What is Fileless Malware? How to Protect Against Fileless Malware?

Computers have always been vulnerable to malicious software. Like any other cyber threat, it has improved in potency and efficiency over time. Malware that doesn’t create a file is one of the most dangerous types of malware. For the first half of 2020, it has been named the “most prevalent critical-severity cybersecurity threat to endpoints.”

The most dangerous aspect of fileless malware is how it hijacks a user’s machine by hiding in RAM and then using the user’s software and programs against them. In addition to being undetectable by standard means, it has no recognizable code or signature, making it even more dangerous.

In this blog post, we will talk about what is fileless malware, how does fileless malware work and why it’s become a widespread attack method with cybercriminals. We’ll also explain how to protect against fileless malware and keep your data safe. So if you want to stay ahead of the game regarding cybersecurity threats, read on!

What is Fileless Malware?

The term “fileless malware” refers to dangerous software that may penetrate your system without needing a specific file. Not all malware, like viruses, behaves this way. Essentially, malicious actors embed fileless malware into legitimate apps and use them to carry out malicious deeds.

One method by which these assaults function is by inserting harmful code into programs with which your computer already comes equipped. Phishing and other forms of social engineering are valuable tools for this purpose. Once the malicious code has been integrated into a trusted program, it can spread laterally throughout your network in search of additional sensitive data.

In most cases, the motivation behind fileless malware assaults is financial or reputational. Since fileless malware is memory-based and lacks a signature like file-based malware like adware, it can be challenging to eradicate.

Businesses, especially those that operate solely online, have been vulnerable to cybercrime for as long as the internet has been around. The frightening worldwide cost of the cybercrime in 2022 was $6 trillion. As a result, businesses must educate their employees about cyber threats such as malware, phishing, scams, etc.

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Characteristics of Fileless Malware

After knowing what is fileless malware, it is important to discuss its characteristics. Below are some characteristics of fileless malware: 

Example of Recent Fileless Malware Attacks

Fileless malware is a growing threat used by attackers to silently infiltrate systems without leaving any trace of malicious files. These attacks are often difficult to detect and can cause significant damage, making them especially dangerous. 

Example#1

One example of a recent fileless malware attack targeted the U.S. Department of Defense in June 2019. The attack was carried out using spear-phishing emails containing malicious links or attachments sent to unsuspecting victims. Once clicked, the link or attachment would execute a PowerShell script which allowed attackers to gain access to the organization’s networks and then install backdoors that enabled further attacks against other systems and data theft. 

Example#2

The second example of fileless malware was discovered in early 2020 as part of the IcedID banking trojan campaign. In this attack, attackers used a combination of phishing emails and malicious links to deliver the fileless payload. Once clicked, the malicious link would download an executable that would inject code into memory and execute it without writing files on the disk.