SOC vs SIEM vs XDR vs MDR: What’s the difference & which do you need?

It’s easy to get buried under acronyms. SOC, SIEM, XDR, MDR — they all sound like must-haves, but do you need them all? And what do they really do?

Security and IT leaders are faced with a vast number of tools, services, and strategies to safeguard critical assets. Among the most common of these functions and tools are the SOC, SIEM, MDR and XDR. Each has a unique role in detecting, managing and responding to threats. Knowing how these elements work together within your cybersecurity programme is key to faster, more effective defence. 

In this blog, we’ll break down what each of these is and their place within a cybersecurity environment. 

What is a SOC?

A Security Operations Centre (SOC) at its core encompasses the capabilities, processes and team responsible for detecting, managing and responding to security incidents.

Read the full Guide to SOC as a Service

Think of the SOC as the operational core of your business’s cybersecurity. SOC teams are typically comprised of analysts, engineers, threat intelligence specialists, and incident response specialists who manage, tune, and monitor a range of security tools, including Security Information and Event Management (SIEM) platforms, MDR (Managed Detection & Response) solutions, or XDR (Extended Detection and Response) solutions. These tools help detect suspicious activity and investigate, and respond to security alerts.    

For organisations, there is no one-size-fits-all approach to a SOC; they can be entirely in-house, entirely outsourced to a managed security Operations provider (commonly referred to as SOC as a Service) or operate in a hybrid arrangement between the two. Our SOC expert discusses this very topic in our latest article: “SOC vs SOCaaS: The difference between traditional SOCs vs SOCaaS“.

Which one you pick will depend on a multitude of factors, such as your organisation’s size and resources, your unique risk profile, and the availability of internal expertise.  

In general, building traditional in-house SOCs comes with drawbacks that make it impractical, particularly for small and medium-sized businesses. These include: 

• Significant upfront and continuous investment is needed. 
• Difficulties in hiring and retaining skilled staff, as well as those willing to undertake rotating shifts to achieve 24/7 coverage. 
• Managing multiple integrations and security products used in the organisation. 

The benefits of SOCaaS result in reduced workload and resource strain; SOCaaS providers take away the trouble and do most of the legwork for you. Outsourcing your SOC means you don’t have to commit to the substantial and ongoing commitment of resources, time and budget that a traditional SOC would entail.

Continuous monitoring, processing and review of vast volumes of logs are all handled by experienced, skilled analysts and engineers who also investigate triggered alerts and respond to any security incidents.  

What is a SIEM?

A Security Information and Event Management (SIEM) system is the core tool used within a SOC to detect and respond to incidents. At its heart, a SIEM is a centralised log collation platform that collects logs from across an organisation’s infrastructure and correlates them to help surface potential threats that may otherwise slip through the cracks.

On its own, a SIEM will not respond to the majority of events, but when used in tandem with Automated Investigation and Response tools, some automations are possible; SOCs use automation workflows to provide visibility and context to alerts, effectively telling a story through logs.  

At Evalian, the Microsoft Sentinel SIEM integrates with various data connectors to provide visibility into standard and bespoke log sources. Sentinel is a cloud-native SIEM that provides cyberthreat detection, investigation, response and proactive hunting, with a view across your estate.

By utilising threat intelligence streams, Evalian further enriches detections and log events with malicious Indicators of Compromise (IOCs) used by threat actors. 

What is XDR?

XDR or Extended Detection and Response builds upon a traditional MDR by integrating detection and response across multiple layers, such as emails, endpoints, servers and cloud environments while leveraging machine learning to apply more context-aware detection.  

Take this example, a phishing email that leads to credential theft, which the attacker uses to access a cloud app and install malware on a workstation.  In a traditional setup with just a SIEM and no XDR tooling, this connection can potentially be missed; however, with XDR, these events will be tied together and initiate a coordinated response, e.g. isolating the endpoint, revoking sessions, disabling accounts and alerting the user. 

This takes some of the strain from security teams, allowing them to more easily manage incidents. XDR can also implement anomaly detection; after establishing baselines for events, Evalian’s XDR tools are able to alert upon behavioural anomalies, further increasing chances of catching attacks before they happen. 

Microsoft Defender is used at Evalian as it integrates into Microsoft Sentinel, allowing data to be fed into the SIEM for broader visibility and long-term retention, alongside automated investigation and response capabilities to automatically respond to threats. Defender is made up of multiple other products, including: 

Identity: Compromised user accounts, insider threats and advanced persistent threats are monitored by Evalian using user behaviour and activities across domain controllers. 

Endpoint: Evalian helps organisations prevent, detect, investigate, and respond to threats on their endpoints (servers, laptops, mobile phones).  

Office 365: Evalian protects Office 365 users (Teams, Exchange, Outlook, etc) against phishing, business email compromise and malware through Safe Links and Anti-phishing protection. 

Cloud Apps: Provides visibility, control and threat protection for cloud apps. Defender for Cloud Apps can monitor and control access to Software as a Service (SaaS) applications, as well as detect risky behaviour such as data exfiltration. 

Exposure Management: Through proactive identification and reduction of an organisation’s attack surface, Evalian uses exposure management to discover unmanaged and internet-facing assets, simulate attacker behaviour and prioritise remediation efforts. 

Threat Intelligence: Microsoft Defender Threat Intelligence provides insight into global cyber threats, assisting Evalian in understanding the techniques, tactics and procedures they use. 

What is MDR?

Lastly, there is Managed Detection and Response (MDR), which is an evolution of a SOC where traditionally analysts would wait for alerts to come in before responding. The core components of Managed Detection and Response are: 

Endpoint Detection: Endpoints like servers, computers and mobile devices are typically the main target for attackers seeking to gain access to the network; endpoint detection is critical in monitoring and protecting individual devices. 

Threat Intelligence & Analysis: This is the process of collecting and analysing intelligence and assessing whether the organisation is vulnerable to those threats.

Incident Response: A structured methodology for addressing and managing security incidents both during and after remediation. This process involves swift identification, containment, removal and recovery efforts to minimise the impact of attacks. A successful incident response plan doesn’t stop after recovery, though; measures need to be implemented to prevent similar incidents from happening in the future and prioritise business continuity. 

Threat Hunting: A proactive approach that involves actively and continuously searching for potential threats that may have bypassed detection. Analysts utilise their experience to identify abnormal behaviour. Threat hunting can also emerge from threat intelligence news, with new IOCs being discovered. 

All these features combined aim to reduce an organisation’s time-to-detect (the time it takes for an organisation to detect a threat).  

Differences between MDR and SOCaaS can vary between providers, with some SOC services only performing level 1 tasks like monitoring, alerting and passing suspected true positives to you, leaving you to perform your own triage and response actions.  An MDR’s scope is typically a lot narrower, often not including the extra features you get with SOCaaS like communication, customisation and insights. 

What Is SOCaaS?

Now that you understand the differences between a SOC, SIEM, XDR and MDR and how they fit into a security function, we can go into SOC as a Service; the best SOCaaS providers will tailor to each organisation’s needs, removing the need to build and manage their own SOC, something smaller companies, especially, may struggle with.

SOCaaS providers remove the complexity from managing your security estate, streamline scalability, introduce predictable costs and come without the need to hire and train your team of analysts. 

Evalian completely combines an MDR and SOCaaS with 24x7x365 monitoring, providing services such as: 

• 24x7x365 Monitoring: Continuous monitoring of your estate to detect threats and respond to incidents in real time. 
• Incident Containment & Response: Security analysts will triage, investigate and mitigate incidents – including out-of-hours response. 
• Standard & Custom Detection Rules: A library of standard detection rules and then extra detections custom-created for your organisation. 
• Threat Enriched Monitoring: Logs and alerts are enriched and contextualised using threat intelligence to improve detection accuracy. 
• Threat Hunting: Reactive and proactive hunting in response to alerts and threats that have evaded detection based on threat intelligence. 

Evalian’s experienced analysts ensure that the hardships of security are taken care of, enabling you to sit comfortably knowing your organisation is protected and secure. 

Download your guide to choosing a SOC provider

If you’re at the research stage of choosing a SOCaaS provider, it can be a tricky decision. Many SOC providers look like they offer the same services on the surface, but won’t tell you if they can’t isolate a compromised laptop straight away, or if their escalation process is unclear.

Our SOC team have made an essential SOC Provider Checklist to help you ask the right questions when deciding on what SOC provider to go with. It’s the same set of checks we use ourselves.

Download your free copy of the SOC Provider Checklist.

Ready to discuss outsourced SOC? 

Contact our expert team today to discuss your requirements and understand how our outsourced CREST accredited SOC as a Service can support your organisation. 

Read our comprehensive Guide to in-house SOC vs outsourced SOCaaS, or skip ahead and calculate your SOC cost using this handy free SOC Cost Calculator.