How do computer viruses spread? And how can you protect your device with antivirus?
Here are some common ways computers can get infected with a virus:
Email viruses
E-mail is one of the most popular means of spreading computer viruses around the world. You can catch computer viruses via email in the following ways:
• You open an attachment . Such a file often has a seemingly harmless name (like " Your flight plan ") and it is an executable file (.com, .exe, .zip, .dll, .pif, .vbs, .js, .scr) or a macro file (.doc, .dot, .xls, .xlt, xlsm, .xsltm ...).
• You open an e-mail with an infected part of the text. In these days of graphics, colors, and bells and whistles, some viruses are carried in the HTML text of the email itself. By default, many email services disable HTML until you confirm that you trust the sender.
Instant messaging viruses
Instant messaging (IM) is another means of spreading viruses. Skype, Facebook Messenger, Windows Live Messenger, and other IM services are inadvertently used to spread viruses to your contacts using infected links via chat messages.
These instant messaging and social media viruses spread quickly and widely, as people are much more likely to click a link when it is in a trusted person's message than in a stranger's email.
File sharing viruses
Peer-to-peer file-sharing services such as Dropbox, SharePoint, or ShareFile can also be used to spread viruses. These services synchronize files and folders with every computer associated with a particular account. So if someone (accidentally or not) uploads a virus-infected file to a file-sharing account, the virus will be downloaded to everyone else with access to that shared folder.
Some file-sharing services, like Google Drive, scan uploaded files for viruses (although they only scan files less than 25MB, making it easy for virus distributors - they just need to make sure their infected files are larger).
However, most of the other services do not perform virus scanning at all. So it is your responsibility to ensure that you are protected from any potential threats posed by a downloaded file.
Software download viruses
Counterfeit antivirus programs are one of the most common types of virus-contaminated software downloads. Scammers and cybercriminals use aggressive pop-ups and advertisements to trick users into believing that a virus has been found on their PC and then force them to download their "antivirus software" to remove the threat.
Instead of ridding the computer of viruses, this fake antivirus infects the PC with malware, often with devastating consequences for the victim's files, hard drive, and personal information.
Vulnerable software without patches
Finally, one of the most widely used (yet mostly overlooked) methods of spreading viruses: out-of-date software.
This includes software and apps that have not been updated with the latest security updates from the developer to close security holes in the software itself.
Software without patches poses a major cybersecurity problem for companies and organizations. But with criminals exploiting vulnerabilities in outdated versions of popular programs such as Adobe Reader, Java, Microsoft Windows, or Microsoft Office, private users are not safe from infection either.
Types of computer viruses
Here is a list of the different types of computer viruses that are currently prevalent:
Boot sector virus
The boot sector is the part of your PC's hard drive that loads your computer's operating system, e.g. B. Microsoft Windows. A boot sector virus infects the master boot record (MBR), so the virus is loaded into computer memory during startup.
Boot sector viruses used to be spread mainly via removable media such as USB sticks, floppy disks, and CD-ROMs. As technology advances, boot sector viruses are becoming rarer and mostly appear as email attachments these days.
Examples of boot sector viruses:
• Elk Cloner: This virus from the early 1980s was attached to a game. When the game was started for the 50th time, the virus displayed a poem on the screen.
• Stoned: The first variant displayed messages on the screen asking for marijuana to be legalized. Its signature (although not the virus itself) reappeared on the Bitcoin blockchain in 2014.
• Parity Boot: Another "vintage" virus that was one of the most common types of computer viruses in Germany until 1996.
• Brain: Considered the first computer virus for MS-DOS, this virus was created by the Pakistani brothers Alvi to protect their medical software from copyright infringement - an attempt that, to their annoyance, quickly got out of control.
• Michelangelo: Every year on March 6th (the birthday of artist Michelangelo) this virus came to life and zeros out the first 100 sectors of a hard drive, making it impossible for ordinary users to access their files.
Direct Action Virus
This type of virus is designed to “roam” your computer: it invades, generally distributes itself to files of a certain type (usually COM or EXE files), and then deletes itself. This is the most common type of virus and easiest to program - but also easiest to eliminate.
Examples of direct action viruses:
• Win64.Rugrat: Also known as the Rugrat virus, this early example of direct action virus that could infect any 64-bit executable file is found in the directory and subdirectories in which it was started.
• Vienna virus: This differs from others in that it was the first to be destroyed by an antivirus program. It looks for .com files and deletes some of them while trying to infect them.
Memory resident virus
In contrast to the direct-action viruses already mentioned, memory-resident viruses nestle in the computer's primary memory (RAM). This is bad news because it can still be active in secret, even after you've removed the original infector. Some are fast, others are slow, making them harder to spot.
Examples of memory-resident viruses:
• Jerusalem Virus (also called "Friday the 13th"): After finding its way into RAM and hiding in it, this virus deleted programs from your computer or inflated the size of infected programs on Friday the 13th until they could no longer be carried out.
• One-half Virus: Sometimes referred to as Freelove Virus or “Slovak Bomber”, this virus gradually encrypts your hard drive on its way. As soon as he's done halfway (and on the 4th, 8th, 10th, 14th, 18th, 20th, 24th, 28th, and 30th day of each month), the message “Dis is one half . Press any key to continue ... "is displayed.
• Magistr Virus: This very aggressive virus emails itself to your contact list, deleting every other file, destroying your CMOS and BIOS - and displaying offensive messages.
Multipartite virus
These extremely versatile viruses double their potential for spreading by attacking both files and the boot sector. This way, even after successfully removing all infected files on the computer, they will remain hidden in the boot sector and can be started again. If you clean up the boot sector, it will be re-infected via an infected file.
Examples of multipartite viruses:
• Junkie Virus: This multipartite virus was transmitted in a file called HV-PSPTC.ZIP, which was said to be the computer game "Pacific Strike". Of course, it wasn't.
• Tequila Virus: This virus avoids files with names containing the letters “v” and “sc” and likes to display the message “BEER and TEQUILA forever!”.
• Invader Virus: This virus starts off with a pleasant Mozart tune, but as soon as you press the key combination CTRL + ALT + DEL to restart, it overwrites the first line of the hard disk with a copy of the virus.
Polymorphic Virus
These are the mutants of the computer virus world. They change shape to avoid detection while maintaining their basic threat potential. After infecting your files, the viruses replicate in a slightly different way - making them very difficult to fully detect and remove.
Examples of polymorphic viruses:
• Satanbug Virus: Despite its name, this polymorphic virus is not deliberately harmful to your files, but with up to nine levels of encryption, virus scanners find it difficult to remove.
• VirLock virus: Part ransomware, part polymorphic virus, the Win32 / VirLock virus encrypts files and demands a ransom - but changes its form every time it is spread.
Macro virus
Some viruses are written in a macro language with the aim of embedding them in software that allows macro applets such as Microsoft Word. This means that viruses in Word documents can infect your PC.
Examples of macro viruses:
• Melissa: Distributed through email attachments. As soon as this virus infects your PC, it attacks your Microsoft Outlook e-mail client and automatically sends itself to the first 50 contacts in your address book, which may slow down servers in a chain reaction or even disable them completely.
How do I protect myself from viruses?
First of all, we can state that you do not want to know any of these viruses near your files, your hard drive, or your network. Now let's get to how you can prevent computer viruses in the first place.
It is imperative that you have antivirus software installed on your PC and smartphone.
Point.
An
antivirus is your first line of defense against viruses and a host of other malware that you really don't want to deal with. Now, if you believe that viruses are bad (and they are in the day), then there are far worse things.
There is no excuse. But you don't want to spend any money? There is some excellent free antivirus software out there (ahem). Worried about the software slowing down your PC? Ours is so resource-efficient that you won't even notice that it is running on your PC.
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