Hidden Internet Risks and How to Manage Them 1
What is computer virus?
What are the basic measures to take?
What is computer virus?
Virus
Virus (or computer virus) refers to unauthorized, malicious program which infects devices such as computer and smartphone.
It is called virus because it has the functionality to infect, hide, and develop (illness) just as viruses contagious between people.
Largely, there are three types of viruses.
Parasitic virus
Virus may be hidden in files used in your computer.
Your computer can be infected by opening or executing the file.
Trojan horse
It disguises as handy software or harmless program to intrude into your computer and destroys from the inside.
Users may welcome the program on their own since it pretends to be useful or necessary.
Worm
It propagates repeatedly on its own using the network to destroy your computer.
It fully uses the three most infectious routes of the internet (email, website, and unauthorized access) to create and scatter its own copy.
Source of infection
Virus infects devices from various routes.
The most infectious routes are as follows.
Your computer gets infected by opening an attachment or reading an email in HTML format.
Currently, most infections are through email.
Websites
A virus is embedded in a program working on a website and your computer gets infected by viewing such website or downloading a file from the website.
Unauthorized access
Your computer gets infected by those who access your device through a security hole of your OS’ communication function.
File replacement, other factors
Your computer gets infected through file exchanging software or messengers via the internet.
Your computer also may get infected by exchanging files using storage media (CD-ROM, USB memory stick, etc.) instead through the internet.
Examples of infected computer
When your computer is virus-infected, it may cause the following situations.
- Normal behaviors (e.g., show messages on the screen, play music, etc.) cannot be performed.
- It takes time to start the computer or may not be able to boot up.
- Saved data and hardware may get destroyed, or data may be sent out.
- Programs may come to an automatic halt and stop moving.
- Enormous amounts of email may be sent out without the user’s intent.
Not only your computer may get destroyed, but you may cause damage to many other people via the internet, becoming a perpetrator as a result. It is important to take the necessary measures to prevent from getting infected even when you are not virus infected.
The basic must-dos
This section gives you information on the basic must-dos in order to prevent your device from being infected with a virus.
On a daily basis
- Do not open an email with an attachment carelessly (or do not execute the attachment).
- Do not open an email with an address or subject which you are not sure of (or do not execute the attachment).
- Do not open an email with blank or unknown title (or do not execute the attachment).
Keep your mailer up to date as much as possible
In order to use Asahi Net’s Mail Service, make sure to keep your mailer up to date. OS and mailer which are no longer supported are extremely dangerous from a security point of view.
Please note that Asahi Net cannot give guidance on how to set up OS or mailer which is no longer supported.
See the following page for OS and mailer which are no longer supported.
Set your mailer not to show preview
There are some viruses which are executed by just viewing the content of the email in preview mode. It is recommended to change your settings not to use the preview functionality.
Use a virus scan service
The mail you receive may be sent from a device which is infected with virus.
For such a reason, you need to perform a virus scan before receiving such an email. Please apply for the following service.
Scan your computer
Latest viruses or subvariants of known viruses may intrude into your computer by breaking through the above-mentioned prevention measures.
There are also viruses which intrude into your computer when you visit a website or download something.
To prevent those factors, please install a security software/service/plugin.
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