What is malware?

What is malware?malicious + software = malware

- Classification : virus, greyware, trojan horses, dialer, rootkit, bootkit, key-logger, botnet, backdoors,
                         ransomware, adware, spyware, data-stealing malware, worm, etc..
         
                         Malware, short for malicious software, is software to help hackers disrupt users computer

                         operation, gather sensitive information, or gain unauthorized access to a computer system.

                         While it is often software, it can also appear in the form of script or code.

                         Malware is a general term used by computer professionals to mean a variety of forms of

                         hostile, intrusive, or annoying software or code. 

 

                          -from en.wikipedia.org

Virus : A computer virus is a small piece of code that spreads, without the owner permission or knowledge,
           by coping it self in a particular section of the hard disk, or in a specific program or document,  in

           order to be executed every time the infected file is opened.

 

trojan horses : With the multitude of adobe reader exploits, Malware included in PDF file has become a

                         real plague and is indeed one of the most common ways to infiltrate a network.
                         Trojan horses can carry any kind of malware, howerver, from an ethical hacking point of

                          view, the most common are Backdoors.

Rootkit : A rootkit is a malware which is designed to hide itself to the user and to the antivirus program
              in order to completely subvert the OS functioning.

Bootkit : Bootkits are rootkis which circumvent OS protection mechanisms by executing at bootstrap.

Backdoors : A backdoor in a computer system (or cryptosystem or algorithm) is a method of bypassing

                     normal authentication, securing remote access to a computer, obtaining access to plaintext,

                     and so on, while attempting to remain undetected.
                     The backdoor may take the form of an installed program (e.g., Back Orifice) or may subvert

                     the system through a rootkit.

Adware : Adware are annoying software that show advertisement to the user.

Spyware : Spyware is software used to collect information about the OS, visited websites, passwords, and

                  so on. The information is sent back to a log collection server owned by the developer.

Greyware : Greyware is a general term used to indicate a Malware.

                    It can be either a spyware or adware or both.

Dialer : A dialer is a software that tries to dial in bumbers on dial up connections in order to collect money

              from the victim's phone bill.

key-logger : Keystroke logging (often called keylogging or "keyloggers") is the action of tracking

                     the keys struck on a keyboard, typically in a covert manner so that the person using the

                     keyboard is unaware that their actions are being monitored.
                     There are numerous keylogging methods, ranging from hardware and software-based

                     approaches to electromagnetic and acoustic analysis.

Botnet : A botnet is a collection of compromised computers, each of which is known as a 'bot', connected

              to the Internet.
              When a computer is compromised by an attacker, there is often code within the malware that

              commands it to become part of a botnet.
              The "botmaster" or "bot herder" controls these compromised computers via standards-based

              network protocols such as IRC and http.

Ransomware : Ransomware is a software that encrypts personal information with passwords, (such as

                         bank account). After that, asks the user to send money in order to have the important

                         information unlocked.

Data-stealing malware : Data-stealing malware is a web threat that divest victims of personal and

                                         proprietary information with the purpose of monetizing stolen data through direct

                                         use or underground distribution. Content security threats that fall under this

                                         umbrella include keyloggers, screen scrapers, spyware, adware, backdoors, and

                                         bots.
                                         The term does not refer to activities such as spam, phishing, DNS poisoning,

                                         SEO abuse, etc. However, when these threats result in file download or direct

                                         installation, as most hybrid attacks do, files that act as agents to proxy

                                         information will fall into the data-stealing malware category.

Worm : Usually worms are part of other malware such as rootkit, and they offer an entry point into the

              system.