Demystifying Fileless Malware in Less than 3 Minutes
- by Brittany Day

Malware is by no means a new threat; however, like the majority of digital attacks, malware attacks are rapidly evolving - becoming highly sophisticated, difficult to detect and devastating for victims. An especially dangerous type of malware - fileless malware - is gaining popularity among cyber criminals due to its ability to evade detection and deceive users.
Fileless malware attacks exploit existing, trusted system applications to install and run malicious code on target systems. This malicious code is used to encrypt and exfiltrate sensitive data and transfer this data directly into the hands of the attacker. Fileless malware can be seen as a cyber crime double play - it also enables malicious actors to silently eavesdrop on your system, often providing access to confidential business information.
Because fileless malware does not leverage executable files and, therefore, does not have a signature, the majority of traditional, signature-based antivirus and email security solutions are unable to detect this emerging exploit, leaving users, systems and critical data vulnerable. This article will demystify fileless malware and offer advice on how to safeguard against it - in less than three minutes!
What Is Fileless Malware and How Do These Attacks Work?
Like all malware, fileless malware is typically delivered to victims in a phishing email containing a malicious link to a fraudulent website. When the user clicks on this link, the website loads a program such as Flash or Java that leverages known vulnerabilities to trigger an exploit in a known and trusted application.
Unlike file-based malware, fileless malware does not rely on traditional executable files, called the “payload.” Instead, these advanced attacks employ a technique known as “living-off-the-land”, where attackers use existing legitimate, trusted tools - or LOLBins - for malicious purposes. In this case, threat actors exploit tools built into operating systems such as Microsoft Office Macros, WMI and PowerShell - essentially turning these systems against themselves.
Fileless malware attacks can be used to perform a wide array of malicious activities including the encryption, exfiltration and delivery of critical data to cyber criminals and the compromise of other systems through the installation of malicious code.
As you now know, fileless malware does not involve executable files as regular malware does, making antivirus protection ineffective against these attacks. Instead, fileless malware attacks leave no typical footprint on the target system, and because they use trusted system tools which can’t be removed or disabled, these exploited tools remain running on the system until they’re either told to stop by their operators or they eventually render the system inoperable.
A Few Key Stats:
- Ponemon Institute reports that fileless attacks are 10 times more successful than file-based attacks.
- A survey conducted by Ponemon Institute indicates that there was an alarming 94% rise in fileless malware attacks during the first half of 2018 - and further research reveals that this frightening trend persists.
- In 2018, the notorious SamSam fileless ransomware variant targeted 67 organizations, mainly in the healthcare sector. One Indiana hospital paid the malicious hackers roughly $50,000 to unlock their encrypted data.
How To Defend Against Fileless Malware Attacks
- Conduct regular security hygiene checks to look for vulnerabilities.
- Keep your OS and applications patched and updated.
- Most importantly: implement a multi-layered, threat-ready cloud email security solution capable of detecting and blocking fileless malware emails and other emerging attacks by employing advanced techniques like behavior monitoring, Artificial Intelligence and Machine Learning to analyze every attribute of each email delivered in real-time, preventing all malicious mail from reaching the inbox.
The Bottom Line
Malware attacks are becoming more advanced and effective, leveraging stealthy techniques and evading detection by only running in the computer’s memory as opposed to relying on executable files. Fileless malware attacks are used to gain administrative privileges to systems, download more malicious payloads and perform a wide range of other malicious activities.
Modern threats demand modern defenses, and traditional antivirus and anti-malware software are no longer able to keep pace with today’s exploits. Luckily, by implementing an advanced, adaptive cloud email security solution, businesses can prevent fileless malware emails and other malicious threats from reaching the inbox - safeguarding their most critical assets and their brand.
Blog Articles
-
2021
- Thinking Strategically about Email Security in 2021 and Beyond
- There’s a Lot to be Gained with Effective Email Security
- Behind the Shield: EnGarde Cloud Email Security Explained
- Open Source: A Powerful, Yet Underutilized Weapon against Phishing & Zero-Day Attacks
- Buyer's Guide: What to Prioritize in an Email Security Solution
-
2020
- Effectively Securing Business Email Accounts: Are Employees the Weakest Link?
- Encryption: An Essential Yet Highly Controversial Component of Digital Security
- Business Email Security Redefined: Key Benefits of Securing Your Business Email with Guardian Digital
- 8 Business Email Security Best Practices
- Demystifying Email Encryption: Stop Sender Fraud
- Demystifying Phishing Attacks: How to Protect Yourself Now
- Demystifying Tax Fraud: How to Avoid Falling Victim to Deceptive, Costly Scams This Tax Season
- Coronavirus Phishing Scams are On the Rise - Is Your Business Email at Risk of Infection?
- Dave Wreski: Founder of Guardian Digital – Open Source Cloud Email Security
- New Ransomware Warnings: Is Your Business Safe from This Silent Threat?
- FBI: Existing Cloud Email Protection Inadequate Against Phishing, Ransomware
- Email Risk is Universal: Securing Business Email in Every Industry Sector
- How To Safely Navigate Office 365 While Working Remotely
- Tips and Advice for Staying Safe Online During COVID-19
- Why Your Business Needs Better Email Security
- Defending Against COVID Email Spoofing Attacks with DMARC
- You’ve Got Mail: How To Tell If It’s Fraud
- Open-Source Security Is Opening Eyes
- Think Like A Criminal: How To Write A Phishing Email
- The Four Biggest Email Threats Your Business Faces Today
- Everything On DocuSign Phishing Attacks in 3 Minutes
- Understanding Payload-Less Email Attacks in Under 3 Minutes
- Demystifying Fileless Malware in Less than 3 Minutes
- How to Protect Sensitive Data & Maintain Client Trust in Financial Services Industry
- Exchange Servers Are Vulnerable - Learn How To Secure Your Email Server Now
- Apache SpamAssassin Leads A Growing List of Open-Source Projects Taking Steps to Correct Instances of Racism and White Privilege
- Cyber Risk Is Greater than Ever in the Legal Industry
- Understanding Malicious URL Protection - And Why You Need It to Secure Your Email
- Email Security for SMBs Beyond COVID-19
- Email Risk Is BIG for SMBs - How To Protect Your Business Now
- Email Threats By The Numbers: How Big Is My Risk?
- The Modern Email Threat Landscape: Where Traditional Defenses Fall Short
- Why Email Security Is More Important Than Ever in This 'New Reality'
- The Threat of CEO Fraud Extends Beyond the C-Suite
- Top Email Security Trends Putting Your Business at Risk of Attack
- Think Like A Criminal: What You Need to Know About Social Engineering Attacks in 2020
- Managed Services: A Key Element of Effective Email Security that Even Modern Solutions Lack
- How to maintain security when employees work remotely: Advice from Leading Security Experts
- FBI: The 2020 Presidential Election Is Under Attack by Email Scammers
- AT&T Security Researchers Identify a Correlation between Strong Cybersecurity and Business Success
- The Aftermath of a Cyberattack Pt. 1: Phishing Recovery Basics
- It Pays to be Prepared! Ransomware Preparedness & Recovery Basics
- Breaking Down Fileless Malware: Anatomy of an Attack
- Office 365 Email Is Vulnerable to Attack Without These Critical Supplementary Defenses in Place
- Keep the Holidays Merry & Bright - Beware of These Sneaky Seasonal Phishing Scams
- Migrating Business Email: The Hidden Complexities You Need To Know
- How Do SPF, DMARC & DKIM Secure Email Against Sender Fraud?
- Top Email Security Risks Heading into 2021 - How To Set Your Business Up for Safety & Success
-
2019
- Your Current Approach to Email Security May Not Be Enough
- Ways to Prevent Email Account being compromised in a Breach
- Celebrating 20 Years of Revolutionizing Digital Security
- IBM Closes its $34 Billion Acquisition of Red Hat
- Interview with Security Expert and Author Ira Winkler
- What is Phishing Email? How to prevent Phishing email scams?
- Ways Our Business Email Exceed Your Expectations
- Spear Phishing Protection - Definition & How To Recognize Spear Phishing Email
- What is Whaling (Whaling Phishing)? & How to Prevent Whaling attacks?
- Ransomware Attack Explained - Best Practices For Ransomware Protection
- Business Email Compromise (BEC) - Definition & Prevention From BEC Attacks
- Wire Transfer Scams Involving Real Estate Transactions: How to Prevent Fraud with Effective Email Security
- Guardian Digital and Mautic: A Dynamic Open-Source Duo
- Email Malware - How to Recognize & Prevent Malware Email Attack
- An Open-Source Success Story: Apache SpamAssassin Celebrates 18 Years of Effectively Combating Spam Email
- What is Spam Email - Types & How to Prevent Spam Emails?
- 2020: A New Decade of Digital Threats - Is Your Business Email Secure?
- Linux: An OS Capable of Effectively Meeting the US Government’s Security Needs Heading into 2020
- Complete Guide on Email Security & Threats Faced by Organizations
- Email Virus - Complete Guide to Email Viruses Plus Best Practices
- What Are Zero-Day Attacks & How Can I Prevent Them?
-
2018
- Guardian Digital Keeps its Customers Protected from Intel Design Flaw
- Security Spotlight: Open Source Email Security Solutions
- Top Six Advantages of Open Source Development/Products
- Python and Bash - Contenders for the most used scripting language
- Guardian Digital Outlines Top 4 Benefits of Choosing Cloud
- Unrivaled Protection Against Today’s Most Dangerous Threats
- Guard Your Email Accounts Against Today’s Most Dangerous Threats
- Security Highlights from Defcon 26
- Linux / Open Source FAQs: Common Myths / Misconceptions
- Email Security FAQs Answered by Guardian Digital
- Guardian Digital Mail Systems: Designed to be Secure Without Fail