Fileless malware: Why traditional endpoint security falls short

What is fileless malware?

Fileless malware works entirely in the computer's temporary storage, often using standard administrative tools like PowerShell, Windows Management Instrumentation (WMI), or scheduled tasks to perform malicious activities. Since it does not place files on the hard drive, security systems scanning for file-based threats frequently miss this attack vector.

These fileless threats enter a system typically through exploited software weaknesses or through user manipulation techniques (such as getting targets to open emails that contain harmful scripts, which are deployed once the email is opened). Once activated, they can collect login information, transmit data off the network, configure means to access the system later, or serve as a launchpad for other attacks. The lack of a file signature makes it impossible to locate them, necessitating complex protection systems that analyze behavior, check memory, and monitor script execution in real time.

What makes fileless malware work

A 2023 report by Mandiant —the security consulting part of Google Cloud—emphasized how fileless malware is a common feature in advanced persistent threat (APT) campaigns, often using legitimate system tools like PowerShell, WMI, and PsExec to evade traditional detection methods. Updates from MITRE ATT&CK also highlight the growing use of “living off the land” tactics, which are typical of fileless attacks.

Detecting these attacks is especially challenging. Most organizations only realize an intrusion after the fact, during incident response, when critical volatile data is already gone. Memory has been overwritten, logs have rotated, and attackers have long since disappeared. Staying hidden is their primary objective. There’s no installer, no executable. Instead, the attack slips in through things users will already be interacting with—emails, office documents, links—and abuses the tools already present on the system. It’s not a new exploit, but a different use of what’s already there.

The PowerShell, WMI, and command-line tools were built for flexibility and control, which can be abused if not properly constrained. They’re powerful because they’re trusted. That trust becomes a weakness when attackers start scripting in memory.

No files get dropped. Nothing hits the disk. And when the system reboots, the evidence is gone unless memory dumps were captured during the attack window. Most aren’t. Before that wipe out, however, there is a first move—an entry point that lets the attacker in.

How the attacks usually start

Most fileless attacks still begin with social engineering—phishing emails or poisoned links. Once the attacker gets access, even limited, they run scripts using built-in tools. From there, it escalates.

Here’s what often follows:

• Data access

  Pulling credentials; extracting sensitive information.

• Privilege escalation

  Expanding access by impersonating trusted processes.

• Lateral spread

  Jumping between systems without touching the file system.

• Payload delivery

  Often drops ransomware or spyware late in the cycle.

The real strength of these attacks is their ability to hide in normal operations. There are no clear signals—just a shift in behavior.

This complexity is what makes it difficult for traditional defenses to detect fileless attacks.

Why traditional defenses struggle

Security tools that look for malicious files won’t find anything. Fileless attacks don’t drop payloads—they run commands directly in memory. The activity might look like normal administration unless someone is watching closely.

The methods aren’t new. What’s changed is the consistency and precision with which attackers are using them. Threat groups no longer need novel malware strains when they can write two lines of PowerShell and achieve the same outcome.

A few known campaigns

These are well-documented actors, but copycat operations using the same methods have become more common. Toolkits and playbooks circulate freely in forums, and they’re easy to modify.

Analysts are adjusting their models

Security analysts tracking these trends are shifting their frameworks. The 2024 Magic Quadrant for Endpoint Protection Platforms report highlights a shift away from file-based prevention as a primary criterion. It now emphasizes behavior monitoring, script visibility, and endpoint response as more reliable indicators of potential exposure.

Forrester echoed this progression when covering its Extended Detection And Response Platforms, Q2 2024 report, urging security teams to move beyond checklist-driven evaluations. The report emphasizes continuous, real-world testing—from red teaming to threat simulations—using frameworks like MITRE ATT&CK as the benchmark. Static policies aren’t cutting it anymore.

The answer isn’t more tools—it’s a smarter use of what’s already in place.

Defenses that still work

You don’t need a brand-new product to respond to these threats. You do need to pay attention to activity patterns and restrict unnecessary access to powerful tools. Here’s what still makes a difference:

• Endpoint detection and response (EDR) tools

  They track command execution, child processes, and script behaviors.

• PowerShell restrictions

  Constrained Language Mode can prevent risky commands.

• Access limits

  Don’t give admin rights to users or services that don’t need them.

• Routine patching

  Most successful attacks still hit old, known vulnerabilities.

• Logging and monitoring

  Track PowerShell, WMI, and network traffic with alerting thresholds.

The trick isn’t to look for malware, but to spot when someone’s using a trusted tool in the wrong context. That shift—from scanning files to observing intent—is where ManageEngine Endpoint Central fits in.

What Endpoint Central brings to the table

Endpoint Central wasn’t built around file scanning—it looks at system behavior. That’s what makes it suited for dealing with fileless threats. It doesn’t wait for a signature; it watches what’s happening on the machine.

Here's a look at the features designed to reduce fileless attacks:

• Monitoring memory for active threats

  Fileless malware operates directly in system memory, bypassing disk-based storage to stay undetected. Endpoint Central applies inspection tools to scan RAM for unusual behavior, such as encoded shellcode or payloads injected through reflective DLL techniques. This setup identifies and responds to threats that avoid standard detection paths.

• Advanced detection with deep learning

  The DeepAV Engine in Endpoint Central uses neural networks and machine learning to analyze system behavior patterns instead of relying solely on predefined threat signatures. It examines events like unexpected PowerShell use, misuse of WMI, or unsanctioned script triggers, enabling it to recognize a range of threats—including those that have not yet been cataloged.

• Use of decoy files to identify ransomware.

  Ransomware that uses fileless methods frequently takes use of legitimate technologies to initiate encryption. Endpoint Central installs decoy files throughout the system to detect this behavior. When these files are targeted, the system logs each incident, notifies administrators, and may stop the process or isolate the computer.

• Behavior analysis for anomaly detection

  Endpoint Central creates a profile of typical system and user actions. When deviations occur—such as unexpected registry updates, abnormal process injection, or outgoing traffic surges—they are documented for further investigation. This aids in detecting activities that might otherwise appear harmless due to its reliance on permitted utilities.

• Alignment with MITRE ATT&CK framework

  To add perspective to detected events, Endpoint Central references tactics and techniques from the MITRE ATT&CK framework. Examples include persistence through WMI or execution through PowerShell. This correlation assists in understanding the intent and method behind suspicious behavior.

• Consistent protection across connectivity states

  Endpoint Central continues to monitor devices—both when they are online or offline from the network. Each device runs a local agent, which collects and stores security data. Once reconnected, the data syncs with the central console, updating detection rules and taking any necessary action.

• Reduction of false positives

  Endpoint Central's detection layers combine AI-based behavior tracking, deep learning models, and threat mappings to eliminate unnecessary alerts. This configuration helps IT teams focus attention on events that are more likely to be serious dangers, rather than overwhelming teams with small anomalies.

• Next-generation antivirus capabilities

  The antivirus module in Endpoint Central applies prediction techniques and behavior tracking supported by AI. Instead of only relying on static files for analysis, it watches for unauthorized memory use or abnormal script launches, catching both common and previously unknown threats.

• Continuous behavioral monitoring

  The system watches live system activity, from changes in the registry to ongoing network traffic and process execution. This approach focuses on recognizing signs of misuse that rely on trusted tools, which would otherwise pass unnoticed during a routine file scan.

• Immediate threat response mechanisms

  When unusual behavior is flagged, Endpoint Central can act without delay. It can shut down processes or cut the endpoint off from the network to stop the spread. This quick response limits the time a threat has to do harm across the environment.

• Ransomware mitigation strategies

  Fileless malware can serve as a step in the ransomware attack chain. Endpoint Central looks for signs of this by watching for encryption activity directed at bait files. If detected, the system warns administrators and can trigger processes that stop encryption and protect data.

• Management of vulnerabilities and patches

  Endpoint Central checks systems for known weak points that fileless malware might use. It organizes them by priority and automates patching schedules to close off these paths before they can be taken advantage of.

• Control over applications and user privileges

  By setting limits on which tools are permitted to run and adjusting user permissions, Endpoint Central blocks unauthorized or unknown scripts from executing. This involves allowlisting approved applications and tightening access to system-level features.

• Detection of memory-resident threats

  Some threats run entirely within memory and leave nothing behind on disk. Endpoint Central looks for signs of this in active RAM, such as encoded payloads or scripts executed through .NET. This lets the system identify threats that bypass traditional methods.

• Centralized oversight and incident analysis

  Endpoint Central provides a console that consolidates activity across devices. From here, security teams can view real-time updates, generate reports, and trace incidents to their source. This helps in piecing together how attacks unfold and informs future defensive strategies.

Focused response without additional noise

No system catches everything. But watching for the right signals can give defenders the time they need to shut things down before real damage is done. Endpoint Central brings together multiple layers of defense that target how fileless malware behaves and spreads. From monitoring system memory and analyzing behavior patterns to deploying decoy files and mapping threats to known attack techniques, each part plays a role in identifying and containing activity that slips past traditional security tools.

Endpoint Central's ability to present detailed threat reports through a single console and to maintain consistent oversight—whether devices are online or not—helps teams stay focused on the activity that matters. For organizations facing stealth tactics and living-off-the-land techniques, Endpoint Central provides structure, visibility, and practical tools that support focused response without adding noise.