computer viruses they are as old as the computers they infect. Already in the middle of the last century they were written about and, of course, they have not abandoned us. On the contrary, the more we use technology, the more elaborate they become, as well as negative and destructive.
These are nothing more than harmful software that is introduced into computer systems with criminal intentions or, at least, annoying to the user.
From the most basic ones forced by a floppy disk to those that only require a mouse click one millimeter higher or lower made deliberately by the user who will be affected, we are going to see everything about malware.
1
What are computer viruses? Definition and examples
Computer viruses are software programs, with a malicious objective that carries with it the alteration in the operationin one way or another, from a computer device, without its user being aware, much less having given their conscious consent for it.
Its operation is quite simple, as is its programming (currently). the base is the execution of software infected with malicious code programmed for a specific purpose. Said execution causes the effects of the code to be triggered, which are very diverse and can be given automatically or programmed.
Among their common characteristics we have:
- They require a significant consumption of resources, which causes cuts in communication, damage to data or slow down equipment.
- They spread by copies and replicas. Internet, of course, makes this characteristic become a brutal evil, because, without connection, all the damage remains on our computer but when it is connected it spreads to the whole world the evil has (if the virus has been programmed for it). .
- Its goal is always harmful to the one who has been infected, either directly or indirectly.
Usually, the first performance of these is the propagation. This is achieved by sending emails automatically or by joining programs that allow such propagation.
In general, what these do, regardless of whether they have already spread or not, is the following:
- Make computers slower (This is a collateral damage of the high consumption of resources of many of them).
- decrease space from our hard drive.
- Launch windows in your operating system to leave it unusable by the user.
- Send messages that will run programs automatically.
- Install software that have been previously modified without your consent.
- generate and send more misleading messages to get new clicks and, with it, the spread of the computer virus.
- corrupt files hosted on our device, from those that we add at will to those that are vital for its operation.
- Download junk content.
- Restart the system (or turn it off) over and over again.
- call contacts and other numbers with additional cost.
- clear the information stored on the hard drive.
- Memorize (or, directly, send in real time) information that the user generates or visits.
- block networks.
They reach our teams in two ways:
- Someone (or something) sends it specifically to us as users. They reach us through the email of infected friends or profiles of other people on various platforms. These emails or messages that we receive are automatic, our acquaintance has not consciously sent anything; We click believing that our acquaintance sends us something in good faith. Another way of sending this malware to us is through emails, this time from strangers, who encourage us to click on them with various lures.
- We are the ones who “seek” it. There is also the case in which we are the ones who are looking for something specific on the net and we come across a file (or even an entire website) corrupted, so we end up executing it thinking that it is something else.
Their study and knowledge of these already occurred before reaching half a century, being John von Neumann a lecturer who talked about “self-replicating computer software” and who published a paper, which was an essay, stating how a program can be designed so that it reproduces itself. This is how the first virus in history was created.
Curiously, the next milestone in this matter occurs with the creation of a game in which one program must compete with another to control it by overwriting or disabling it.
then we have the creation of a virus by the well-known Siemenswhich programmed it in assembler to achieve a deep analysis of it that would allow an exhaustive and deep description to translate it into an article.
Other notable points are the “premonition” of J.Brunner in his novel “The Shockwave Rider“, published in 1975, where he talks about the risk of these malicious programs and their possible impact, the comparison of jugen kraus He makes these, in a university thesis in 1980, regarding biological viruses or the first programming of malware carried out by a 15-year-old minor, whose implementation was carried out by Apple and which is considered the first virus both starting expansion and having a real expansion, that is, that it was extended outside of a theoretical environment or a test.
Characteristics and classification of computer viruses
Depending on the element they infect, we can make a simple classification that includes file infecting cyber virusesboot sector or system infector viruses and Multipartite viruses.
file infectors
Very well defined, they work on the files that we have in our system, both the original ones and those that we are introducing through external devices or downloads.
In turn we can divide them into:
- Resident viruses: These remain dormant in our devices, making use of a small part of our RAM memory, waiting for the right moment to act on the files.
- Direct-acting viruses: They will infect your files when they are booted.
Boot Sector Infectors
These remain in the boot sector of the equipment, on the hard drive, this being your switchboard to launch the attacks
Multiparty
These can work indifferently in any of the above ways and are more dangerous due to their nature of being unpredictable.
How do these cyber viruses really act and what types are there according to their behavior?
On the other hand, we can classify them, this time a little more specifically, based on their behavior. Thus, we find those who are uniform, stealthy, overwrite, encryption, oligomorphic, polymorphic and metamorphic.
uniforms
They are self-replicatingreproducing without control and exponentially affecting the team.
poachers
They act in such a way that the user is not aware of their presence because the symptoms are hidden. This may be temporary and they appear when there is already significant damage or they may never present symptoms until they fulfill their mission.
overwrite
They make use of their code to, once a file is infected, overwrite it at will. In this way, not only is a harmful element installed on our computer, but we lose the functionality of the one it occupies, which becomes a kind of zombie.
of encryption
They work by encrypting your code, either in its entirety or only a part. In this way, it is more difficult to analyze and discover them. This encryption can be of two types.
- fixed encryption: Each new copy of the virus has the same key.
- variable encryption: The encryption code changes for each new copy, so it is more difficult to locate them.
Oligomorphic
They have a few functions and choose among them, randomly, which one to use for stay and run by infecting the computer in question.
polymorphic
For each replica they change their routine, changing sequentially to create harmful copies that, to make matters worse, are different. This implies that they are really difficult to detect and, therefore, they cause great havoc until we manage to realize their existence and, even more, until we manage to eliminate them.
metamorphic
They have the ability to rebuild your code as each replicate is made.
What types of computer viruses are there and which are the most dangerous?
Considering these as products with their own identity, we can find several . Those that we will see below are those considered pure, although, Today we already come across hybrid malwarewith characteristics of each other.
From boot or start
specific name, It is a malware that will infect the partition intended for our operating system to startactivating when we turn on the equipment and the OS is loaded.
of macro
What it does is link the actions to different files so that, at the moment a software loads the file in question, executing its instructions, give priority to those that are related to malware; that is, the virus runs first.
They have characteristics similar to others such as, for example, their code is reproduced when an X situation occurs, it is capable of causing physical damage, it gives specific messages or it emulates any other software; it’s all a matter of programming that is given to him.
Time bomb
They are those who, regardless of their objective, work from an activation that is programmed to happen at a certain time.
trojans
what they do is enter your computer without you noticing, disguised as something else which has an extra code, which is this malicious software. Their objective is to collect data and, after obtaining it, they send it, from the equipment itself, through the network, to a third party.
The Trojan used to install from the performance of another malware installer virus. However, this is no longer done in this way, but rather the user himself who, without knowing it, installs it when executing files that we have downloaded.
A pure Trojan does not replicate, that is, it will not multiply or infect more files; the only way you can have several is by running them one by one, either because they are sent to you or because they are posted on the internet and you download them.
worms
They are those whose goal is its propagation, its replication, even without affecting the systems. This is also produced, without it being necessary to affect file by file, the propagation is done by execution. There are those that only fill your computer and other more sophisticated ones that can also be sent by email, causing contagion to spread in all directions.
The main intention is simply to publicize this evil and, with it, the ability of cybercriminals, possibly looking for create panic and be taken into considerationpreparing the ground for a subsequent attack with other types of malware.
Even so, some, in addition to a very rapid propagation, also have a destructive nature, being capable of damaging…
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