Information Technology

The Complete Guide to Fileless Malware

What is Fileless Malware?

Fileless malware is a form of malware that doesn’t need to be installed on the target system. It just needs to be located in a specific file and executed. Fileless malware is a type of malware that doesn’t use files on the computer’s hard drive to infect it. Instead, it uses other methods to spread and infect the system.

The most common ways of fileless malware infection are through network shares, email attachments and USB drives. The most dangerous aspect of this type of malware is that it can’t be detected by traditional antivirus software and anti-malware software because it doesn’t use files on the hard drive to do its dirty work.

How does Fileless Malware Works !

It is important to note that fileless malware does not mean a piece of malware that does not have a file. What it means is that the file is not saved locally on the hard drive. Malware can be executed directly from memory, which means that the malware is not actually installed on the computer it just runs in the memory.

In order to be executed, it must be loaded into the memory by a running process or the operating system itself. This is done by modifying certain Windows registry keys and Windows Management Instrumentation (WMI) event consumers, which is an event provider that allows management applications to receive events, such as the creation of a new process, from the operating system.

The following is a few scenarios in which fileless malware can use your system’s software, applications and protocols to install and execute malicious activities:

  • Phishing emails, malicious downloads, and links that look legitimate as points of entry.
  • Applications you’ve already installed, like Microsoft Word or JavaScript.
  • Native and highly trusted applications like Windows Management Instrumentation (WMI) and Microsoft PowerShell.
  • Lateral infiltration.
  • Legitimate-looking websites that actually are malicious.

Why Attackers Choose Fileless Malware

A fileless malware is a type of malware that uses a different method to spread than traditional malware. It can be very difficult to detect and remove. .But it is still possible to remove. By reviewing and understanding this kind of malware, you can learn how to avoid being infected by this type of malware in the future.

Attackers are increasingly using fileless malware because it allows them to:

  • Remain undetected for longer periods of time since traditional anti-virus software is not effective in detecting fileless attacks.
  • Exploit a vulnerability that will give them administrator access and complete control of a system.
  • Gather data from their target to be used for later attacks.

How to Detect Fileless Malware

Detection of fileless malware is a big challenge for security teams. There are many ways to detect fileless malware, , but there are also many ways to hide it. This is why the current trend for fileless malware detection and removal involves use of various detection methods, such as fully-automated approaches. One of the main problems in this regard is a lack of reliable and portable detection techniques that work in every environment and with all types of malware.

Malware-based attacks are noisy and therefore easier to detect and respond to, and the days where defensive security solutions could easily spot these signature-based threats are behind us. Realizing this, attackers have responded by evolving to techniques that rely on tools that already exist within the environment, abusing insider credentials or using SSL tunnels to legitimate sites for command and control.

Indicators of Attack (IOAs) are a way to take a proactive approach against fileless attacks. IOAs do not focus on the steps of how an attack is being executed instead, they look for signs that an attack may be in progress.

This means that security teams must now detect malicious intent that blends with business-justified activity, a task that is both tedious and challenging for most analysts.

Possible ways to protect an organization against fileless malware:

One of the most common ways to protect an organization against fileless malware is by creating a whitelist of known and trusted files.

This approach has been used by antivirus companies for some time. However, it was found that many untrusted files were still included in the whitelist. This problem can be solved by adding a filter to the whitelist that excludes untrusted files and only allows those that are known to be safe. The filter can be implemented using a Content-ID or IP address as an identifier for each file and then using a whitelist mechanism to determine whether or not a file should be included in the list.

These fileless attacks often rely on human vulnerability, which means user and system behavior analysis and detection will be central to security. Key best practices on an individual level include:

  • Being careful when downloading and installing applications.
  • Keeping up-to-date with security patches and software applications.
  • Updating browsers.
  • Watching out for phishing emails.

CXO's Journal

I'm a self-taught hacker, I do a little bit of everything: hacking (security), cryptography, Linux system administration, networking/routing and virtualization/hardware/software development. I'm a freelance IT Support Advisor, providing IT support to small and medium-sized enterprises (SMEs).
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