Common types of Malware

Ransomware
This is becoming more and more popular these days. Infection usually spread via email attachments or malicious urls which triggers a download. Commonly, ransomware encrypts data files on a computer and only way to decrypt your file is to pay the ransom to the attacker through crypto currency. That too within a very short period of time. If not paid, your files are deleted.

Rootkits
Rootkits are malware that hides inside the computer's operating system. It remains concealed and avoids easy detection. You will not even know when the harm was done.

Botnets
Botnet is a collection of software robots (generally known as bots) that together creates and army of infected computers (generally known as zombies) that are remotely controlled by the attacker. Botnet is typically used to execute denial-of-service attack (Dos attack) or distributed denial-of-service (DDoS attack). You may even not know when your computer was a part of bots.


Viruses
These are most common types of malware and does many damaging things to your computer. Delivery is mostly through email attachments or download triggered by click on malicious link. It propagates by making copies of themselves. When infected program is executed, the virus attempts to replicate itself by copying itself into other programs while doing the intended jobs.

Worms
Unlike virus, worms goes to work on its own without attaching itself to a program or files. Worms live in a computer's memory and can propagate by sending themselves to other computers in a network or across the internet by itself. They can quickly infect large numbers of computers and may cause a firm's network to be overwhelmed with traffic and slow down or stop working all together.

Trojans
If you've watch the movie "Troy" you already know what trojan is. It is a malicious program disguised as a legitimate-looking software. You fall a victim to this program when you download games, screensavers, rogue security software etc. After installation Trojan will auto run in background. These are mostly used to create a backdoor to a computer to exfiltrate sensitive information.

Common Online Threats

Common Types of Malware

Malware - Detection and Prevention

Cyber Security: Why Malware?

What is malware for?
There are many reasons why malware is created including intellectual curiosity, financial gain or corporate espionage.

Many programmers thrive on the challenge of seeing what is possible, and set out to create a malware program even if they do not intend to do harm. Perhaps the most famous of these experiments was the 1988 Morris Worm – the first worm to spread over the internet. The supposed intent of this worm was to gauge the number of machines connected to the network. However, the result was to slow down the operation of infected machines to the point of being unusable.

Worms continue to represent a major threat, as shown by the case of the Conficker worm of 2008.

 

Case study: Conficker
In 2008, Microsoft Windows computers began being infected by an advanced worm called Conficker, which spread when users shared files, either over networks or via USB flash memory drives. The malware disabled important security features, such as anti-virus software and automated update systems and blocked users from downloading fixes. At the same time, Conficker would exploit a weakness in Microsoft’s server software to infect computers on the same network.

Conficker became the fastest-spreading malware known then, eventually being found in almost every country. Conficker outbreaks were reported from (among others) the armed forces of the UK, France and Germany, as well as the British House of Commons and UK police forces. In the US, Conficker’s impact was sufficiently serious that the Department of Homeland Security set up a Conficker Working Group of security experts tasked with creating strategies that could be used against similar outbreaks in the future.

Conficker’s authors were clearly not amateurs. They released new variants of Conficker on a regular basis to overcome weaknesses in the original malware and took steps, (including using digital signatures), to ensure that no one else could hijack their program.

Although Conficker caused a great deal of nuisance, it did not appear to do any actual harm to data, however, the program could have delivered other malware that would have attacked users. In many ways, Conficker was a harbinger of the advanced criminal malware – such as Cryptolocker – that is a major threat to today’s users.

https://www.futurelearn.com/courses/introduction-to-cyber-security/8/steps/83065

CyberSecurity: Malware - Virus, Worms and Trojans

The two biggest threats to consumers online are malware and phishing.

Malware is the collective name for software that has been designed to disrupt or damage data, software or hardware. There are several types of malware, such as viruses, worms and Trojans.

However, as malware has evolved, from its beginnings as demonstrations of prowess by individual programmers to sophisticated technologies developed by organised crime, the boundaries between the different categories are beginning to blur. 

Viruses
The best-known type of malware is probably the virus, although many pieces of malware are called viruses they are nothing of the sort.

A virus is a piece of software that has been written to insert copies of itself into applications and data and onto crucial parts of a computer’s hard disk. Viruses are said to be self-replicating programs and date back as far as the early 1970s, but they only became well known with the advent of microcomputers and later, the internet.

Viruses attach themselves to specific applications on a computer and are activated when the program is first run. At that point, the virus may make a copy of itself on the hard disk and continue to run, or it may only run each time the application is used. Early viruses, relying on floppy disks for transmission, spread quickly as infected data disks were shared around an office, or pirated software was passed around a playground. Nowadays, viruses rely on devices such as flash memory cards or are transmitted through internet connections.

Although some viruses are not intended to cause harm, the majority of these programs are designed to harm users, by corrupting their data or attacking the operating system itself or providing an exploitable ‘backdoor’, giving attackers access to the computer. Even where no harm is intended, viruses consume memory, disk space and processing power.

Worms
Another type of self-replicating malware is the worm; like a virus it is designed to make copies of itself; but unlike a virus, a worm is a standalone application.

Worms spread through network connections, accessing uninfected machines and then hijacking their resources to transmit yet more copies across the network.

There are four stages in a worm attack:

The first stage is when the worm probes other machines looking for a vulnerability that can be exploited to copy itself to.
The next stage is to penetrate the vulnerable machine by performing the operations for exploiting the vulnerability. For example, the worm might detect an open network connection, through which it can get the remote machine to execute arbitrary instructions.
In the third stage, the worm will download itself to the remote machine, and store itself there. This is often called the ‘persist’ stage.
In the next stage, the worm will propagate itself by picking new machines to attempt to probe.
Worms were invented as a curiosity and have even been suggested as ways of testing networks or distributing software patches across a network; however their drawbacks far outweigh their benefits. Even the most ‘benign’ worm consumes resources and can affect the performance of a computer system.

Trojans
The final major type of malware is the Trojan (or Trojan horse); named after the wooden horse that supposedly smuggled Greek soldiers into the ancient city of Troy.
A Trojan disguises itself as an entirely legitimate program (such as a screensaver), but behind the scenes it is causing damage – perhaps allowing someone else to gain control of the computer, copying personal information, deleting information, monitoring keystrokes, or using email software to pass itself on to other computers. Unlike viruses and worms, Trojans are not self-replicating, they rely on their apparent usefulness to spread between computers.

Some Trojans work in isolation. Some, however, rely on networks, either to transmit stolen information – such as passwords, bank account details or credit card numbers – or to act as back doors to compromised computers. They allow attackers to bypass the operating system’s security features and gain access to data or even control the machine over a network.

For More:
https://www.futurelearn.com/courses/introduction-to-cyber-security/8/steps/83062

Malware - INTRODUCTION TO CYBER SECURITY THE OPEN UNIVERSITY

Malware
Finally, there are a number of terms associated with software that attempts to harm computers in different ways. Collectively these are known as ‘malware’ (a contraction of malicious software).

Depending on what the malware does, different terms are used to in relation to malware. For example:

• ransomware is malware that demands payment in order to refrain from doing some harmful action or to undo the effects of the harmful action
• spyware records the activities of the user, such as the passwords they type into the computer, and transmits this information to the person who wrote the malware
• botnets are created using malware that allows an attacker to control a group of computers and use them to gather personal information or launch attacks against others, such as for sending spam emails or flooding a website with so many requests for content that the server cannot cope, called a denial-of-service attack.

Threatsaurus

There are lots of technical terms relating to cyber security and it can be difficult to keep track of what’s what.

Sophos is one of the major players in the anti-malware business. They publish a Threatsaurus to help you remember and define the terms relating to malware. The Threatsauras is a plain-English guide, to help IT managers and end users understand the threats posed by malicious software. The Threatsaurus, includes:

• an A–Z glossary on computer and data security threats
• practical tips to stay safe from email scams, identity theft, malware and other threats
• a guide to Sophos’s security software and hardware.
• Download the Sophos Threatsaurus PDF here or from the Sophos website.

Malware - INTRODUCTION TO CYBER SECURITY THE OPEN UNIVERSITY

Malware
Finally, there are a number of terms associated with software that attempts to harm computers in different ways. Collectively these are known as ‘malware’ (a contraction of malicious software).

Depending on what the malware does, different terms are used to in relation to malware. For example:

• ransomware is malware that demands payment in order to refrain from doing some harmful action or to undo the effects of the harmful action
• spyware records the activities of the user, such as the passwords they type into the computer, and transmits this information to the person who wrote the malware
• botnets are created using malware that allows an attacker to control a group of computers and use them to gather personal information or launch attacks against others, such as for sending spam emails or flooding a website with so many requests for content that the server cannot cope, called a denial-of-service attack.

Threatsaurus

There are lots of technical terms relating to cyber security and it can be difficult to keep track of what’s what.

Sophos is one of the major players in the anti-malware business. They publish a Threatsaurus to help you remember and define the terms relating to malware. The Threatsauras is a plain-English guide, to help IT managers and end users understand the threats posed by malicious software. The Threatsaurus, includes:

• an A–Z glossary on computer and data security threats
• practical tips to stay safe from email scams, identity theft, malware and other threats
• a guide to Sophos’s security software and hardware.
• Download the Sophos Threatsaurus PDF here or from the Sophos website.

Malware - INTRODUCTION TO CYBER SECURITY THE OPEN UNIVERSITY

Malware
Finally, there are a number of terms associated with software that attempts to harm computers in different ways. Collectively these are known as ‘malware’ (a contraction of malicious software).

Depending on what the malware does, different terms are used to in relation to malware. For example:

• ransomware is malware that demands payment in order to refrain from doing some harmful action or to undo the effects of the harmful action
• spyware records the activities of the user, such as the passwords they type into the computer, and transmits this information to the person who wrote the malware
• botnets are created using malware that allows an attacker to control a group of computers and use them to gather personal information or launch attacks against others, such as for sending spam emails or flooding a website with so many requests for content that the server cannot cope, called a denial-of-service attack.

 

Threatsaurus

There are lots of technical terms relating to cyber security and it can be difficult to keep track of what’s what.

Sophos is one of the major players in the anti-malware business. They publish a Threatsaurus to help you remember and define the terms relating to malware. The Threatsauras is a plain-English guide, to help IT managers and end users understand the threats posed by malicious software. The Threatsaurus, includes:

• an A–Z glossary on computer and data security threats
• practical tips to stay safe from email scams, identity theft, malware and other threats
• a guide to Sophos’s security software and hardware.
• Download the Sophos Threatsaurus PDF here or from the Sophos website.