How to reduce the impact of a data breach with SIEM

Why businesses need to deal with data breaches quickly

In today’s rapidly changing threat landscape, businesses must respond to data breaches with speed and agility because cyber criminals are always coming up with new attack vectors, malware variants, and techniques. Organisations that let their defences lapse and don’t keep up to date may become vulnerable to new threats.

Cyber attackers often act quickly after discovering vulnerabilities, and the longer the breach goes unnoticed, the longer they have to exploit sensitive data or cause serious damage. Failure to detect a data breach in your system can have disastrous consequences, including monetary losses, reputational damage, decreased customer trust, and legal ramifications.

Your company must remain vigilant in order to safeguard its assets, data, reputation, and, most importantly, the trust of its customers. Acting quickly in the face of a data breach is more important than ever for maintaining a safe and resilient business environment.

Detecting a potential breach early on can help you contain and neutralise attackers before the security event spiral outs of control.

Understanding SIEM technology

SIEM combines log monitoring and event management systems to detect suspected breaches and unusual activity in real time. A SIEM collects and analyzes security event data from sources such as firewalls, servers, and network devices in order to identify security incidents and provide security teams with actionable insights.

SIEM solutions typically include the following components:

• Collect logs from various sources and correlate them to identify unusual activity.
• Analyze collected logs and events to gather details, enabling businesses to take appropriate action.
• Detect security threats and vulnerabilities using threat intelligence and behavioural analysis.
• Generate reports to help meet compliance requirements and providing insight into weaknesses that could lead to a data breach.

The goal of a SIEM solution is to help businesses stay ahead of potential breaches by detecting suspicious activity quickly and providing context for subsequent remediation. This assists organisations in safeguarding sensitive data and systems against unauthorised access.

SIEM is a must-have tool for companies looking to maintain a strong security posture and defend against an ever-changing threat landscape.

However, managing a SIEM solution can be difficult, and it requires a high level of expertise to operate effectively. This is why many organisations opt for a managed SIEM service. This is a security solution that offers all of the benefits of SIEM without the burden of managing it on an ongoing basis.

With a managed SIEM service a team of security experts handle everything from SIEM infrastructure deployment, configuration, and maintenance. This type of service typically includes 24/7 monitoring, alerting and a basic level of incident response, ensuring that any security issues are addressed as soon as possible.

Types of log data

Coverage is a critical aspect of a SIEM solution. A SIEM collects security log data from various sources and consolidates it into a single location, including system logs, network logs, application logs, security logs, audit logs and cloud logs. These logs are ingested either via APIs or physical devices with collector agents installed. To ensure comprehensive coverage, it is advisable to gather as much security log data as possible.

Logs can record very granular data such as timestamps, user actions, error codes, and other relevant metadata, which provides a clear picture of what occurred in the system and information for effective troubleshooting, debugging, and analysis. Additional contextual information may also be available via log data, such as session IDs, request headers, and detailed stack traces, which are useful for diagnosing complex issues.

Ultimately the more data you have to bring into your SIEM solution that provides security value, the easier it is to form correlations and conduct investigations.

High fidelity vs low fidelity alerts

How do you get the most out of your SIEM solution and detect threats as early as possible? One way to do this is by combining two types of alerts; high fidelity and low fidelity.

High fidelity and low fidelity refers to the level of detail and context that a security alert provides. Combining these two types of alerts from your log data gives your business a much better understanding of what is happening in your environment when a security event occurs.

Let’s look at the difference between them:

High fidelity

A high fidelity alert could be a clear indication that a security incident or data breach has already occurred. This type of alert usually provides enough context on its own for a SOC analyst to instantly understand that it is a genuine issue that needs attention. These type of alerts usually contain detailed information about particular security events, actions, and system activities.

Endpoint protection tools can be a great source of high fidelity alerts. For example, the detection of Mimikatz on a host would almost certainly indicate malicious activity that requires immediate attention. SOC teams can be presented with an insurmountable level of security alerts every day, as a result, these types of alerts are often prioritised by analysts and should be investigated as soon as possible.

Low fidelity

Low fidelity alerts can include day-to-day events like user logins, which may not directly be an indication of compromise but can provide context when investigating high-fidelity alerts. Low fidelity alerts are therefore typically not actionable on their own and need further context before a decision can be made.

A low fidelity alert could be multiple failed login attempts from a single IP address. This alert is triggered when a single IP address fails to authenticate successfully multiple times in a short period of time. This can be considered as low fidelity because it may be triggered in legitimate scenarios where a user forgets their password or accidentally mistypes it multiple times. Such situations may not always indicate malicious activity; however, patterns like these from low fidelity alerts should be monitored as they may indicate a potential brute-force attack.

Combining high fidelity and low fidelity alert data is essential because it enables a thorough understanding of a system or security incident. The more information a SOC team has at their disposal, the better they can fully triage and investigate alerts and make informed decisions.

Getting value from your SIEM solution

To make the most of your SIEM solution, here are five things you need to consider:

• Understand your environment: Take the time to thoroughly understand what requires protection and prioritisation. With this information, you’ll be able to collect relevant logs from critical systems, laying the groundwork for a solid security operations strategy. Knowing where sensitive data resides and potential attack vectors exist in your network allows you to tailor the monitoring setup to focus specifically on those high-priority areas.
• Establish a baseline: Develop a thorough understanding of the day-to-day interactions and operations of your systems. This knowledge allows you to define normal behaviour patterns, making it easier to identify anomalies and potential threats. Making a baseline for your infrastructure improves your ability to detect deviations. For example, by monitoring normal user activities and system events, you can spot abnormal patterns that indicate suspicious behaviour more easily.
• Strike a balance between high and low fidelity alerts: Combine high fidelity alerts that indicate significant security events such as blocked malware attacks, with low fidelity alerts that capture routine activities, such as user logins. By combining these two types of alerts, you can better correlate events and confirm potential threats. A high fidelity alert about a blocked intrusion attempt, for example, combined with low fidelity login records for the targeted account, can provide valuable context for further investigation.
• Assess your cybersecurity knowledge and expertise: Effective security incident investigation necessitates the right expertise. Consider a managed SIEM solution with a Security Operations Centre (SOC) if your organisation lacks the necessary cyber security skills or personnel. SOC teams have the experience to investigate and respond to threats proactively, allowing you to effectively safeguard your systems by leveraging their expertise. A skilled SOC team, for example, can help to quickly identify and mitigate a data breach before significant damage occurs.
• Incorporate SIEM into your incident response strategy: Include log data analysis in your incident response training. During an incident, log data contains vital indicators that guide the appropriate next steps. Ensure that your internal team is well-versed in the use of the SIEM solution and the incident response process, allowing for a quick and effective response. Containment, eradication, and recovery should all be part of your incident response strategy. For example, when confronted with a suspected breach, the SIEM solution can assist in tracing the origin of the attack and isolating and neutralising affected systems.