por There are different levels of difficulty and complexity for a cyber attack. Although the impact of a simple attack cannot be underestimated, a security team must pay special attention to the more sophisticated virusesthat’s why you should know what it is fileless malware.
Next, we will talk about a complex technique that an attacker could use to infect a victim without them realizing it. In this post, we will explain what it is fileless malwarehow it is used and how you can protect yourself from one.
What is fileless malware?
We can define what it is fileless malware like a type of virus that does not need a file to run on the victim’s computer. This is malicious code that is executed every time the infected user turns on their machine, but does not correspond to any file that the user can track.
How does fileless malware work?
A fileless malwarealso called malware no file, uses system tools to execute code. For example, in Windows, the PowerShell console interface that comes installed with the operating system.
Fileless attacks can reach a system in different ways. One of the most used vectors for these types of attacks are infected office files with macro viruses. After opening a Word or Excel document with a malwarethe cyberattacker could access the PowerShell program and execute code remotely on the device.
Once on the computer, the fileless malware will first try set persistence, that is, make it run every time the victim turns on their machine. Then he malware will execute its function, which will usually be related to the theft of financial and confidential data.
What is a macro virus?
Now that you know what it is fileless malware, you may wonder how to detect it and protect yourself from it. Therefore, we will review some concepts that will help you anticipate this attack.
A macro virus, for example, is one of the ways in which these attacks are mainly executed. A macro is a program that is embedded in the Microsoft Office fileswhich executes code in the language scripting Visual Basic and containing file formatting instructions. However, in reality it is a wide open door to execute any type of command on the computer.
When malicious code is inserted into the macro of a document, it is called a macro virus or macro attack. The most advanced macro viruses usually instruct their victims’ computers to connect with C&C servers and receive instructions from the attacker. This way you can also run code in PowerShell and establish persistence without leaving any files on your system.
How to defend against fileless malware?
We have already seen what is fileless malware and what is a macro attack. Now, you may wonder how to detect, avoid, and defend against these attacks.
If, for example, a hacker malicious attacker infiltrated a macro virus into the system and gained access to the PowerShell control to execute malware without having any files on the hard driveHow can we detect it and protect ourselves from this attack?
Taking into account that a virus without files is difficult to detect, the best scenario is one in which the malware It does not enter the system from the beginning. This can be achieved by paying attention to the origin of the files we download, searching avoid a Trojan attack. However, it is also necessary to take into account the following to resolve the damage:
Have a good antivirus that is capable of detecting malicious files in case they enter the system. This will not only protect us from a fileless malwarebut also attacks with ransomware and more. The fileless malware They may be designed to not have any source files on the hard drive. However, while they are working, they may download some type of software malicious, like a keylogger to steal passwords, for example. So, this means that an executable file cannot be found for the malwarebut maybe yes some that download while it works. The damage with this type of malware It can be so deep that you have to format the computer. So keep your backups up to date and, if you discover one of these viruses, change your passwords on a secure device as soon as possible.
How to continue learning?
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