Modern cyber threats increasingly target sensitive files, configuration directories, and Windows registry settings. Once attackers gain access to these resources, they can encrypt business data, alter system behaviour, or compromise critical infrastructure.
Traditional security controls such as file permissions or antivirus software often struggle to prevent these attacks. Malicious processes can still gain access to important files and begin encrypting or modifying them before they are detected.
To strengthen data integrity and cyber resilience, organisations are increasingly implementing application-based access control that restricts which programs can interact with sensitive data.
FSBlocker from Cristie Software provides this capability by enforcing kernel-level protection for files, folders, and registry keys, helping organisations prevent unauthorised access and reduce the risk of ransomware or system tampering.
The registry is used as a critical tool for attackers to maintain control over a system.
of all resident malware adds itself to “Run” keys so it restarts every time you boot your PC..
of enterprise attacks use scripts or shellcode in “hidden” keys, allowing the virus to run entirely in your computer’s RAM.
FSBlocker is a Windows security solution from Cristie Software that protects files, folders, and registry keys using kernel-level application-based access control. Administrators define policies that permit only authorised applications to read or modify protected data, preventing ransomware, malicious processes, and unauthorised system changes.
By enforcing security policies within the Windows operating system, FSBlocker ensures that sensitive data locations can only be accessed by trusted processes.
Systems are restored into a virtual, isolated Clean Room environment.
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Automated and manual testing is performed to check for system integrity, malware remnants, or misconfigurations.
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Once verified, the systems are migrated back to the production environment, or transitioned into a new clean production state.
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FSBlocker protects Windows systems using several key capabilities:
These controls help organisations safeguard critical data and maintain compliance with security frameworks such as NIST, CIS Benchmarks, ISO 27001, and GDPR.
| Source | Statistic | Insight / Relevance |
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80% of organizations that paid a ransom were hit again
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Ransom payment does not guarantee immunity; many attackers return for more. |
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31% of ransomware victims were hit multiple times in the same year
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Reinfections are common and often happen quickly after the initial incident.
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80% of ransomware victims are likely to suffer repeat attacks |
Reinfection risk remains high without full recovery and threat neutralization. |
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66% of organizations experienced ransomware attacks in 2023 |
Overall attack prevalence is rising; without strong recovery practices, recurrence grows. |
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Repeat attacks often occur within weeks to months after the first breach |
Reinfections typically exploit the same vulnerabilities that weren’t fully resolved. |
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Standard Windows file permissions are designed primarily for user access control, not for preventing malicious applications from interacting with sensitive files.
For example, if a ransomware process executes on a system, it may inherit the same permissions as the logged-in user. This means it can potentially access and encrypt large numbers of files before security software detects the activity.
Similarly, malware may attempt to modify Windows registry keys or system configuration files to establish persistence or disable security tools.
Application-based access control addresses this problem by focusing on which programs are allowed to access protected data, rather than relying solely on user permissions.
By restricting access to approved processes, organisations can prevent unauthorised software from interacting with critical files and configuration data.
Backups that once written cannot be altered in any way.
A security framework based on the principle of “never trust, always verify”.
An integrated security solution that continuously monitors end-user devices to detect, investigate, and automatically respond to advanced cyber threats that traditional antivirus software might miss.
The comprehensive strategy for restoring full IT operations after a major catastrophe.
The following steps outline the key tasks required to configure FSBlocker and protect sensitive data locations.
Step 1 – Configure the FSBlocker Driver
FSBlocker relies on a Windows filesystem filter driver that intercepts file access requests before they reach storage.
To enable this protection:
Once enabled, the driver monitors file access activity and enforces defined security policies.
Administrators should also attach the driver to the drives containing sensitive data.
Examples may include:
Step 2 – Enable Windows Registry Monitoring
Many cyber attacks attempt to modify registry keys in order to change system behaviour or establish persistence.
FSBlocker can monitor and restrict changes to protected registry locations.
To enable this capability:
Once enabled, registry paths can be included in protection policies in the same way as file system paths.
This helps safeguard:
Step 3 – Create a Protection Policy
FSBlocker uses policy-based access control to define which applications can interact with protected files.
To create a policy:
During the first step of the wizard, administrators define:
Example protected location:
C:\SensitiveDocuments
Once created, the policy governs how applications interact with the selected path.
Step 4 – Define Application Access Rules
Next, administrators specify which applications can access the protected data.
FSBlocker supports three rule types:
Access Type | Behaviour |
Allow | Application can read and modify files |
Read-only | Application can view files but cannot modify them |
Block | Application cannot access the path |
Example policy configuration:
Application | Access |
backup_agent.exe | Allow |
explorer.exe | Read-only |
unknown_process.exe | Block |
This approach ensures that only trusted applications can modify sensitive data.
Step 5 – Enable Signature Lock
FSBlocker includes a feature called Signature Lock to verify the authenticity of executable files.
When enabled, FSBlocker validates:
If a process fails validation, access to protected files is denied.
Signature Lock helps prevent attackers from replacing trusted executables with malicious versions.
Step 6 – Monitor File Access Activity
FSBlocker provides real-time visibility into system activity through the Activity dashboard.
Administrators can view:
Monitoring these events helps identify suspicious behaviour and refine security policies.
To maximise the effectiveness of application-based access control, organisations should follow several best practices.
Maintaining well-defined security policies helps ensure that critical files remain protected as systems evolve.
“In 2025–2026, roughly 55% of all Windows vulnerabilities involved “Privilege Escalation.” Attackers frequently use the registry to trick Windows into giving them “System Admin” powers.”
Preventing unauthorised file access is only one component of a broader cyber resilience strategy.
Organisations must also ensure they can recover quickly if a system compromise occurs.
Cristie Software provides a range of technologies designed to support this goal, including solutions for:
Together with FSBlocker’s kernel-level protection, these tools help organisations maintain operational continuity and minimise downtime in the event of cyber incidents.
The most effective way to protect Windows files from ransomware is to restrict which applications can access sensitive data. Security controls such as application-based access policies allow administrators to define which programs are permitted to read or modify protected files. If an unauthorised process attempts to encrypt the data, the action is blocked before it reaches the filesystem.
Protecting the Windows registry requires monitoring and restricting which applications can modify sensitive registry keys. FSBlocker enables administrators to define registry protection policies that allow only trusted processes to change configuration settings, helping prevent malware persistence and unauthorised system changes.
Kernel-level file protection controls access to files within the operating system kernel. By intercepting file access requests before they reach storage, security software can enforce policies that prevent unauthorised applications from modifying sensitive data.
Application-based access control restricts which programs can interact with protected data. Administrators define policies that allow only approved applications to read or modify files, preventing unauthorised processes from accessing sensitive information.
Yes. FSBlocker can monitor and restrict modifications to protected Windows registry locations, helping safeguard system configuration settings and application integrity.
FSBlocker uses a lightweight filesystem filter driver designed to operate efficiently within the Windows kernel, allowing security policies to be enforced with minimal performance impact.
FSBlocker helps organisations protect sensitive data, configuration files, and registry settings using kernel-level application access control. Combined with Cristie’s recovery and replication technologies, it forms a powerful foundation for cyber resilience in modern IT environments.
Learn more about Cristie solutions at www.cristie.com/products/fsblocker.
