Malware, or malicious software, is a program or file designed to disturb computer processes and operations or gain entrée to the computer system without the user’s knowledge or permission. Malware has become a common term for all hostile or intrusive software, computer viruses, worms, Trojan horses, ransomware, spyware, adware, scareware, and other malicious programs.
The above-mentioned malware and malicious software programs can perform a variety of functions, including stealing, encrypting, or deleting sensitive data, altering or hijacking core computing functions, and monitoring users’ computer activity without their permission. Cybercriminals target users’ end devices through the installation of malware.
Viruses
A virus is an executable code attached to another executable file. Most viruses require end-user initiation and can start at a particular time or date. They generally spread in one of three ways.
- Removable media
- Downloads off the Internet
- Email attachments
Detecting a virus is not easy. The viruses can be harmless and just show a picture, or they can be destructive, such as those that change or delete data. To avoid detection, a virus changes itself into other shapes. A simple process of opening a file can trigger a virus.
The USB drive is the primary source of spreading a virus. A boot sector, file system, virus, or infected USB drives can reach the system’s hard disk. Executing a specific program can activate a virus program. Once the virus program is active, it will infect other computer programs or computers on the network.
Worms
Worms are also malicious code, just like viruses. Worms replicate by separately exploiting vulnerabilities in networks. This generally slows down the networks. The worms run independently. The worm only requires the participation of the user for initial infection, then it works independently.
Once a worm affects a host, it spreads very quickly over the network. Worms share the same patterns. They all have an activating vulnerability, a way to spread themselves, and a payload.
Worms are responsible for some of the most devastating attacks on the Internet. For example, in 2001, the Code The red worm infected 658 servers. Within 19 hours, the worm infected over 300,000 servers.
Trojan horse
A Trojan horse is another malware program that carries out malicious operations under the appearance of a preferred operation, such as playing an online game. This malicious code exploits user privileges that run on the system. A Trojan horse binds itself to non-executable files such as images, audio, video, and games.
Logic Bombs
A logic bomb is malicious software that uses a trigger to activate the malicious code in the operating system. Different types of triggers exist, such as dates, times, other programs running, or deleting a user account. The logic bomb remains inactive until a trigger event occurs.
Once the logic bomb is activated, it performs different functions, such as corrupting or altering data, reformatting a hard drive, and deleting important files. Specialists recently discovered logic bombs that destroy the hardware mechanism in a computer, including the cooling fans, CPU, memory, hard drives, and power supplies.
Ransomware
Ransomware restricts access to the user’s computer and files. It is a type of malware that displays a message and demands payment to remove the restriction from computers and files. It usually encrypts data in the computer with a key unknown to the user. The user must pay criminals to remove the restriction.
Some versions of ransomware use system vulnerabilities to lock down the system. The most common type of ransomware infection is an email containing a malicious attachment or a pop-up advertisement. Some ransomware propagates as a Trojan horse. Once the victim pays, the criminal sends a program that decrypts the data and files or sends an unlock code.
Backdoors and Rootkits
A backdoor is a method of accessing a computer without going through the normal access process, such as entering a name and password. It bypasses the normal authentication used to access a system. The Netbus and Back Orifice are examples of backdoor programs that allow unauthorized system users to access remotely.
The backdoor grants future access to cyber criminals even if the association fixes the original vulnerability used to attack the system. Generally, criminals have authorized users to innocently run a Trojan horse program on their machine to install the backdoor.
A rootkit is used to mask program files to help hackers avoid detection. It is also used to open a backdoor, allowing hackers to access a system without authentication remotely. Usually, rootkits use software vulnerabilities to perform privilege escalation and modify system files.
Rootkits modify system forensics and monitoring tools, making them very hard to detect. Generally, a user should wipe and reinstall the operating system of the infected computer with the rootkit. An example of a virus that installs a backdoor is Mydoom. It creates junk mail and sends it from infected computers.
Defending Against Malware and Malicious Software
There are a few steps to defend you against all forms of malware:
- Antivirus Program –Most antivirus programs catch many forms of malware. However, criminals develop and set up new threats daily. Thus, keeping antivirus signatures updated is the key to a successful solution.
- Up-to-date Software –Many types of malware reach their goal by exploiting operating system and application software vulnerabilities. Earlier, operating system vulnerabilities were the primary source of problems, but now, application-level vulnerabilities create the most significant risk. Operating system vendors are more responsive to patching and updating the system, but Unfortunately, most application vendors are not aware of application vulnerabilities.
