Malicious software

The aim of this blog is to discuss the term malware and introduce commonly known malware types. Malware is a type of software that is malicious to your system and has the purpose of obtaining, deleting, or modifying the files or information to use them for unwanted purposes. Viruses, worms, spyware, trojans, adware, backdoors, botnets are the most common types of malware.

Viruses are a type of computer program which attaches themselves to other files or programs by inserting their own code into them when executed. It replicates itself so quickly and it spreads as far as it can and does its malicious work.

Worms are the other malware type that is quite similar to viruses. Differently, worms don’t need to attach somewhere to live. Worms can live on their own and can spread eg. through networks or as an email attachment. ILOVEYOU worm is one of famous computer worm which was created in 2000 and affected millions of Windows computers. The outbreak was later estimated to have caused US$5.5–8.7 billion in damages worldwide and estimated to cost US$10–15 billion to remove the worm. Within ten days, over fifty million infections had been reported, and it is estimated that 10% of Internet-connected computers in the world had been affected. It was spread by an e-mail with the subject line of I Love You and it contains a text file attachment that is actually a worm. Once the file is opened, it would execute many attacks like copying itself to several files and folders, launching other malicious software, replacing files, and then hiding itself after it was done. The worm spread by stealing e-mail addresses that were in the victim’s computer and chat clients. It then proceeded to send that email out to everyone in the address book.

Adware is a very common malware which we encounter in our daily lives. Its aim is to display advertisements and collect data for especially marketing purposes. Sometimes we let them by clicking ”agree” or ”consent” and agree the terms of services of the website.

The other common malware is trojan. Trojans are malicious code or software which are seen as legitimate but actually do something else malicious like taking the control of your computer. It has to be accepted by the computer user so it has to disguise itself as another program. The name comes from the trojan horse which was sent to enemies by the Greeks in history. It does actually the same thing.

Spyware is a kind of malware that’s meant to spy on people by monitoring their computer screens, keypresses, webcams, and then reporting or streaming all of this information to another party. It invades the device, steals sensitive information or internet usage data, and relays it to advertisers, data firms, or external users. Keylogger is a common type of spyware. It captures all the messages or confidential data like credentials or passwords, written by the user.

One of most the effective and influential malware types is ransomware. It is meant to take the sensitive data, system, etc. as hostages until paying for them. It causes millions of dollars of loss for companies. Ransomware grows 400% in 2021 according to experts. Furthermore, it affects daily life and crucial services like healthcare services. For example, the ransomware attack shut down the systems for the National Health Services in England in 2017, causing a health-related crisis. The WannaCry is another ransomware attack that devastated systems around the world.

Commonly the purpose of malware is to steal, use or affect sensitive data, but sometimes they steal the resources like CPU. The name of the compromised machine is Bots. Bots are usually used to perform a task controlled by the attacker. The network which consists of multiple bots is called Botnets. Bitcoin mining is a good example of the use of internet-connected botnets.

Backdoors are other types of attacking types to the systems by attackers. Firstly attackers gain access to the system by using appropriate ways and then install a backdoor to maintain that access and control the system. It can be said that it is a kind of bypassing the usual authentication or encryption.

Malwares are quite common in today’s connected world. They cause various types of unwanted stuff if we do not aware of them. We will discuss to do’s or not to do’s in the next article.


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