Malware - An Overview
Reading Time: 4 min | February 01, 2022
Malware is the umbrella term for software that installs itself on a computer system and often causes extensive damage. There are different types of malware, each with different objectives. The following provides an overview of some of the most important malware types.
Either read the full article or jump directly to a category that interests you:
1. Computer virus
2. Computer worm
3. Trojan
4. Backdoor
5. Spyware
6. Ransomware
7. Protective measures
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1. Computer Virus
A computer virus is perhaps the most well-known form of malware, although often mistakenly equated with the umbrella term malware itself.
A computer virus is a program that can spread itself autonomously on the infected device.
Just like in real life, the virus needs a host, such as a file or software, that the virus can infect.
It is important to note that a virus can only be installed with the help of the user, or transferred to other computer systems with the help of a user. This can happen, for example, when a user starts an infected program or forwards an infected file via email.
2. Computerwurm
A computer worm is similar to a virus. However, unlike a virus, a worm does not need a host and can also spread autonomously.
A worm uses existing data transmission channels, such as email programs, to spread itself.
"I Love You" worm
One of the biggest computer worm attacks was the "I love you" worm in May 2000. The worm infected approximately 500,000 computers and caused about $10 billion in damages.The worm was disguised as a love letter attached to an email with the subject "I love You". Once the user opened this letter, the worm installed itself and sent itself with the same type of email to all of the user's contacts. This way, the worm spread rapidly.
The worm modified system-critical files, causing many networks to come to a standstill.
3. Trojaner
Trojan horses, like computer viruses, can only be installed with the help of a user.
Trojans are often installed via email attachments or seemingly useful programs, such as Trojans disguised as antivirus software.
Once on a system, Trojans can replicate themselves independently.
Emotet
One well-known and highly dangerous Trojan horse is Emotet, first discovered in 2014.Initially, the Trojan attacked not only private users but also companies, organizations, and authorities. For example, in 2018, Emotet infected the Fürstenfeldbruck hospital, which had to disconnect from the emergency services.
Emotet usually infects devices via phishing emails and often downloads further malware, such as ransomware.
Today, Emotet infections are mostly limited to private individuals.
4. Backdoor
A backdoor is essentially a secret entrance that hackers can use to access a computer system. Through such a backdoor, hackers have unrestricted access and can, for example, load further malware onto the system. They also have access to the entire activity on the computer, such as keystrokes, website visits, and even access to the computer's camera and microphone.
Code Red 2
A well-known attack through a backdoor was the Code Red 2 computer worm. It exploited a vulnerability in Microsoft.Due to a programming error, hackers could have unrestricted access to the affected computers and execute commands. Due to the backdoor, even a restart did not help here.
5. Spyware
Spyware, as the name suggests, spies on the user. The spyware can install itself independently or gain access to the device with the user's help.
Spyware records the activities on the device and then passes them on to third parties. These can be browser history, email traffic, screen recordings, and even microphone and camera recordings.
Since such espionage activities take up a lot of computing power, an infected computer usually slows down significantly.
6. Ransomware
Ransomware is a type of malware that encrypts data or entire systems and only releases them in exchange for a ransom payment.
Today, most ransom payments are made through Bitcoin, and there is no guarantee that the data will be accessible again after payment.
WannaCry
One well-known ransomware is WannaCry. It was one of the biggest attacks to date, encrypting more than 200,000 computers in over 150 countries.The attack lasted a total of four days, and among the victims were critical systems such as a hospital system including medical equipment.
Here you can find more information on how leitzcloud can help protect you from ransomware.
7. Protective Measures
There are several things you can do to minimize the risk of a malware attack:
- Have an up-to-date antivirus program
- Always have the latest system updates (security vulnerabilities are fixed here directly)
- Be cautious with email attachments and program downloads
- Do not always log in with administrator rights, as this makes it more difficult for malware to introduce system-wide changes
- Be careful when exchanging data (regardless of what type of data, all could theoretically be infected)
- Have a backup of your files (if you are still attacked, your data is still there)
leitzcloud can help you protect yourself against malware attacks.
With LeitzCloud, your files are always secure on our servers, and you can easily share files of any type with external parties, avoiding email attachments altogether.
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Sources:
AVG: What is a computer virus? (Accessed 24.01.2022)
Kaspersky: What is a Trojan and what damage can it do? (Accessed 24.01.2022)
Hornetsecurity: Computer worm (Accessed 24.01.2022)
What is malware?: Backdoor - The back door to your computer (Accessed 24.01.2022)
Security Insider: What is Spyware? (Accessed 24.01.2022)
BSI: Ransomware - Beware of extortion software (Accessed 24.01.2022)
Spiegel: How a computer worm ate through mailboxes 20 years ago (Accessed 24.01.2022)
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