What is Fileless Malware Attack? A Comprehensive Guide

Table of Contents

In recent years, the rise of fileless malware has captivated the attention of cybersecurity professionals and organisations alike. With their ability to operate stealthily in memory, fileless attacks have been renowned for their mysterious techniques and their potential to bypass traditional security measures.

Let’s delve into the intriguing world of cyber threats and explore the arena of fileless attacks!

What is a Fileless Malware

A fileless malware attack, also known as a fileless attack or fileless malware attack, is a type of malicious cyber attack that operates without leaving traces of files on the victim’s disk. It aims to exploit vulnerabilities in a system’s operating environment to gain unauthorised access and execute malicious activities. Unlike traditional malware that relies on files to execute and propagate, fileless malware leverages legitimate system tools and processes to carry out its malicious activities, making it difficult to detect and mitigate.

The primary characteristic of a fileless malware attack is its ability to reside solely in the computer’s memory, without writing any files to the disk. These attacks typically involve the use of scripts or command-line tools for code execution. By utilising existing system utilities or scripting languages like PowerShell, the attacker can execute malicious code directly in memory, evading traditional file-based antivirus software.

The Ponemon Institute has estimated that the success rate of fileless attacks is approximately 10 times higher compared to file-based attacks. This highlights the rising significance of fileless malware as a prominent threat in the cybersecurity landscape. It is crucial for organisations to adopt necessary security solutions specifically designed to detect and mitigate these evolving threats.

Top Fileless malware examples

The top 5 examples are as follows-

  1. PowerShell Empire: A post-exploitation framework that uses PowerShell for fileless attacks.
  2. Kovter: Spreads through email attachments and exploit kits, employing fileless techniques for click-fraud activity.
  3. Poweliks: Known for their persistence through registry keys and fileless execution.
  4. Emotet: Initially file-based, Emotet has evolved to include fileless techniques, using macros and PowerShell to infect systems.
  5. Dridex: A banking Trojan that has adopted fileless methods, leveraging macros and PowerShell for infection and data theft.

What is the difference between file-based and fileless malware?

  • File based malware relies on executable files that are stored on disk, while fileless malware operates in memory without leaving persistent files, making it harder to detect and remove.
  • File based malware typically utilises executable files, while fileless malware exploits trusted processes and scripts.
  • File based malware can be automated through the execution of malicious files, while fileless malware leverages existing system components to carry out its malicious activities.

What is the origin of fileless malware?

The origin of fileless malware can be traced back to advancements in cybersecurity technologies and the evolving tactics employed by cybercriminals. As traditional security measures improved in detecting and blocking file-based malware, attackers began exploiting legitimate processes, scripts, and memory-based techniques to carry out their malicious moves without relying on persistent files.

Don’t let fileless attacks compromise your business. Reach out to us for a tailored security solution that combines advanced threat intelligence, and proactive monitoring to keep your systems secure!

How does a fileless malware work?

Fileless malware employs a unique technique to carry out its malicious activities, allowing it to evade detection by many security solutions and impede forensic analysis efforts. While not conforming to the traditional concept of a virus, fileless malware operates in a similar fashion by residing solely in a computer’s memory.

Unlike conventional type of malware that relies on files stored on the hard drive or direct installations, fileless infections bypass these avenues entirely. By leveraging low-observable characteristics (LOC) attacks, fileless malware gains access to a system’s memory, ensuring that the malicious content never touches the disk.

One prevalent method utilised by fileless malware involves exploiting the capabilities of Microsoft Windows PowerShell. PowerShell, a legitimate and powerful tool employed by administrators for automation and configuration management, offers adversaries a versatile command-line shell and scripting language, granting them extensive access to various aspects of the Windows operating system. This integration of fileless techniques, combined with social engineering tactics, enables attackers to infiltrate systems without leaving the traces associated with file based malware.

Stay one step ahead of fileless attackers. Contact Us today for a 360 security solution!

What are the stages of a fileless attack?

Fileless attacks follow a series of stages, each with its own techniques and objectives. These stages outlined below demonstrate how fileless attacks can unfold, highlighting the use of various techniques to gain access, maintain persistence, and exfiltrate data.

Stage 1: Initial Access

Technique: Exploiting vulnerabilities or leveraging web scripting for remote access.

In this stage, the attacker gains remote access to the target system, establishing a foothold for the subsequent stages of the attack. Techniques like exploiting vulnerabilities or using web scripting tools, such as China Chopper, enable the attacker to breach the system.

Stage 2: Credential Theft

Technique: Exploiting vulnerabilities or using tools like Mimikatz to steal credentials.

Once inside the system, the attacker focuses on acquiring credentials for the compromised environment. By leveraging the access gained in the previous stage, they aim to obtain usernames, passwords, or other authentication details. These credentials allow the attacker to move laterally within the environment and access additional systems.

Stage 3: Persistence

Technique: Modifying the system’s registry to establish a backdoor.

To maintain a long-term presence within the compromised environment, the attacker modifies the system’s registry. This modification creates a backdoor, ensuring they can re-enter the system easily without repeating the initial stages of the attack. Techniques like the Sticky Keys Bypass may be employed to achieve persistence.

How does filesless malware achieve persistence?

Fileless malware achieves persistence by modifying the system’s registry, creating or modifying scheduled tasks, installing itself as a service, leveraging trusted binaries and scripts, injecting code into memory, and exploiting PowerShell. These techniques allow the malware to maintain a presence within the compromised system without relying on traditional file-based mechanisms, making it harder to detect and remove.

Stage 4: Data Exfiltration

Technique: Utilising the file system and built-in compression utilities, followed by data upload via FTP or other means.

In the final stage, the attacker collects the desired data and prepares it for exfiltration. They may gather the data from various locations using the file system and leverage built-in compression utilities like Compact to compress the data. Once prepared, the attacker removes the data from the victim’s environment by uploading it via FTP or other methods, effectively exfiltrating the stolen information.

By operating solely in memory, fileless attacks can present significant challenges in detection and mitigation, making them a potent threat to target systems.

Invest in advanced security solutions, which utilise behaviour-based detection mechanisms to identify suspicious activities and anomalies associated with file-less attacks.

How to detect fileless malware attacks?

There are several techniques and best practices you can employ to help identify and mitigate fileless malware attacks. Here are some recommendations:

  1. Use modern endpoint protection solutions designed to detect fileless malware.
  2. Monitor process behaviour for unusual activities like code injection or unauthorised network connections.
  3. Perform memory analysis to identify malicious code or payloads in memory.
  4. Monitor network traffic for suspicious patterns or connections to command-and-control infrastructure.
  5. Utilise user behaviour analytics to identify deviations from normal patterns.
  6. Keep systems and software up to date with patches and perform regular vulnerability scanning.
  7. Educate employees about fileless malware and promote cautious online behaviour.
  8. Deploy a Security Information and Event Management (SIEM) solution for event correlation.
  9. Leverage behavioural analysis and machine learning to detect suspicious activities.
  10. Develop and regularly test an incident response plan specific to fileless malware attacks.

How do I know if my computer has malware?

Signs of malware on your computer include slow performance, unexpected pop-ups, unexplained system crashes, excessive network activity, and changes in browser settings or the homepage. Additionally, if you notice unfamiliar programs or files, disabled antivirus software, or unauthorised access to your personal information, it may indicate malware presence.

Reach out to us today for a Free consultation and start your journey towards a more secure future.

How to prevent fileless attacks?

Preventing fileless attacks requires implementing effective security measures. Here are some steps you can take:

  1. Keep your software and operating systems updated to ensure you have the latest security patches.
  2. Deploy robust endpoint protection solutions that include advanced threat detection capabilities.
  3. Educate users about the risks associated with fileless attacks and train them on safe computing practices.
  4. Follow the principle of least privilege, granting users only the necessary access privileges.
  5. Implement application whitelisting to allow only trusted and authorised applications to run.
  6. Implement security measures specific to the PowerShell script, such as restricting execution policies and enabling script logging.
  7. Segment your network to isolate critical systems and limit the impact of potential attacks.
  8. Enable multi-factor authentication (MFA) to add an extra layer of security to user accounts.
  9. Monitor network traffic for anomalies and use intrusion detection systems to detect suspicious behaviour.
  10. Conduct regular security audits and vulnerability assessments to identify and address potential weaknesses.

The Australian Government has also developed a Strategy to position itself as a global leader in cybersecurity by 2030. The Strategy aims to protect Australians by enhancing cybersecurity, managing cyber risks, and supporting citizens and businesses in navigating the cyber landscape. The Strategy envisions a future where robust cyber protections enable prosperity and quick recovery from cyber attacks.

How Binary IT helps to protect against fileless malware attacks

We understand the criticality of protecting your business against fileless malware attacks. That’s why we leverage our expertise in Sydney, your trusted partner in cybersecurity.

By implementing advanced threat detection mechanisms that analyse behaviour, detect anomalies, and identify memory-based attacks, they ensure that fileless malware is swiftly detected and mitigated. Our Managed security services provide round-the-clock monitoring, intrusion detection, and the ability to uncover even the most subtle fileless malware activities. With us by your side, you can rest assured that your organisation is equipped to combat the ever-evolving threats of fileless malware.

Fileless malware is on the rise, but you can fight back. Get in Touch today.

Written By:



Latest Blogs

Send us a Message

More Posts

Report A Cyber Threat

Need help from our investigation and response team?