. Perfect forward secrecy, also known as PFS, is the term used to describe this. The “Diffie-Hellman key exchange” algorithm is employed to achieve this.