Today, data govern the operations of all the cybersecurity activities. Each time a system is accessed (such as an authentication request, session or configuration change), a digital trace is left behind in the form of a log. These logs are the only way a security team can obtain evidence to determine what is happening within an organization’s infrastructure.
The issue is not the lack of data; it’s the enormous amount of data produced.
Millions of security events occur throughout the enterprise daily from endpoints, servers, network devices, cloud platforms and business applications. Everyday activity generates so much data that it can be extremely difficult to detect suspicious or malicious behavior from all the “noise” generated by daily activity. When both can be present at the same time, it is difficult to find the difference between ‘normal’ noise generated by day-to-day activity versus actual threats.
This challenge has led to a greater need for Security Information and Event Management (SIEM) solutions that play a vital role in today’s overall cybersecurity effort and enable the visibility, context and analysis to identify threats, investigate and provide continual situational awareness within the complex IT environment.
Table of Contents
Understanding SIEM in Practical Terms
SIEM or Security Information and Event Management is a popular cybersecurity tool that collects security data from all sources in the digital space of an organization, so the data can then be analyzed holistically.
All computers, operating systems, applications, and security products produce logs that contain information about what occurred on that specific device. Examples of different types of activity captured in logs are whether or not a user successfully logged onto that device, any attempts made to access files, any network connection, any administrative actions taken, and any errors encountered by the system. While looking at the log from a single system often doesn’t provide a lot of insight, looking at many logs simultaneously can produce meaningful insights into user behavior.
SIEM tools combine logs from many sources, convert them to a common format, and analyze them together. This provides an organization with a single view of security activity across its entire infrastructure.
A centralized view of security data is important for security operations teams. Instead of reviewing multiple logs from many different locations, an analyst can see all of the activity across the organization from one view.
Why SIEM is Critical for Threat Detection
Most cyberattacks do not begin with a dramatic system compromise. Instead, attackers typically progress through multiple stages while attempting to remain unnoticed.
An attacker may first obtain stolen credentials. Once inside the network, the attacker may explore systems, escalate privileges, move laterally between machines, and eventually attempt to access sensitive data. Each step leaves small traces across different systems.
For example:
- Authentication systems may record unusual login attempts.
- Network devices may log unexpected internal traffic patterns.
- File servers may record abnormal data access behavior.
When looking at them independently, this could seem relatively innocuous but collectively, these could be characteristic of a coordinated assault (assaulting).
SIEMs exist to identify these types of relationships between events. By looking for devices with correlated activity across different systems, they assist security analysts in detecting patterns that otherwise would have stayed undetected.
The ability to create this correlation is one of the key reasons SIEM is still a fundamental part of threat detection strategies.
How SIEM Platforms Operate
Although implementations differ between vendors, most SIEM platforms operate through several common processes that transform raw data into actionable security intelligence.
Log Collection
The process begins with collecting log data from across the IT environment. These sources typically include:
- Servers and operating systems.
- Network devices such as firewalls and routers.
- Endpoint security tools.
- Identity and access management systems.
- Cloud infrastructure and SaaS platforms.
- Databases and enterprise applications.
Each of these systems generates logs using different structures and formats.
Data Normalization
SIEM solutions perform analysis by converting incoming logs into a standardized format (known as normalization) so that they can be compared and analyzed together, regardless of the technology in use. Without this step, correlation across systems would be very difficult.
Event Correlation
The SIEM software applies correlation rules and analyzes the event data using a variety of analytical tools to look for trends that would identify any potentially malicious activity.
Correlation engines look at event sequences to find patterns of activity that may indicate malicious behavior. As an example, consider this pattern. A user fails to log in five times. Then they log in successfully from a new location. This may mean someone stole the user’s credentials.
The correlation rules can be based on either “known” or “assumed” malicious activity, historical data patterns, or behavioral analytics.
Alert Generation
SIEM creates alerts when any of their detected patterns raises suspicion. Alerting analysts that a suspicious activity has occurred, which will require investigation. Security operation teams generally monitor alerts via dashboard at a Security Operation Centre (SOC).
Investigate and Analyze
Upon signal generation by SIEM, analysts will investigate that event by using contextual data contained in the SIEM system to reconstruct an event’s timeline through analysis of historical logs to identify if the event is a legitimate threat or simply a benign anomaly.
Investigation and Analysis
The analyst will review the generating alert to research using context from the SIEM; by reviewing historical logs, the analyst can build a timeline to determine if the activity in question is an actual threat or just an anomaly.
SIEM and Incident Investigation
One of the most valuable aspects of Security Information and Event Management appears during incident response.
When a breach is suspected, investigators must determine several key factors:
- How the attacker entered the environment.
- Which systems were affected.
- What actions were performed.
- Whether sensitive data was accessed or exfiltrated.
SIEM platforms provide the historical record required to answer these questions. Because logs are collected and stored all the time, analysts can rebuild a clear timeline before the incident. This visibility enables security teams to understand the full scope of an attack and implement appropriate remediation measures. Without centralized log visibility, investigations often become fragmented and incomplete.
Supporting Regulatory and Compliance Requirements
Aside from the ability to detect threats, SIEM platforms also assist organizations with compliance. Many industry frameworks require organizations to collect security event information and keep logs of those events for audits. Financial services and health care, as well as government agencies, typically require organizations to centrally log security information and track who has accessed that information. Running and maintaining the records manually would present significant operational challenges across multiple systems.
SIEM simplifies compliance by centralizing log management and generating audit-ready reports. Organizations can demonstrate that security monitoring processes are in place and that historical activity records are preserved. For regulated industries, this capability is often a critical requirement.
Operational Challenges with SIEM
Security Information & Event Management is a critical piece of Security because without proper deployment and management, it won’t deliver its intended outcome.
The challenge many organizations face today is “alert overload” a phenomenon that occurs when the correlation rules on the SIEM have not been properly configured to reduce or threshold the normal operational events (alerts). Thus, many of the alerts generated are indicative of “normal” operational behavior rather than “true” threats.
Alert fatigue has been seen by many organizations as negatively impacting their analyst’s ability to perform their duties efficiently and timely in response to alerts.
Organizations are also challenged by the scale in which they now have large data environments. Large enterprises generate large volumes of log data daily, and in many cases need an elastic infrastructure to manage the storage and processing of that data.
As a result, organizations are starting to combine SIEM with other Security technologies to provide greater context to alerts and improve the accuracy of detecting “true” threats.
SIEM’s Role in a Modern Security Architecture
The evolution of the cybersecurity field is rapidly changing the way that companies are doing business today as they move away from traditional business models towards more integrated and digital solutions involving both physical and virtual spaces. Today, businesses operate within a multi-cloud world, where they are leveraging on-premises infrastructure, multiple cloud-based solutions, remote work-from-home solutions, and external business partnerships.
The increase in complexity of the above mentioned mixed-use business operations create numerous attack vectors for potential cybercriminals while also generating a large body of security events. Centralized visibility is therefore critical in any modern mixed environment for enterprises.
SIEM (Security Information and Event Management) platforms deliver this centralized visibility to security teams tasked with monitoring disparate technological infrastructures and systems. Furthermore, combining the functionality of SIEM solutions with other systems such as endpoint detection and response systems, network analytics solutions, and automated response technologies provides a complete security monitoring solution.
The Continuing Importance of SIEM
Even though cybersecurity technologies have evolved at a fast pace over the years, SIEM is still one of the most deployed security technology solutions in enterprise environments today.
SIEM’s role is simple but critical – it collects security data, processes it with context, and generates the insights necessary to identify and investigate potential Security threats.
As organizations continue to grow their digital infrastructure, the demand for centralized visibility will continue to grow. Security Operations teams need to understand both what events are happening throughout their environment and how those events relate to each other in order to provide full visibility on security. Security Information and Event Management systems provide the analytical foundation required to make that understanding possible.
