O que é: Malware

What is malware

Malware (comes from the combination of words malicious and software) is a common name for several types of software, designed to gain unauthorized access to computing devices (computers, smartphones, etc.) or networks and/or intentionally harm users of these devices. Thus, software is defined as malware, depending on the purpose of its use, rather than on the particular methodology or technology this software is based on.

Purposes of use

The first malware programs were created as an experiment or for fun. Today, malicious software is most often used to steal information - financial, personal, or business-related. Malicious software can be used both for attacks on organizations (penetration into a local network) and even on a country, as well as for stealing particular information about an individual (theft of bank data, access details to various services, etc.). Most of currently existing viruses and worms are designed to gain control over the attacked device (computer, smartphone, etc.). After this, the monitored device can be used for sending spam, store illegal information (e.g. child pornography) or for performing attacks of other types.

Classification of Malware

Some malware products can belong to several types at the same time; such programs often have traits of Trojans and worms, and sometimes viruses as well. Typically, a malicious program is delivered to the end user as a Trojan horse, but after launch it fixes itself on the user's device and infects executable files of other programs, i.e. acts like a virus; it also can attack other devices over the network, i.e. act like a worm.

Viruses

A computer virus is a program hidden in other software, usually useful or harmless. Viruses are able to create copies of themselves and insert them into executable files of other programs. A virus usually performs some malicious action - for example, data theft or destruction.

Worms

A computer (network) worm is software that copies itself to other computers through a computer network in order to distribute itself. Usually, gaps in operating systems or network settings are used for this.

Spyware

Spyware is software whose purpose is to steal private information from a computer system for a third party. Spyware collects the information and sends it to an attacker.

Trojan horses

A Trojan horse (or simply 'a Trojan') is a malicious program that disguises itself as a regular useful program or an app to convince the victim to install it. A Trojan horse usually carries a hidden destructive function activated when the Trojan-laden application starts. The term is derived from an ancient Greek story about a Trojan horse used to covertly invade the city of Troy. Unlike computer viruses and worms, Trojan horses usually do not try to embed themselves in other files or otherwise spread themselves.

Logic bombs

A logical bomb is a malicious program that uses a trigger for activating malicious code. A logic bomb does not work until this trigger event occurs. Once launched, a logic bomb injects malicious code that harms the computer. Cybersecurity experts recently discovered logic bombs that attack and destroy equipment components on workstations or servers, including cooling fans, hard drives, and power supplies. The logic bomb overloads these devices until they overheat or fail.

Ransomware

A screen blocker is a pseudo-police program that locks the screen on the device and informs the user that he or she is ostensibly accused of collecting illegal content, trying to scare the victim and make him or her pay the "fine".

Rootkits

A rootkit is a malicious program that hides its presence with the help of a low-level modification of the infected system. Rootkits can prevent the appearance of their executable process in the list of system processes or block reading of their files.

Backdoors

A backdoor is a malicious program that provides access to the infected device by means of bypassing normal authentication procedures, usually through a network connection. After a system (computer or subnet) is hacked, a backdoor can be installed to provide access to the hacked system in the future, invisibly to its user.

Adware

Adware is a type of malware that redirects your browser to an advertising web page without your consent. Often these pages try to download other malware. As cyber security experts say, adware is often found in so-called free programs, such as games or browser extensions.

Cryptojacking

Cryptojacking is malware that uses power of your device (e.g. computer) to mine cryptocurrencies without your knowledge. Such mining software may run in the background on your operating system or even like JavaScript in a browser window.

Malvertising (Malicious Advertising)

Malicious advertising is using legitimate advertisements or ad networks to deliver malware. For example, a cybercriminal may pay for placing an advertisement on some website. When a user clicks on this ad, the code in the ad either redirects the user to a malicious website or installs malware on the victim's computer. In some cases, malware embedded in such ads can run automatically without any user’s action - this method is called "boot from disk".

Methods of Infection

Security Gaps in Software

Malicious software may use security flaws (vulnerabilities) in the operating system, individual applications, or application extensions (plug-ins). A common method of infection is to exploit the buffer overflow vulnerability.

Overly privileged users and overly privileged code

In computer systems, different users and programs have different privileges as to how they can influence the system. In poorly designed systems, users and programs can be given too high privileges without explicit need for it, and malicious software can take advantage of this.

Insecure system settings or user errors

Insecure settings include, for example, ability to autoload from removable media (USB, CD, DVD, etc.). User errors are actions of the device user, which lead to infection. Most often, these actions include launching programs of dubious or obviously dangerous origin (cracks and keygens for paid software, opening email attachments, etc.) without checking them first.