Computer Virus

Definition of a Computer Virus

The word "virus" comes from Latin and means "poison" or "mud." Although these terms may be unpleasant, they accurately describe the results of a computer virus when it infects your PC. In the worst case, a virus can cause a complete system failure.

Fred Cohen, an American who programmed the first PC virus in 1983, can be considered the origin of computer viruses. These viruses can infiltrate other applications and programs almost undetected and then spread to other machines. Although Fred Cohen is now a computer security researcher and professor at New Haven University in West Haven, the viral code he developed laid the foundation for many of today's dangerous computer viruses.

How exactly does a computer virus work? Technically, a computer virus is a self-replicating computer program. The feature that distinguishes computer viruses from other types of malicious software is their ability to spread without your permission. A computer virus infiltrates other computer programs and spreads to other systems, causing changes in the operating system or damaging other programs. During this process, the end user often suffers data loss, and even damage to hardware. Unlike so-called computer worms, a computer virus generally spreads only locally and much more slowly, hence causing less overall damage.

How are computer viruses created and what are they used for? First of all, computer viruses do not develop on their own, but are generally programmed to intentionally harm computers, systems, and even entire networks.

However, the first computer viruses in history were relatively harmless. Known early viruses such as the Creeper virus (1971) or the Ika-Tako virus were simply programmed to annoy people or draw attention to themselves.

However, other computer viruses that emerged over the years were designed to cause excessive harm to their victims.

In addition, there are "well-intentioned" viruses that programmers aim to discover security vulnerabilities in certain companies' systems or even governments. In contrast, the goal is to improve security measures so that future more malicious PC viruses can be withstood.

Additionally, there are also "benign" PC viruses such as the Cruncher virus that compresses any infected file and thus frees up space on the hard drive. However, these types of "benign" viruses are clearly more numerous.

The advantage for programmers* in using computer viruses is that it is rarely possible to determine where the virus came from.

Types of Computer Viruses

In general, two different types of computer viruses can be distinguished based on their method of infection: PC viruses that infect files and viruses that copy themselves in the boot sector. The advantage of boot sector viruses is that they are activated directly at system startup.

Program viruses are divided into two categories: non-subscription and subscription viruses. The former is placed at the beginning or end of an executable file, but the size of the file is changed by the virus attachment. Overwriting viruses do not change the size of the file, as this type of computer virus writes over the beginning of the file.

For example, there are also viruses that call other viruses that add a link type to the infected file. This leads to the real hidden virus on the PC.

Protection Against Computer Viruses?

This is a question that employs many people and companies. One thing is certain: complete protection against computer viruses is theoretically only possible if the PC is completely isolated from external data. However, this would mean avoiding file exchanges via USB drives, CDs, or the Internet. Therefore, this approach is not very practical.

An effective method in combating PC viruses is to be cautious when dealing with Internet sources. This means, for example, that you should not open email attachments or files from unknown sources. You should also use a spam and malicious software filter for your inbox.

If computer viruses reach your computer, anti-virus programs can detect, block, and fight against the malicious software. Anti-virus tools available on the market can be divided into three types: real-time scanners, manual scanners, and online scanners.

Real-time scanners work directly on the computer in the background. As their name suggests, they operate in real time and continuously scan memory, all programs running on the PC, and data traffic. As soon as the anti-virus program detects the signature of malicious software, it prevents the user from accessing the targeted data. * After that, they have the option to move, delete, or repair the data to a quarantine directory. The quarantine directory is a separate area on the computer from the rest of the system. This area is used to monitor what the software does to the operating system—if it causes damage, the anti-virus program removes the malicious software. Hornetsecurity Advanced Threat Protection also works on the same principle.

Manual scanners also work similarly, but instead of being continuously active, they start a PC virus scan when triggered by an manual request from the user or according to a timer set by the user. The anti-virus program then scans all data on the computer for malicious software and informs the user* about the results.

The unique feature of online scanners is that they upload virus signatures and program codes to the Internet and check the data on your PC based on the information found. To use an online scanner, you must have an Internet connection. Online scanners are generally used together with installed anti-virus software.

Important: Since new forms of computer viruses with new virus signatures are continuously created, anti-virus tools should always be kept up to date. It also makes sense to keep your operating system on your computer continuously updated, as old operating systems often have security vulnerabilities that are targeted by computer viruses. These security vulnerabilities are usually fixed in patches, so regular updates are very important.

Another form of virus detection is a checksum that stores data in specific sections and saves it in a special file. During subsequent checks, the last saved file is compared with the current status. If a discrepancy is found between the two files, the program warns users about a possible computer virus infection.

In principle, it is recommended to back up all files to prevent irreversible data loss in the event of a computer virus.

Protecting Your Email Inbox

Computer worms generally spread to computers via email, for example through a phishing email. You can protect yourself from malicious software before it enters your computer by identifying threats. This includes, for example, companies like Hornetsecurity's Spam Filtering and Malware Protection or Advanced Threat Protection.

Legal Aspects of Computer Viruses

The consequences of computer viruses caused by hackers are not clearly formulated in the law. For example, in Switzerland, programming or spreading a computer virus and exploiting it can be punished with up to five years in prison. In Germany and Austria, there are no exact regulations on this subject, and the legal situation is more ambiguous. In any case, changing data in a computer system with a virus is a punishable offense, although the exact penalty depends on judicial discretion.

How to Develop IT Security Through Security Awareness?

When attackers try to exploit technical or human security vulnerabilities, employees are the first line of defense. Companies reduce the risk of becoming victims of phishing attacks by educating their employees. Hornetsecurity's Security Awareness Service provides automatic Security Awareness Training and phishing simulations.

Source: Computer Virus - What is a computer virus and how to protect yourself (hornetsecurity.com)