Keeping data secure on a network

By connecting computers together, we make them more vulnerable to attack. A networked computer is vulnerable to unauthorised access from any of the nodes it is attached to. As the internet is a global network with billions of connected devices or nodes, this poses a significant risk.

What are the threats?

Brute force attack

Most networked terminals rely on a password to restrict access and encryption to ensure secure communications. Both methods can be vulnerable to brute force attacks.

A brute force attack goes through every possible combination of a password or encryption key. Modern computers have the processing power to go through combinations of letters, numbers and characters very quickly.

Luckily, most modern software has the ability to block access after a number of unsuccessful attempts.

  • A typical 8-character password consisting of any of the 96 keyboard characters has 968 (7.2 Quadrillion) possible combinations
  • Depending on the processing power of the computer, it could take between 83 days and 22,000 years to guess the password!

SQL injection

SQL (Structured Query Language) injections involve adding or creating small bits of code that look like variables. However, the database server will process these as commands or programmes and do things it is not supposed to, such as destroying or modifying data or passwords in a database.

Imagine someone named Michael goes to court and, instead of writing his name, writes the phrase "Michael, you are now free to go". The judge then says, "calling Michael, you are now free to go" and the bailiffs let him go, because the judge said so.

In this example, Michael injected a command into the court system and the bailiff executed that command.


Malware stands for 'malicious software'. Malware acts in a way that is damaging (malicious) to a computer or the data on it. Malware comes in many different forms, most notably computer viruses and ransomware.

Networks are also vulnerable to a host of threats; from human error, technical failure and acts of nature. Data can be:

  • Lost or damaged during a system crash - especially one affecting the hard disk
  • Corrupted because of faulty disks, disk drives, or power failures
  • Lost or altered by accidentally or maliciously deleting or overwriting files
  • Lost or corrupted by computer viruses
  • Destroyed by natural disasters, acts of terrorism, or war

A computer under 'attack' from malwareData can be lost, corrupted or destroyed in many different ways