Cyber Security Threats (Cambridge (CIE) O Level Computer Science): Revision Note

Forms of cyber security threat

• Computers face a variety of forms of attack and they can cause a large number of issues for a network and computers

• The main threats posed are:

  • Brute-force attacks

  • Data interception & theft

  • DDos attack

  • Hacking

  • Malware

  • Pharming

  • Phishing

  • Social engineering

Brute Force Attack

What is a brute-force attack?

• A brute force attack works by an attacker repeatedly trying multiple combinations of a user's password to try and gain unauthorised access to their accounts or devices

• An example of this attack would be an attacker finding out the length of a PIN code, for example, 4-digits

• They would then try each possible combination until the pin was cracked, for example

  • 0000

  • 0001

  • 0002

• A second form of this attack, commonly used for passwords is a dictionary attack

• This method tries popular words or phrases for passwords to guess the password as quickly as possible

• Popular words and phrases such as 'password', '1234' and 'qwerty' will be checked extremely quickly.

Data interception

What is data interception & theft?

• Data interception and theft is when thieves or hackers can compromise usernames and passwords as well as other sensitive data

• This is done by using devices such as a packet sniffer

• A packet sniffer will be able to collect the data that is being transferred on a network

• A thief can use this data to gain unauthorised access to websites, companies and more 

DDoS Attack

What is a DDoS attack?

• A Distributed Denial of Service Attack (DDoS attack) is a large scale, coordinated attack designed to slow down a server to the point of it becoming unusable

• A server is continually flooded with requests from multiple distributed devices preventing genuine users from accessing or using a service

• A DDoS attack uses computers as 'bots', the bots act as automated tools under the attackers control, making it difficult to trace back to the original source

• A DDoS attack can result in companies losing money and not being able to carry out their daily duties

• A DDoS attack can cause damage to a company's reputation

Hacking

What is hacking?

• Hacking is the process of identifying and exploiting weaknesses in a computer system or network to gain unauthorised access

• Access can be for various malicious purposes, such as stealing data, installing malware, or disrupting operations

• Hackers seek out opportunities that make this possible, this includes:

  • Unpatched software

  • Out-of-date anti-malware

Malware

What is malware?

• Malware (malicious software) is the term used for any software that has been created with malicious intent to cause harm to a computer system

• Examples of issues caused by malware include

  • Files being deleted, corrupted or encrypted

  • Internet connection becoming slow or unusable

  • Computer crashing or shutting down 

• There are various types of malware and each has slightly different issues which they cause

Pharming

What is pharming?

• Pharming is typing a website address into a browser and it being redirected to a 'fake' website in order to trick a user into typing in sensitive information such as passwords

• An attacker attempts to alter DNS settings, the directory of websites and their matching IP addresses that is used to access websites on the internet or change a users browser settings

• A user clicks a link which downloads malware

• The user types in a web address which is then redirected to the fake website

How can you protect against it?

• To protect against the threat of pharming:

  • Keep anti-malware software up to date

  • Check URLs regularly

  • Make sure the padlock icon is visible

Phishing

What is phishing?

• Phishing is the process of sending fraudulent emails/SMS to a large number of people, claiming to be from a reputable company or trusted source

• Phishing is an attempt to try and gain access to your details, often by coaxing the user to click on a login button/link

Social Engineering

What is social engineering?

• Social engineering is exploiting weaknesses in a computer system by targeting the people that use or have access to them

• There are many forms of social engineering, some examples include

  • Fraudulent phone calls: pretending to be someone else to gain access to their account or their details

  • Pretexting: A scammer will send a fake text message, pretending to be from the government or human resources of a company, this scam is used to trick an individual into giving out confidential data

• People are seen as the weak point in a system because human errors can lead to significant issues, some of which include:

  • Not locking doors to computer/server rooms

  • Not logging their device when they're not using it

  • Sharing passwords

  • Not encrypting data

  • Not keeping operating systems or anti-malware software up to date