What is file integrity monitoring?
File integrity monitoring (FIM) is a set of security practices that continuously verify the authenticity of file systems, operating system components, applications, and databases. It compares critical files to a trusted baseline to detect tampering, corruption, or suspicious modifications.
FIM works reactively, using forensics, or proactively, using a set of predefined rules. Organizations implement file integrity monitoring to:
Detect the unauthorized modification of sensitive files and other critical business data
Prevent security breaches and data loss
Trigger real-time alerts
Facilitate forensic analysis
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Why do you need file integrity monitoring?
With cyberattacks on the rise, it's essential to keep an eye on your most essential files and business data. FIM continuously monitors for unauthorized changes, like an account attempting to modify passwords. It flags suspicious activity early to prevent bigger problems from brewing.
| Value/Outcome | Description |
|---|---|
| Discover breaches sooner | FIM continuously monitors the integrity of your most essential system files, including password databases (e.g., /etc/shadow) that attackers might target to gain unauthorized access. Any unauthorized changes, such as unexpected modifications or suspicious code insertions, trigger immediate alerts for investigation. |
| Faster threat response | It’s not enough to know about a breach if you’re powerless to stop it. By identifying early signs of tampering, FIM lets your team act quickly to mitigate the situation. With a clear picture of what files were changed and when, FIM provides actionable insights to speed up your threat investigation and response efforts. |
| Expose security gaps | Beyond revealing malicious attacks, FIM can expose weaknesses in your IT infrastructure by identifying unauthorized or unintentional changes to critical system configurations that could leave your environment vulnerable. By identifying these weaknesses, FIM helps you proactively prioritize security improvements and harden your defenses before they can be exploited. |
| Simplify compliance | Regulations like PCI-DSS (for credit card data) and HIPAA (for healthcare data) demand strict controls to protect sensitive information. Compliance audits often involve reviewing logs and demonstrating control procedures. FIM continuously monitors the integrity of these files, ensuring they haven't been tampered with and facilitating the collection of evidence for compliance audits. |
How does FIM maintain data integrity?
Data serves as the core of most business activities today. From development to payroll to customer relations, data is the lifeblood of your organization. And that makes data integrity central to keeping your business running.
FIM tools let you implement processes to ensure that the data your business relies on reflects a trustworthy picture of reality.
Beyond making your data safer and more usable, file integrity monitoring can bring other benefits. Unauthorized file changes are often the first indication businesses receive of data breaches and ransomware attacks. This means that FIM, especially when integrated with other security solutions, is a great way to shrink your effective attack surface, ensuring:
Business continuity
Simplified regulatory compliance
Early detection of and response to suspicious activity
Which files should you monitor?
While it may seem ideal to monitor every single file your business uses, that would create too much overhead and trigger too many false positives—sending your team to chase down “suspicious” changes (that are probably benign) to non-essential files.
Most organizations implementing FIM find it most helpful to track operating system (OS) files, database files, application software files, archived logs and reports, and any other critical business files.
Note: FIM should ideally be integrated with your other security products. This provides visibility into your entire environment so that your team has enough information at their fingertips to easily determine how meaningful, critical, and actionable any given notification might be.
How does file integrity monitoring work?
Here’s how file integrity monitoring (sometimes also known as file integrity management) works.
As soon as you roll it out…
Within the FIM tool, define the policies, files, and locations that you wish to track, and the software will establish a baseline hash of critical files. While some tools do this using an agent, an agentless solution may be preferable since it is simpler to roll out.
Once in place…
The FIM solution regularly monitors file activity, recalculating file hashes and comparing them to the baseline to determine if anything has changed. It does this by examining one or more of the following criteria:
Cryptographic hashes
File attributes (file extension, size, version, creation, modification date, and other metadata) and last user ID
Digital signatures
If the FIM solution discovers a discrepancy…
It will deliver a real-time notification to your IT and/or security teams. To ensure these alerts are relevant and actionable, it’s best if the FIM solution is integrated with other security tools. The FIM tool also provides essential data in situations of mandatory reporting for regulatory compliance purposes.
What are some obstacles to FIM?
File integrity monitoring plays a major role in any organization’s security preparedness. It constitutes a front line of defense, flagging files the moment they’re changed so that teams can immediately begin remediating any critical issues. Yet there are also a few challenges to keep in mind.
Storage space: FIM solutions have heavy database storage requirements, given that they must store information about file baselines and changes and are constantly comparing files to this stored baseline. This can consume a lot of storage space, especially for large systems—a potential problem that can be mitigated somewhat by selecting only the most mission-critical assets to monitor.
Excess alerts: As with any security tool, FIM can trigger false positive alerts for legitimate changes, especially during system updates or maintenance activities. It's important to understand your system and configure the FIM solution to minimize false positives. Integrating FIM with other security solutions will give teams better visibility into incidents as they occur.
Maintenance: You need to have the resources, including funding and team members, to effectively implement and maintain your FIM solution. This will include conducting regular updates and establishing procedures to act on alerts when necessary.
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What should you look for in a file integrity monitoring solution?
With so many security platforms and tools on the market, make sure to focus on what you need in an FIM solution. Here are a few guidelines to help you make the choice.
| Feature | Capability |
|---|---|
| Agentless monitoring | Traditional tools use agents for FIM. This approach can be challenging to maintain in large, dynamic cloud environments. Modern tools offer you the option of agentless file integrity monitoring. This gives you near-complete monitoring of important file changes without having to maintain agents or external scanners; you also get the flexibility to deploy agents if and where you prefer. |
| Exclusion rules | Cutting through the noise is essential since security teams are inundated by alerts—over 1,000 a day for larger enterprises. Exclusions help avoid unnecessary alerts via configuration settings to disregard changes to certain files or folders, like temporary files or logs that frequently change. Another valuable feature is tag-based monitoring, which lets you easily focus on specific categories of assets. |
| Automated detection | Automating security is of the utmost importance. It will save time by continuously scanning for changes, freeing teams from manual processes so they can focus on higher-priority tasks. |
| Deep visibility | Your FIM solution requires deep visibility, detecting even subtle modifications within encrypted files. The best way to accomplish this is probably an agentless tool integrated within an overall security solution, such as a cloud-native application protection platform (CNAPP). |
| Validation process | Your file integrity monitoring tool must have the ability to ensure data accuracy by comparing critical files to a known good state; this ensures that you can count on your business data at all times. |
| Compliance support | Since maintaining data integrity is often a core requirement of compliance frameworks such as GDPRhttps://www.wiz.io/academy/cloud-compliance-fast-track-guide , your FIM tool should make this task easier with detailed audit trails of file modifications for simplified reporting. |
| Scalability and integration | Finally, as with every other IT and security investment, your FIM tool needs to be able to adapt and scale as your data needs grow and change. Of course, it also needs to work seamlessly with your other security tools for comprehensive coverage so that nothing falls through the cracks. And the best way to achieve this is with a CNAPP tool that features built-in FIM. |
A more proactive approach to FIM
File integrity monitoring is vital for any organization with sensitive data—that is, every modern business. As a CNAPP solution that integrates FIM, Wiz gives you proactive monitoring to safeguard all your systems and critical business information.
Wiz detects unauthorized changes by:
Periodically scanning and comparing files to previous scans
Creating detailed FIM events for any file creation, deletion, or modification
Automating and configuring processes, including tag-based monitoring to cut through the noise and intelligent prioritization of specific resources
Tracking the integrity of system files to protect you against threats like rootkits that often tamper with system files, lingering for weeks or even months while concealing their nefarious activity
Comparing file hashes to a known good baseline, flagging such modifications as early as possible
Plus, Wiz rolls out FIM capabilities completely agentlessly, eliminating the need for extra software on the devices you’re monitoring.
Wiz takes a proactive approach to security risk, eliminating tool overload and alert fatigue while empowering your security teams to automate and prioritize security across your cloud environment.
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