Measuring the Effectiveness of File Integrity Monitoring Tools

A security incident can be the result of a single unauthorised change. A few may say, ‘one change is inconsequential, don’t sweat the small stuff.’ But when it comes to infrastructure security, the detail is of paramount importance! Just a single edit to a single line item can have a negative effect on an entire file or operating system. It’s essential to be made aware of any unauthorised file change and to be made aware with haste. And whilst some may opt for an all-in-one security tool to meet this requirement, the best approach is to rollout a dedicated File Integrity Monitoring (FIM) solution.

Understanding File Integrity Monitoring

FIM tools provide peace of mind that files haven’t been tampered with. When IT teams deploy a new system or component to their infrastructure, they check that the element is configured correctly. Once they have done so, the FIM solution captures the correct configuration and establish a configuration baseline. Administrators can then use this baseline to detect discrepancies in subsequent configurations and alert IT, who can then investigate whether the system’s integrity has been compromised. 

Factors Influencing Effectiveness 

The thing to remember is that all FIM tools are not created equal. There are several factors that contribute to a solution’s overall effectiveness so before settling on the one in front of you, consider whether they have the following capabilities: 

• Comprehensive Baselining – The ability to compare baselines to modified files, preferably on a dashboard showing the files side-by-side, saves a lot of time and effort. 
• Real-time Detection – FIM solutions must detect and alert security teams to changes as quickly as possible to drive down mean-time-to-recovery. 
• Change Analysis and Prioritisation – The ability to analyse and prioritise changes based on file sensitivity and the risk they pose to your business means a tool can be tailored to your needs and goals. 
• Authorised Versus Unauthorised Change Reconciliation – Lack of awareness to a change is a big issue, but then so is an influx of false positive alerts. Your chosen solution must be able to distinguish between authorised and unauthorised changes. 
• Compliance Checking – FIM solutions must be able to determine if a change took systems out of compliance. 
• Detailed Reporting – The solution must provide detailed information about changes and assist in remediation efforts. 

IT teams should also be able to specify which devices and files are critical and which aren’t. For example, a critical file, such as the configuration file of a database, populated with sensitive customer data, would warrant an immediate, high-level response. However, a configuration change to a non-critical system would merely warrant a “best effort” response.  

Finally, it’s important to remember that a FIM solution needs a skilled cybersecurity team to be effective. Here’s why: 

• Deployment and Configuration – Skilled professionals possess the expertise to properly deploy and configure FIM solutions according to specific needs and security requirements. They can customise policies, alerts, and monitoring parameters which will then align with your organisation’s IT infrastructure and compliance mandates, optimising your chosen tool’s effectiveness.
• Policy Management – Cybersecurity professionals can develop and manage FIM policies that accurately define the baseline of authorised files and system configurations. They can fine-tune policies to balance detection accuracy, ensuring that the FIM solution effectively identifies security incidents or integrity violations without overwhelming security teams with irrelevant alerts.
• Monitoring and Analysis – High-level security teams have the knowledge and experience to monitor FIM alerts and analyse detected deviations from the baseline in real time. They can prioritise and investigate alerts, identify potential security incidents or threats, and respond promptly to mitigate risks and minimise the impact on the organisation’s operations and data assets.
• Threat Intelligence Integration – Cybersecurity professionals can integrate FIM solutions with threat intelligence feeds to enhance threat detection capabilities. They can leverage threat intelligence to correlate FIM alerts with known indicators of compromise (IOCs) and emerging cyber threats, enabling proactive threat hunting and response actions.
• Incident Response and Forensic Analysis— If the FIM solution detects a security or integrity violation, skilled professionals can conduct thorough incident response and forensic analysis. They can investigate the incident’s root cause, assess the extent of the compromise, and implement remediation measures to restore systems to a secure state and prevent future incidents.

Metrics for Evaluation

To evaluate the effectiveness of your FIM solution, consider the following metrics: 

• Detection Accuracy—Does your FIM solution accurately identify and alert security teams to unauthorised changes, modifications, or tampering attempts to key files and system configurations? High detection accuracy minimises false positives and alert fatigue. 
• Speed of Response – Does your FIM tool provide comprehensive contextual data and a user-friendly dashboard to help your security teams investigate and respond to incidents quickly? 
• Usability – Managing a FIM solution can be complicated, so your FIM solution should be highly usable. Think about how easy it is to compare configurations, access historical data, and generate reports to evaluate the efficacy of your solution. 
• Flexibility – All businesses are subject to change, and your FIM solution must reflect that. Suppose you merge with another company; your solution must be able to scale up or down to accommodate them easily. Can it?
• Cost-effectiveness – Work out your FIM solution’s return on investment (ROI). How does the cost of implementing and maintaining your FIM solution compare with the value it provides your business? 

Use Cases 

Here are a few FIM use cases: 

• Financial Security – A FIM solution ensures regulatory compliance by monitoring sensitive parts of an infrastructure to meet SWIFT and PCI DSS standards.
• Healthcare Compliance – In healthcare, a FIM solution safeguards critical system files, detecting unauthorized changes to mitigate malware risks and system vulnerabilities.
• Insider Threat Detection – FIM helps tech firms detect insider threats by monitoring file access, alerting on unauthorised modifications, and preventing data exfiltration attempts.
• Cloud Security – A retail corporation may secure its cloud infrastructure with FIM, monitoring configuration changes and application binaries on platforms like AWS and Azure to reduce cloud-related security risks.
• Industrial Protection – FIM safeguards industrial control systems at manufacturing facilities, detecting unauthorised changes to firmware and software configurations to ensure the reliability and safety of critical processes.

Recommendations

To get the most out of your FIM solution, you must continuously evaluate and optimise FIM policies, alerts, and configurations to improve accuracy and relevance while minimising false positives.

Similarly, if you choose to forgo a managed solution, it’s worth providing staff with cybersecurity training and building internal expertise to ensure they deploy, configure, and manage FIM solutions correctly. 

Integrating your FIM with threat intelligence feeds, endpoint detection and response (EDR) solutions, security information and event management (SIEM) tools, and other security resources can also enhance your solution. 

To maximize your ROI, it’s also worth considering what you’ll use FIM for. If you’ve got an audit coming up, you may only want a FIM solution to cover any gaps. 

To find out more about what Tripwire’s FIM solution can do for you, request a demo here.