Skip to content. Change Language. Related Articles. Computer Network Fundamentals. Physical layer. Data Link layer. Network layer. Transport layer. Application layer. Network Security. Computer Network Quizes. Table of Contents.
Improve Article. Save Article. Like Article. A virus is a fragment of code embedded in a legitimate program. Viruses are self-replicating and are designed to infect other programs. They can wreak havoc in a system by modifying or destroying files causing system crashes and program malfunctions. On reaching the target machine a virus dropper usually a trojan horse inserts the virus into the system.
For more details, refer to this. Various types of viruses: File Virus: This type of virus infects the system by appending itself to the end of a file. Trojans are also known to create backdoors to give malicious users access to the system. Unlike viruses and worms, Trojans do not reproduce by infecting other files nor do they self-replicate. Trojans must spread through user interaction such as opening an email attachment or downloading and running a file from the Internet.
Bots often automate tasks and provide information or services that would otherwise be conducted by a human being. They may also be used to interact dynamically with websites. Bots can be used for either good or malicious intent. In addition to the worm-like ability to self-propagate, bots can include the ability to log keystrokes, gather passwords, capture and analyze packets, gather financial information, launch Denial of Service DOS Attacks , relay spam, and open backdoors on the infected host.
Bots have all the advantages of worms, but are generally much more versatile in their infection vector and are often modified within hours of publication of a new exploit. They have been known to exploit backdoors opened by worms and viruses, which allows them to access networks that have good perimeter control. Bots rarely announce their presence with high scan rates that damage network infrastructure; instead, they infect networks in a way that escapes immediate notice.
Advanced botnets may take advantage of common internet of things IOT devices such as home electronics or appliances to increase automated attacks. Crypto mining is a common use of these bots for nefarious purposes. Advanced malware typically comes via the following distribution channels to a computer or network:. A set of stealthy and continuous computer hacking processes, often orchestrated by a person or persons targeting a specific entity.
An APT usually targets either private organizations, states, or both for business or political motives. APT processes require a high degree of covertness over a long period of time. The "advanced" process signifies sophisticated techniques using malware to exploit vulnerabilities in systems. The "persistent" process suggests that an external command and control system is continuously monitoring and extracting data from a specific target.
The "threat" process indicates human involvement in orchestrating the attack. Software that generates revenue for its developer by automatically generating online advertisements in the user interface of the software or on a screen presented to the user during the installation process.
The software may generate two types of revenue: one is for the display of the advertisement and another on a "pay-per-click" basis if the user clicks on the advertisement. An undocumented way of accessing a system, bypassing the normal authentication mechanisms. Some backdoors are placed in the software by the original programmer and others are placed on systems through a system compromise, such as a virus or worm.
Usually, attackers use backdoors for easier and continued access to a system after it has been compromised. Adversaries may use bootkits to persist on systems at a layer below the operating system, which may make it difficult to perform full remediation unless an organization suspects one was used and can act accordingly. Software that modifies a web browser's settings without a user's permission to inject unwanted advertising into the user's browser.
A browser hijacker may replace the existing home page, error page, or search engine with its own. These are generally used to force hits to a particular website, increasing its advertising revenue. This software often comes in the form of a browser toolbar and is received through an email attachment or file download.
A class of malware designed specifically to automate cybercrime. Crimeware distinct from spyware and adware is designed to perpetrate identity theft through social engineering or technical stealth in order to access a computer user's financial and retail accounts for the purpose of taking funds from those accounts or completing unauthorized transactions that enrich the cyberthief.
Alternatively, crimeware may steal confidential or sensitive corporate information. Malicious attempts by one or more people to cause the victim, site, or node to deny service to its customers. A computer file that contains a sequence of instructions to run an automatic task when the user clicks the file icon or when it is launched via a command. Applications for personal or business communication that are built around the concept of online presence detection to determine when an entity can communicate.
These applications allow for collaboration via text chat, audio, video or file transfer. The action of recording logging the keys struck on a keyboard, typically covertly, so that the person using the keyboard is unaware that their actions are being monitored.
Data can then be retrieved by the person operating the logging program. A keylogger can be either software or hardware.
Software that uses system resources to solve large mathematical calculations that result in some amount of cryptocurrency being awarded to the solvers. There are two ways that mining can be performed: either with a standalone miner or by leveraging mining pools. Mining software relies on both CPU resources and electricity.
Like a human virus, and also like Trojan Horses, a computer virus can range in the damage it causes. Some may cause only mildly annoying effects while others can damage your hardware, software or files. Like Trojans, almost all viruses are attached to an executable file.
This means that it could be present on a computer but may not actually infect it unless a malicious program is run or opened. Also similar to human viruses, a computer virus cannot be spread without human action, such as running an infected program, to keep it going. As a result, viruses are often spread by individuals who unknowingly send on infected files to others as attachments in emails. It is always recommended to use an anti-virus solution.
Furthermore, that software solution must always be kept up to date in order to ensure any vulnerabilities are kept patched and able to block out any known threats. Learn more on how to stay protected from the latest Ransomware Pandemic. Cyber Hub Cybersecurity What is a Virus.
0コメント