SOC/CSIRT Basic and fundamental concepts

March 5, 2026 ยท View on GitHub

ToC

What is a SOC?

SOC definition:

As per MITRE paper (SOC strategies, see below): image

Typical SOC:

Data, tools, and capabilities: image

Evolution of SOC in time

Some people may consider SOC has evolved in time, as the following drawing shows (from this article):

image

I do believe it mostly depends on the context (environment to the monitored), and the cyber maturity. And on top of that, AI (meaning Artificial Intelligence) still does not exist per say....

SOC activities vs. CSIRT activities

SOC activities:

As per ENISA's whitepaper, a minimal set of services for SOCs usually includes those in bold below in accordance with the FIRST services framework:

image

CSIRT activities:

As per ENISA's whitepaper, a minimal set of services for CSIRTs usually includes those in bold below in accordance with the FIRST services framework:

image

SOC vs. CSIRT vs. ISAC vs. PSIRT

As per this article on LinkedIn:

image

image

What is a SIEM? What for?

As per Gartner's glossary:

Security information and event management (SIEM) technology supports threat detection, compliance and security incident management through the collection and analysis (both near real time and historical) of security events, as well as a wide variety of other event and contextual data sources. The core capabilities are a broad scope of log event collection and management, the ability to analyze log events and other data across disparate sources, and operational capabilities (such as incident management, dashboards and reporting).

And as per this article (in French):

image

SOC mission and context

SOC operating context:

As per MITRE paper (SOC strategies, see below):

image

SOC/CERT processes and workflows

Incident response lifecycle (detection // incident response):

As per NIST SP800-61 rev2 paper (see below): image

As an IT security teacher used to tell his students, like a SOC motto: "Without response, detection is useless" (Freely inspired from Bruce Schneier, Secrets and Lies: Digital Security in a Networked World book).

Typical incident handling workflow:

As per ENISA paper see below:

image

SOC/CERT procedures:

  • Write and maintain in time alerts/incident handling procedures.
    • My recommendation: take those from CERT-SG: IRM, as an example, and have a look at the DFIQ
    • You may want to have a look at:
  • Leverage community-standards to define the common questions and checkpoints, for incident response :
    • My recommendation: DFIQ

What is purple/red/blue team?

Quoting Lutessa (article in French):

image

What is an attack lifecycle?

As per Mandiant article:

image

What are the most common infection vectors?

Based on experience, and on numerous malware statistics, the following ones should be considered as priority:

  • emails;
  • web browsing;
  • USB sticks / removable storage;
  • exposed (internet facing) services/apps and equipments (e.g.: appliances)

What are the differences between antivirus and EDR?

CapabilityAntivirus (part of EPP)EDR
Console APIQuite limitedDepends on the vendor: some provide a limited API and force to use their console, some others provide an API that allows to implement a "single pane of glass" approach in the SIEM/SIRP
Detection of malicious filesHash-based (even if not pure MD5 per say), or binary portions based. Sometimes code emulation-basedHashed-based (but backed by standards like OpenIOC sometimes)
Detection of common malwareAV vendors have knowledgebase of billions of samples (often called something like "cloud protection")Out of scope: EDR does not replace AV
Detection of advanced malwarePartial, depends on the use case and vendorFull capability (IoC-based, behaviour-based, ML-based, etc.)
Detection of malicious trafficDepends on the antivirus solution (some may, some may not)Full capacity (HTTPs and others), endpoint-wide
Detection of malicious behaviourLimitedMachine-learning-based or with embedded advanced detection logics (like for drive-by download technique detection)
Detection on custom IoCQuite uncommon (some may, some may not)Standard: detect custom MD5/SHA1/SHA2, URL/IP/Domain, file path, file name, etc.
Detection based on loggingLimited: only what is detected is being loggedFull capability: system, network, and security events history is collected and centralized (often called telemetry), allowing to build custom detections in the SIEM
Investigation (eg: on detection cases)Very limitedFull capability: system, network, security events history is collected and centralized (often called telemetry), allowing to investigate deeper in the EDR or SIEM console
Sample remote collectionQuite uncommonFull capability: file sample collection, memory collection (RAM dump), etc.
Containment of endpointUncommon (only a few solutions provide it AFAIK)Full capability
Containment: network trafic blockDepends on the antivirus solution (some may, some may not)Full capability, endpoint-wide: block on IP or URL at will
Containment: file hash blockDepends on the antivirus solution (some may, some may not)Full capability, endpoint-wide: block on hash or file path at will
Remediation: malware cleaningLimited to malicious file deletion or quarantineSame as AV. EDR does not replace a real backup!

EDR / MDR / NDR / XDR ?

I would recommend this article and picture: image

IMHO, XDR is more like a mini-SIEM (limited capabilities compared to a full-blown SIEM), with admin capabilities on security solutions (at least for the same vendor as the XDR) and even sometimes orchestration capabilities.

End

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