Ransomware
Ransomware is a type of malware that encrypts a victims files and demands a ransom fee, usually in crypto for them to get their files back. An example of ransomware is LockBit, which is a RaaS (Ransomware as a Service), which means the ransomware is bought by other cybercriminals, and those cybercriminals will use it to attack companies and receive a cut of the ransom. Ransomware in general is considered the most dangerous/impactful type of malware, as it causes the most damage to infrastructure and can cost companies millions of dollars. An example of this would be the Post Office ransomware attack that was performed by LockBit in January 2023, they were demanding a fee of $80 million. Methods of Infection: Phishing emails, social engineering.
Trojan
A trojan malware is a type of malware that pretends to be a legitimate software or something useful, but in reality, it is malicious and designed to infect the user by tricking them into running the program. Trojans differ from viruses because they do not self replicate, and are spread through social engineering, which is where you manipulate people into thinking that it is some kind of cheat or mod for a game, when in reality it is a trojan. Once the trojan is executed, it will give the attacker the ability to allow them to remotely control the computer, steal data, or install more malware onto the system. Often attackers will use trojans to create a backdoor into the system, ultimately turning the system into a "Zombie" within a botnet. Methods of Infection: Phishing emails, social engineering.
Virus
A computer virus is a type of malware that is made to spread automatically (self replicate) by inserting a copy of itself into other programs and files on the system. Once a virus has been executed, it will spread throughout the entire system. The way a virus self replicates, is different to that of a Worm, a virus will attach itself to a host file, or the boot sector, and when the host file is executed, the virus will also be executed. The virus will then search for other files to infect, and the cycle will continue. The main goal of a virus is to cause damage to the system, and to spread to other systems, causing more damage. Methods of Infection: Phishing Emails, Social Engineering, Infected USB Drives (outdated), Self Replicating.
Spyware
Spyware is a type of malware that is designed to spy on the victim, and slowly gather information on them. Spyware gathers information on a user without the user knowing, and the user is also infected without their knowledge. Spyware can gather information such as browsing history, bookmarks, usernames, passwords, and sometimes even financial information. Spyware can also be used to gather information on a companies employees, to allow the attacker to determine weak spots in a company, to allow for further attacks such as ransomware (ransomware is usually the end goal). Methods of Infection: Phishing Emails, Malicious Browser Extensions, Bundled with Freeware or Pirated Software, Exploiting Vulnerabilities.
Info Stealer
An Infostealer is a malicious program that is designed to steal sensitive information from a victims computer, and then sell that information, or use it to extort the victim for financial gain. Infostealers are often used by cybercriminals to gather PII (Personally Identifiable Information), on a companies employees, or customers, and then either sell that information, or use it to gain access to the companies network, allowing more malware to be deployed for example Ransomware. Infostealers can also be used to steal financial information, such as credit card numbers, and bank account information. Often with this malware, the information that is stolen is sent to a C2 server, where the attacker can then access that information, and do whatever they please with it. Methods of Infection: Phishing Emails, Fake Software/Keygens, Exploit Kits, Malicious Chrome Extensions, Trojans.
Computer Worm
A Computer Worm is a type of malicious software that is designed to spread across systems and networks autonomously. Worms are different from viruses because they do not require a hosts file to self replicate, they solely rely on vulnerabilities in the system, and it then exploits those vulnerabilities to spread. Worms can spread through email, instant messaging, and file sharing networks. Once a worm has gotten into the system, it will start creating many copies of itself (self replicate) and then it will begin spreading to other systems on the network, The main purpose of a computer worm is to spread to different systems and networks, and then to cause damage to the entire system, and the massive web of systems it has infected. Methods of Infection: Exploit Software Vulnerabilities, Email, NFS (Network File Sharing), Weak Passwords, Drive by Downloads (Compromised Sites).