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SIEM Migration: Challenges and Strategies

CISOs and SOC teams often find themselves faced with the difficult question of whether or not to migrate from one Security Information and Event Management (SIEM) solution to another. While this transition decision may stem from various factors such as scalability requirements, technology updates, or changes in organizational needs, the journey from one SIEM to another is not without its challenges.

In this exploration, we delve into the intricacies of SIEM migration, focusing on critical aspects like the SIEM style, data acquisition, correlation methods, securing the SIEM, and the imperative task of migrating SIEM detection coverage.

Understanding SIEM Styles

The choice of a SIEM solution significantly influences how an organization approaches security monitoring and incident response. The style of the SIEM encompasses its implementation, ownership, and the specific problems it aims to solve. Here, we dissect some critical elements of SIEM styles:

On-Prem vs. Cloud: The decision to migrate may involve transitioning from an on-premises SIEM to a cloud-hosted service. This shift necessitates considerations about data transmission, security, and adapting to the unique features offered by cloud-based solutions which can provide benefits around scalability and cost-effectiveness.

Raw Log Collection vs. Normalized Logs: Different SIEMs handle log data in distinct ways. Migrating from a SIEM that normalizes logs (e.g., ArcSight, Sumo Logic) to one that retains raw logs (e.g., Splunk, Devo) can pose challenges in reproducing correlation and reporting processes.

Live Correlation vs. Batch Queries: Understanding whether your current SIEM relies on live correlation (e.g., ArcSight, QRadar) or batch queries (e.g., Google Chronicle, Splunk) is crucial. Shifting from one approach to another may impact the way threats are detected and responded to within the organization.

Data Acquisition and Detection Content Dilemmas

Data acquisition is a pivotal aspect of SIEM migration, encompassing the gathering, normalization, and storage of log data. As organizations transition, they must grapple with the following considerations:

Cloud Transition Challenges: Migrating from an on-premises SIEM to a cloud service involves configuring firewalls, ensuring data source compatibility, and addressing potential disparities in the collection capabilities of various data sources.

Parsing and Normalization Pitfalls: The parsing and normalization of log data differ among SIEM solutions. Mismatched parsing methods can lead to discrepancies in log formats, field names, and overall data structure, affecting correlation and reporting.

Scalability Struggles: SIEMs vary in their ability to handle large volumes of log data. Understanding the scalability features of the new SIEM is crucial to avoid data loss during spikes and ensure uninterrupted data flow.

Detection Content: Some SIEM providers will have extensive libraries of detection content and supported parsers, where others will be much more limited. It is important to understand your security team’s access to detection content and ability to create or source this content on their own or if supplementing this with a solution provider is necessary (Note: the CardinalOps platform can recommend and push curated, high-fidelity detections directly to your SIEM that have been pre-validated and auto-customized for your environment). 

Correlation Conundrums

Correlation is the heartbeat of SIEM functionality, and different solutions adopt varied approaches. When migrating, organizations must adapt to the correlation style of the new SIEM:

Live Correlation vs. Batch Queries vs. Statistical Correlation: The transition between live correlation, batch queries, and statistical correlation (often presented as machine learning) introduces distinct challenges. Each approach has its trade-offs in terms of speed, resource utilization, and the type of threats it is best suited to detect.

Ensuring SIEM Security

As organizations migrate from on-premises SIEMs to cloud-based services, ensuring the security of log data becomes paramount. Consider the following security imperatives:

Identity Verification: Establishing secure methods for identifying data sources is essential to prevent the injection of spoofed or malicious data into the SIEM.

Secure Storage and Access Control: Organizations must guarantee the secure storage of log data, employing encryption and robust access controls. Limiting access to configuration settings, both for end users and administrators, enhances overall SIEM security.

User Account Management: Efficient creation, disabling, and management of user accounts, both for end users and administrators, play a pivotal role in maintaining a secure SIEM environment.

SIEM Migration and Detection Content

Effective migration from one SIEM to another will require careful planning and execution to ensure a smooth transition and maximize the benefits of the new platform. A key element to this is prioritizing your detection content.

Analysis of Existing SIEM Detection Content: A comprehensive analysis of the existing SIEM infrastructure is crucial during this process. This analysis not only aids in identifying and reducing potential volumes of detections for migration but also helps pinpoint and rectify broken or redundant rules. It provides valuable insights into the appropriate allocation of work within the team by balancing the complexity of rules with their importance.

Prioritize Detection Content: Evaluate your existing detection content and migrate only the rules and alerts that are necessary for your new environment, avoiding unnecessary complexity. Mapping each rule to relevant log sources is a strategic move, allowing for efficient management of dependencies and priorities: assessing the different security use cases can assist in prioritizing which data sources (and associated rules) should migrate first and where query optimizations can be found to help reduce costs. 

Rebuild Detection Content: Migrating all existing detection content from one SIEM to another can be difficult if not impossible with differences in styles, query languages, and many other factors. Instead, look for equivalency of coverage based on MITRE Technique / Sub-Technique and/or look to recreate it from scratch using the old content as a guide in cases when straightforward conversion is not available.

MITRE ATT&CK Coverage: Leveraging MITRE ATT&CK mapping helps to visualize and validate the current detection coverage of your existing SIEM and provides a roadmap for transition to the new SIEM. Continuous tracking of progress through comparative coverage metrics, including MITRE ATT&CK coverage and per-detection telemetry, ensures equivalency between the old and new SIEM environments, offering a robust and confident transition for enhanced cybersecurity measures. (Note: the CardinalOps platform is built on the MITRE ATT&CK framework and uses specialized, ML-based analytics and feature extraction to map your detections, both out-of-the-box or custom, to the most appropriate ATT&CK technique and sub-technique, producing a heatmap and coverage score that’s continuously updated whenever you add detections or the ATT&CK framework gets updated.)

Identify and Fix Broken Detections: Your network has changed, your security tools have been upgraded to newer versions and log formats, older log sources have been retired, and your monitoring targets have changed. This results in broken rules that will never fire due to misconfigured data sources, missing fields, parsing errors, and other data quality issues. Whether it’s testing rules in the old SIEM or validating the effectiveness of ones in the new SIEM, the CardinalOps platform can continuously analyze all your rules to ensure they have all required prerequisites (log data, field values, etc.), are properly configured, and are firing as they should. Identifying issues with broken rules is only part of the solution, our platform also delivers remediated rules that you can review, test and instantly deploy into your SIEM. 

SIEM Migration: The Pain is Real (But We’ve Got Your Back)

SIEM migration is a multifaceted decision that demands a thorough understanding of existing processes, data structures, detection content, and the unique characteristics of both the old and new SIEM solutions. Whether you decide to stick with your existing SIEM and make improvements, or go full steam ahead with a migration to a new one, CardinalOps is here to lend a hand. Our platform and team of experts have helped customers in both situations by providing a comprehensive view of their detection posture, identifying gaps in MITRE ATT&CK detection coverage, and recommending specific, actionable improvements to optimize their SIEM – old or new.

Interested in learning more about how we help customers through a SIEM migration?