In the tech industry malware is a big issue. And in present day anyone can get malware regardless of the Operating System or hardware. This makes it even more important to know how hackers can infect their targets.
Anti Virus Software
Of course it is true most viruses are written with a specific target in mind. So many virus writers will write a virus for the most commonly used technology. However they may also have certain goals that require virus for a specific platform. They also may rewrite the virus for one platform to work with another platform. And of course if the virus writer wrote the virus code from the ground up and hasn’t given anti-virus companies enough time to find the virus to update their database, then the virus wont be detected by any anti-virus software.
Disclaimer: Even though it is legal to bind files, it is illegal to bind malicious files in the attempts to commit unlawful acts against others. I take no responsibilties for the readers actions.
Of course the virus needs to be installed on the system first. This becomes a great challenge since a Windows user wont just install any .exe file, especially if the .exe file is very small in size. Simply because that pretty screams something fishy to Windows users. And the same goes for mac users and their .dmg files or the linux users, android users and iOS users.
Virus writers who know this will usually bind their virus with trust worthy files. Lets say the virus writer knows most people will have no problem clicking on a .jpg file or a .mp3 file. And lets say we know many people will click on a .jpg file called awesome_image.jpg or awesome_music.mp3. Then the virus writer will bind the virus to such a file. The great thing about this for a virus writer is the ability to do this requires tools that ship with every OS. Simply because there is legitimate reasons to use such tools.
The virus writer simply needs two files he or she wants to bind together then issue the following command.
Windows Command Line
copy /b virus.exe + image.jpg new-image.jpg
Linux and Mac and other *nix systems
cat virus image.jpg > new-image.jpg
Now the virus writer could make his or her virus bind itself to other files on the system at given times. For example the virus writer could write the virus to monitor and record processes and how frequently a file is opened and viewed or copied and pasted to a different location or sent to a different location. And have the virus bind itself to those files.
So lets say the virus writer convinces Joe to view an image which has the virus binded to it, which infects his computer. Now the virus monitors files he sends via email regularly. Lets say Joe is a writer for his local newspaper. The virus notices he usually sends Microsoft Word Documents to E-Mails. So the virus binds itself to new .doc files and .docx files.
Now Joe sends one of his Microsoft Word files to his job. They open the file up and since the virus is new and not currently in any anti virus databases. The News Paper company doesn’t get alerted. They then become infected.
The virus notices images are often used on the news paper companies computers. And the news paper company has free articles on the internet. Now the news paper company uploads the new article that joe just wrote along with some images to their server. Now when people open the article up in their web browser the infected files the news paper company uploaded start to infect the readers who view it in their browser, causing an epidemic.
This continues until Anti Virus companies find a fix for the virus, usually by deliberately infecting a system in a controlled state. And examining and dissecting the virus. Once they figure out how the virus works they can figure out how to fix it and offer it to their customers. They then add the virus to their database which identifies the code in the virus so the AV’s can prevent the virus from spreading.