Book Image

Practical Network Scanning

By : Ajay Singh Chauhan
Book Image

Practical Network Scanning

By: Ajay Singh Chauhan

Overview of this book

Network scanning is the process of assessing a network to identify an active host network; same methods can be used by an attacker or network administrator for security assessment. This procedure plays a vital role in risk assessment programs or while preparing a security plan for your organization. Practical Network Scanning starts with the concept of network scanning and how organizations can benefit from it. Then, going forward, we delve into the different scanning steps, such as service detection, firewall detection, TCP/IP port detection, and OS detection. We also implement these concepts using a few of the most prominent tools on the market, such as Nessus and Nmap. In the concluding chapters, we prepare a complete vulnerability assessment plan for your organization. By the end of this book, you will have hands-on experience in performing network scanning using different tools and in choosing the best tools for your system.
Table of Contents (19 chapters)
Title Page
Packt Upsell
Contributors
Preface
Index

Why security?


As the internet grows and technology evolves for modern computer networks, network security has become one of the most crucial factors for everyone. This includes everyone from end users and small and medium-sized businesses (SMBs) to cloud service providers.

Due to a growing volume of network attacks, network security should be a priority when designing network architecture. To understand the importance of this, imagine what could happen if there was a network integrity breach at a bank, stock exchange, or other financial database.

The importance of network security is not just limited to the IT industry. It is also important within industries such as health care. Health records contain some of the most valuable information available, including Social Security numbers, home addresses, and patient health histories. If this data is accessed by unauthorized persons, it can be stolen or sold to the black market.

Security awareness is important for everybody and not just the IT department. If you work with internet enabled devices, it's your responsibility too. However, you can only control information security once you know how to secure it.

No one can get into your system until something is compromised. Similarly, if your door is locked from the outside, nobody can enter your house unless they gain access to a duplicate key or have a similar key built by getting physical access to the lock. A few examples of how a system might be compromised are as follows:

  • A targeted email could be sent to random users with an attachment (Drive by Download). If a user opened that attachment, their system would be compromised.
  • An email is received which poses as a domain such as banking and asks you to change your password through a provided link. Once you do this, your username and password can be stolen.
  • If a small typo is made when typing a website address into a browser, a similar page may open (Phishing) which is not genuine, and your credentials can be stolen.
  • Features provided by websites for resetting forgotten passwords can also be very risky. Let's say somebody knows my email ID and attempts to access my account by selecting a forgotten password option. If the security question asks for my date of birth, this can easily be found on my resume.
  • A password for an Excel file can easily be broken by a brute-force attack.
  • The most widespread types of ransomware encrypt all or some of the data on your PC, and then ask for a large payment (the ransom) in order to restore access to your data.
  • During DNS hijacking, an online attacker will override your computer's TCP/IP settings so that the DNS translation gets altered. For example, typing in abc.com will translate it into this IP: 140.166.226.26. However, a DNS hijacker will alter the translation so that abc.com will now send you the IP address of a different website.
  • Denial of Service network attacks disrupt the normal volume of traffic sent to targeted services with excessive amounts of traffic. This can be damaging in various ways. One example could be if a company has a Friday sale, and a competitor launches an attack on them in order to shut their services down and consequently increase their own sales.

According to research by British insurance company Lloyd's, the damage from hacks cost businesses $400 billion a year.

To further explore the cost of cybercrimes, visit the following webpage:  https://www.forbes.com/sites/stevemorgan/2016/01/17/cyber-crime-costs-projected-to-reach-2-trillion-by-2019/#612db25c3a91.

The market research firm Gartner estimates that global spending on cybersecurity is somewhere around $96 billion in 2018. By 2020, companies around the world are expected to spend around $170 billion—a growth rate of nearly ten percent in the next five years.