How ransomware attacks actually start

When most business leaders hear the word “ransomware,” they picture a sudden catastrophe with files encrypted, systems frozen, and a ransom note demanding payment. In reality, ransomware doesn’t appear out of thin air. It unfolds slowly and carefully, often beginning with a tiny mistake or vulnerability that allows attackers in. Understanding how ransomware attacks start is critical to preventing it before it becomes an emergency. 

The quiet beginning: initial access 

The first step in nearly every ransomware attack is gaining a foothold. Attackers use several common techniques to get that first entry point: 

• Phishing emails: Deceptive messages that trick users into clicking a link or opening an attachment that contains malware or a credential-harvesting form.  
• Compromised credentials: Usernames and passwords obtained from other breaches or weak password practices that allow attackers to log in directly.  
• Exploiting vulnerabilities: Attackers scan for unpatched software, remote desktop services, or exposed services to slip through defenses unnoticed.  

This initial access phase is often the least difficult for attackers, because it depends on human error or unpatched systems, both common weak points in many organizations. 

Persistence and stealth: establishing traction 

Once inside, attackers rarely trigger the ransomware immediately. Instead, they work to stay under the radar: 

• Malware may install backdoors or remote access tools. 
• It may connect to an attacker’s command-and-control infrastructure to receive instructions. 
• Threat actors map the network to find high-value targets and credentials. 

This stage is critical, because it allows the attacker to expand their reach without detection. They often move slowly, sometimes remaining undetected for weeks. 

Lateral movement: hunting for more access 

With persistence established, attackers begin what’s called “lateral movement,” traveling from the initially compromised system to others across the network. Rather than immediately encrypting data on a single machine, they seek broader control. This helps them: 

• access servers and shared resources, 
• harvest additional credentials, and 
• gain administrative privileges. 

Lateral movement is a defining characteristic of ransomware chains, and successful navigation through a network can dramatically increase the attacker’s leverage. 

Data exfiltration and encryption prep 

Modern ransomware attacks often include a preliminary step before encryption called data exfiltration. Attackers identify valuable data such as financial records, customer information, intellectual property, etc. and quietly copy it to external servers. This sets the stage for double extortion, where victims are pressured not only to restore encrypted files but also to prevent public release of stolen data. 

Only after these investigations and exfiltration efforts are complete do attackers trigger the encryption phase. 

Attack detonation: encryption and ransom demand 

At this point, the ransomware payload executes across the environment. Files on local machines and network shares are encrypted, rendering them inaccessible. Victims are met with ransom notes that provide instructions for payment (which typically is in cryptocurrency), with looming deadlines and threats of public data release. 

The damage is now visible, but the earlier stealthy phases are what enabled the attackers to reach this point. 

Why understanding the attack chain matters 

Knowing that ransomware is a multi-stage process allows businesses to stop attacks early. The best defenses target the earliest stages: 

• training employees to spot phishing attempts;
• enforcing strong passwords and multi-factor authentication;
• patching systems promptly; and
• deploying monitoring to detect unusual lateral movement. 

By defending those early entry points, organizations can drastically reduce the chances of ever having to deal with encryption and ransom demands. 

If you aren’t sure if your security network is safe against potential ransomware attacks, please reach out to our cybersecurity experts for a consultation.