Types of viruses in computer pdf

Very often, computer viruses are run as a part of other programs. This is how the computer types of viruses in computer pdf got its name. In addition

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Very often, computer viruses are run as a part of other programs. This is how the computer types of viruses in computer pdf got its name. In addition to copying itself, a computer virus can also execute instructions that cause harm. Such programs also fit more than one category.

Computer viruses are created for a cause, sometimes they are created to spread political messages and they are also created to hack some system files. Computer viruses are spread through many ways. Some of the types of spreading are: email, removable hardware, downloading and so on. But viruses, are very dangerous. Scripts in web pages that replicate to other webpages. There were no “users”, everyone could do everything. Modern operating systems have the concept of access control.

There can be more than one user and some users may have more “privileges” than others. Certain users may only have access to certain files and are unable to access others. Other users may be able to modify or delete certain files. These privileges can be specified for each file. Another problem is that sometimes the system for rights management may be available, but that it is not used by default. If the code matches, it has likely found a virus. This way of doing things has some problems.

The companies who wrote the antivirus need to keep the virus signatures up to date and need to give this information to the PC that is to be protected. Antivirus software cannot offer full protection, even in the case the virus is known. No matter how many signatures the company has, they will not be able to stop these types of viruses. Instead of knowing each virus by its signature, heuristic antivirus software looks at the behavior of software.

If the software does something that seems bad, the antivirus software stops it. Since every step needs to be watched, this is a very slow way to do things. You can change this page. Please use the preview button before saving. The list of new changes in the wiki. This page was last changed on 8 January 2018, at 20:58.

Unsourced material may be challenged and removed. Malware is defined by its malicious intent, acting against the requirements of the computer user — and so does not include software that causes unintentional harm due to some deficiency. Programs supplied officially by companies can be considered malware if they secretly act against the interests of the computer user. Malware by categories on 16 March 2011. However, malware can be used against individuals to gain information such as personal identification numbers or details, bank or credit card numbers, and passwords.

They can also be hidden and packaged together with unrelated user-installed software. Ransomware affects an infected computer system in some way, and demands payment to bring it back to its normal state. In addition to criminal money-making, malware can be used for sabotage, often for political motives. The best-known types of malware, viruses and worms, are known for the manner in which they spread, rather than any specific types of behavior. These definitions lead to the observation that a virus requires the user to run an infected software or operating system for the virus to spread, whereas a worm spreads itself.

These categories are not mutually exclusive, so malware may use multiple techniques. This section only applies to malware designed to operate undetected, not sabotage and ransomware. Windows or Android devices with a false accusation in harvesting illegal content, trying to scare the victims into paying up a fee. Jisut and SLocker impact Android devices more than other lock-screens, with Jisut making up nearly 60 percent of all Android ransomware detections. A Trojan horse is a malicious program which misrepresents itself to appear useful, routine, or interesting in order to persuade a victim to install it. While Trojan horses and backdoors are not easily detectable by themselves, computers may appear to run slower due to heavy processor or network usage.

Unlike computer viruses and worms, Trojan horses generally do not attempt to inject themselves into other files or otherwise propagate themselves. Mac-OS keychain, and password vaults. Once malicious software is installed on a system, it is essential that it stays concealed, to avoid detection. Some malicious software contains routines to defend against removal, not merely to hide themselves. Each ghost-job would detect the fact that the other had been killed, and would start a new copy of the recently stopped program within a few milliseconds. The idea has often been suggested that computer manufacturers preinstall backdoors on their systems to provide technical support for customers, but this has never been reliably verified. It was reported in 2014 that US government agencies had been diverting computers purchased by those considered “targets” to secret workshops where software or hardware permitting remote access by the agency was installed, considered to be among the most productive operations to obtain access to networks around the world.

Since the beginning of 2015, a sizable portion of malware utilizes a combination of many techniques designed to avoid detection and analysis. The second most common evasion technique is confusing automated tools’ detection methods. The third most common evasion technique is timing-based evasion. This is when malware runs at certain times or following certain actions taken by the user, so it executes during certain vulnerable periods, such as during the boot process, while remaining dormant the rest of the time.

The fourth most common evasion technique is done by obfuscating internal data so that automated tools do not detect the malware. Sometimes even installing new versions of such plugins does not automatically uninstall old versions. PC for vulnerable out-of-date software, and attempt to update it. DVD-ROM, USB flash drive or network.