How to Prevent Malware-Free Attacks: Living-off-the-Land Protection Strategies

More than three-quarters of cybersecurity leaders say ransomware is their top concern; with more than 450,000 new malware variants identified daily, the relentless challenge of preventing ransomware attacks is undeniable. But if that weren’t enough, a closer look at the shifting threat landscape suggests malware-free attacks present a rapidly growing risk. Malware-free attacks accounted for 79% of detected threats in 2024, according to CrowdStrike’s latest Global Threat Report – up from 40% in 2019.  

Also known as “living-off-the-land” or “fileless” attacks, these threats are particularly dangerous – and particularly hard to stop – because they rely on legitimate systems rather than malicious files. To help security teams proactively defend against this new wave of threats, we’ll provide a comprehensive overview of malware-free attacks and share strategies for blocking them in real time.  

What Are Malware-Free Cyberattacks?  

Malware-free attacks, fileless attacks, or living-off-the-land (LotL) attacks are cyber intrusions in which adversaries abuse legitimate tools, systems, files, or applications to compromise a network. In other words, malware-free attacks leverage existing tools and processes in the environment, allowing adversaries to evade detection, move laterally without triggering alerts, and steal data without being spotted.  

How Malware-Free Attacks Work: Common Tactics  

There’s no one way to carry out a malware-free attack – they’re relatively simple to perform, as it’s easier than ever for attackers to weaponize the tools defenders rely on. Still, some of the most common tactics include social engineering campaigns, stolen credentials, and vulnerability exploits, among others.  

Phishing and Other Social Engineering Schemes 

According to Verizon’s 2025 Data Breach Investigations Report, social engineering attacks account for nearly a quarter of external security breaches – phishing remains the most common form of social engineering, accounting for 57% of incidents. Social engineering campaigns are an easy entry point for malware-free attacks; for example, a phishing email with weaponized documents may trick users into enabling an attack.  

Stolen Credentials  

The adage that “hackers don’t break in, they log in” has never been truer – today,  three out of every four attacks rely on valid credentials, and credential abuse reigns supreme as the most common initial access vector. Regardless of whether attackers obtain credentials through an infostealer, social engineering, or any number of other tactics, it only takes one legitimate login to open the door for a malware-free attack.  

Native Tool Abuse  

After gaining initial access, adversaries often rely heavily on system tools like PowerShell and WMI during LotL attacks. Attackers use these trusted tools to execute commands, modify configurations, schedule tasks, and more – all without triggering alerts.  

Vulnerability Exploits 

Zero day exploits have jumped 141% in the last five years, so it’s no secret that hidden vulnerabilities leave organizations exposed. Even after a vulnerability is discovered, delayed patching creates windows of opportunity for adversaries to execute zero day attacks with no known signature.  

Supply Chain Attacks  

By targeting trusted commercial products or even open source tools in supply chain attacks, attackers can inject malicious code into seemingly legitimate applications, tricking users into installing backdoors to their networks. In the first half of 2025, supply chain attacks served as the initial access vector for even more publicly disclosed data breaches than ransomware. 

Real-World Examples of Malware-Free Attacks 

Given the rising popularity of malware-free attacks, there’s no shortage of recent real-world examples to bring this concept into focus. Some well-known instances include:  

• SolarWinds: In this highly publicized hack, state-backed gang APT29 carried out a supply chain attack by injecting a backdoor to SolarWinds’ Orion platform; the platform still appeared legitimate when victims installed the next update, but it gave the attackers an initial foothold. From there, they “lived off the land” for lateral movement and privilege escalation, relying on legitimate credentials and remote access.  
• Lazarus Group Crypto Firm Attacks: Another state-backed group, APT38, targeted a variety of firms in the blockchain technology and cryptocurrency industry, leveraging spearphishing campaigns, stolen credentials, and PowerShell scripts to infiltrate the organizations. 
• Astaroth Banking Trojan: First launched in 2017, these attacks typically begin with a phishing email containing a malicious link or attachment, which uses a native Windows process (such as mshta.exe) to launch an obfuscated JavaScript stub. From there, the JavaScript downloads additional files and injects the Astaroth payload into legitimate Windows processes.   

Cybersecurity Trends: Why Malware-Free Attacks Are Surging  

With malware-free attacks now comprising the bulk of malicious activity, there’s no question that trends across the broader landscape have allowed these threats to proliferate.  

EDR Alone Can’t Stop Living-off-the-Land Attacks 

For years, cybersecurity teams have leaned heavily into detection-based security strategies like EDR while deprioritizing protection. The problem with relying too heavily on reactive approaches is that attackers know how to stay one step ahead. In a Red Team Assessment Report, CISA concluded that over-relying on EDR creates insufficient protection to stop all living-off-the-land attacks. In other words, it’s simply not possible to prevent LotL attacks with EDR alone; when so many teams rely heavily on detection-centric strategies, it’s easy to see how malware-free attacks have risen to prominence.  

Machine Identities Create Security Vulnerabilities  

Machine identities like service accounts – which are notoriously overprivileged and insecure – now make up over 70% of networked identities. Meanwhile, only 2.6% of workload identity permissions are actually used, and 51% of workload identities are completely inactive. Hidden identity security gaps like these create easy gateways for adversaries to exploit in malware-free attacks.  

AI-Enabled Attackers Deliver Smarter Campaigns at Scale  

With AI at their fingertips, hackers are more productive and more effective than ever. For example, it takes scammers about 16 hours to manually craft a convincing phishing email; with the help of AI, attackers can design highly targeted messages in minutes. New research from MIT found that 80% of attacks reviewed leveraged AI for everything from deepfake-driven social engineering to password cracking and more, making it easier than ever for hackers to gain initial access via malware-free attacks.  

Access-as-a-Service Is Booming: Identity Is the New Perimeter 

As Chris Boehm, Field CTO, points out: “Most networks were never designed to handle identity as a segmentation boundary.” Still, the reality is that identity-based attacks are accelerating; that growth is partially driven by a booming access-as-a-service industry. Advertisements for access brokers increased 50% YoY in 2024 as hackers ramped up the use of infostealers to collect valuable data like credentials.  

How to Prevent LotL Attacks: Stopping Malware-Free Tactics  

While malware-free attacks can bypass detection-based tools, they’re not unstoppable. The key is prevention – removing attackers’ ability to move laterally or escalate privileges once they gain access. These hardening strategies can help organizations neutralize living-off-the-land tactics before they turn into unseen disasters.  

Enforce Comprehensive Zero Trust Microsegmentation  

Flat networks make it easy for adversaries to exploit legitimate tools across systems. Microsegmentation eliminates this risk by creating secure perimeters around every asset and enforcing strict, fine-grained communication rules. Instead of relying on manual firewall management, modern platforms automate policy creation and enforcement to scale least privilege access as the network changes, enabling a true Zero Trust architecture.  

Granularly Segment All Identities

Identity is the most exploited pathway in malware-free attacks. Enforcing the same granular approach used to microsegment assets at the identity layer means every account – human or machine – is restricted to pre-approved assets and logon types. This addresses the risk of overprivileged admin and service accounts, rendering stolen credentials virtually useless.  

Apply Fine-Grained Access Policies Based on Network Behavior  

Malware-free attacks thrive in plain sight, but when access policies are finely tuned to normal logon activities, account behaviors, and asset access patterns, any unauthorized lateral movement pathways are blocked by default. By crafting policies based on normal communication patterns for every network asset and identity, security teams can prevent adversaries from exploiting overlooked permissions or misconfigurations.  

Layer Just-in-Time MFA for Privileged Access  

Often, malware-free attacks rely on admin credentials or remote management tools. By applying just-in-time (JIT) MFA at the network layer when privileged access is requested, organizations can further neutralize the threat of compromised credentials. The addition of JIT MFA on top of identity-aware microsegmentation prevents attackers from exploiting privileged ports and protocols like RDP and RPC without hindering operations.

Proactively Block Malware-Free Attacks with Zero Networks  

As cyber adversaries get better at blending in, defenders have to shift strategies: rather than detecting malware-free attacks, block them in real time with Zero Networks.  

Zero’s automated, identity-aware microsegmentation solution combines identity segmentation, automated microsegmentation, and network-layer MFA. Using robust deterministic automation, Zero Networks creates fine-grained, adaptive access controls for every network asset and identity, automatically blocking lateral movement and applying just-in-time MFA to privileged logons.    

This multi-layered approach blocks attackers at every turn, turning malware-free attacks from a stealthy goldmine to an automatic dead end. According to Chris Turek, CIO at Evercore, Zero’s combined capabilities create a “new sphere” of security capabilities: 

Find out how Zero Networks can help your organization protect against malware-free attacks – request a demo.