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Fileless Malware
Fileless malware is a type of malicious activity that uses native, legitimate tools built into a system to
execute a cyber attack. Unlike traditional malware, fileless malware does not require an attacker to
install any code on a target’s system, making it hard to detect.

Ransomware
Ransomware is a type of malware that prevents or limits users
from accessing their system, either by locking the system’s screen
or by locking the users’ files until a ransom is paid. More modern
ransomware families, collectively categorised as cryptoransomware,
encrypt certain file types on infected systems and force users to
pay the ransom through certain online payment methods to get a
decryption key. Ransomware can be downloaded onto systems when unwitting users visit malicious or
compromised websites. It can also arrive as a payload that is either dropped or downloaded by other
malware. Some ransomware are delivered as attachments from spammed email, downloaded from
malicious pages through malvertisements, or dropped by exploit kits onto vulnerable systems.
Once executed in the system, ransomware can either lock the computer screen or, in the case of
cryptoransomware, encrypt predetermined files. In the first scenario, a full-screen image or notification
is displayed on an infected system’s screen, which prevents a victim from using their system. This
notification also details instructions on how a user can pay the ransom. In the second scenario,
ransomware prevents access to potentially critical or valuable files like documents and spreadsheets.

Malvertising
Malvertising (a portmanteau of ‘malicious software (malware) advertising’) is the
use of online advertising to spread malware. It typically involves injecting malicious
or malware-laden advertisements into legitimate online advertising networks
and webpages. Because advertising content can be inserted into high-profile and
reputable websites, malvertising provides malefactors with an opportunity to
push their attacks on web users who might not otherwise see the ads, due to firewalls, more safety
precautions, or the like. Malvertising is attractive to attackers because it can be easily spread across a
large number of legitimate websites without directly compromising those websites.

Botnet
A botnet is a logical collection of Internet-connected devices, such as
computers, smartphones, or Internet of Things (IoT) devices, whose
security have been breached and control ceded to a third party. Each
compromised device, known as a ‘bot’, is created when a device
is penetrated by software from a malware (malicious software)
distribution. The controller of a botnet is able to direct the activities of
these compromised computers through communication channels formed by standards-based network
protocols, such as IRC and Hypertext Transfer Protocol (HTTP).

Mobile Malware
Mobile malware is malicious software specifically designed to target mobile
devices, such as smartphones and tablets, with the goal of gaining access to
private data.

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