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What Are SIEM and SOC? How They Differ and Work Together

SIEM is software, a SOC is a team. Log correlation, alert fatigue, the math behind 24/7 staffing, SOAR and MDR, and what regulators in Türkiye expect.

Oğuzhan Gerçek··9 min read
What Are SIEM and SOC? How They Differ and Work Together

Short answer: A SIEM (Security Information and Event Management) is software that collects logs from across an organization's systems in one place, links related records together and raises an alert when it sees a suspicious pattern. A SOC (Security Operations Center) is the team that looks at those alerts, confirms what happened and responds. One is the tool, the other is the team and process that use it: a SIEM without a SOC piles up alerts nobody reads, and a SOC without a SIEM cannot see what to look at.

What is a SIEM?

Gartner coined the term SIEM in 2005. It merged two older product categories: security information management (SIM), which stored logs and reported on them, and security event management (SEM), which watched events in real time. Today's SIEM products do both, and they do four basic jobs:

  • Collection: They take logs from firewalls, Active Directory, servers, endpoints, cloud accounts and applications.
  • Normalization: They map records in different formats onto common fields: user, source IP, time, event type.
  • Correlation: They combine events that look harmless on their own. In NIST's definition, correlation is finding relationships between two or more log entries. A run of failed logins, then a successful one, then a privilege escalation a few minutes later is noise when you look at each event separately and an attack chain when you look at them together.
  • Retention and search: They keep logs searchable so that months after an incident you can still answer "what did this account touch that day?"

Well-known products include Splunk, Microsoft Sentinel, Google Security Operations, IBM QRadar and Elastic Security; on the open-source side, Wazuh is widely used. The market has been changing hands since 2024: Cisco acquired Splunk, and QRadar's SaaS business moved to Palo Alto Networks. Microsoft will stop supporting Sentinel in the Azure portal after March 31, 2027, moving its management to the Defender portal. When you choose a product, look at its roadmap as closely as its current features.

What is a SOC?

MITRE defines a SOC as a team, primarily made up of cybersecurity specialists, organized to prevent, detect, analyze, respond to and report on cybersecurity incidents. A SOC, in other words, is not a room or a product. It is a function.

A classic SOC works in three tiers:

  • Tier 1 (triage): Reviews incoming alerts and separates real incidents from false alarms.
  • Tier 2 (incident response): Investigates confirmed incidents, contains them and manages recovery.
  • Tier 3 (threat hunting): Looks for attacks that have not triggered an alert yet and writes new detection rules.

Some teams work without tiers. Whichever model you pick, the core does not change: someone has to look at every alert, decide what to do and record the decision.

The difference between SIEM and SOC

  • A SIEM is software: it collects logs, correlates them and raises alerts. You buy it under a license or a subscription.
  • A SOC is a team and a process: it confirms alerts, responds and tunes the rules. You build it in-house, buy it as a service or run a mix of both.

The most common mistake is to assume that installing a SIEM finishes the job. According to Vectra's 2026 research, organizations receive an average of 2,992 security alerts a day, and 63% of them are never addressed. In 2026 research from Microsoft and Omdia, an estimated 46% of alerts turn out to be false positives and 42% go uninvestigated. Generating alerts is cheap. The team and process that look at them are what cost money.

How one alert travels

The flow below is an example; the real steps depend on each organization's own authority matrix.

  1. At 3 a.m., someone logs in to a user's account over VPN from abroad, and the VPN appliance logs it.
  2. The SIEM matches that record with an Active Directory entry showing the same account signed in from the Istanbul office half an hour earlier. An "impossible travel" rule fires.
  3. A Tier 1 analyst opens the alert and checks whether the user really is abroad at that hour.
  4. If the incident is confirmed, it moves to Tier 2: sessions are terminated, the password is reset and the account's recent access is reviewed.
  5. When the incident is closed, the rule is reviewed: could it have been caught earlier, and is the threshold right?

A common way to measure detection coverage is MITRE ATT&CK, a knowledge base of adversary tactics and techniques built from real-world observations. Marking on ATT&CK which rule catches which technique turns "what are we not seeing?" into a concrete list.

What are SOAR, XDR and MDR?

Three more acronyms circle around the SIEM:

  • SOAR (Security Orchestration, Automation and Response): Combines incident response, automation and threat intelligence in one platform. When an alert is confirmed, it runs steps such as locking an account or blocking an IP automatically. Many SIEM products now include this capability.
  • XDR (Extended Detection and Response): Brings detection and response across several security products, such as endpoint, network, email and cloud, into one platform.
  • MDR (Managed Detection and Response): In Gartner's definition, SOC functions delivered remotely as a service. For organizations that cannot staff their own 24/7 team, it is the most direct option.

The value of automation can be measured. In IBM's Cost of a Data Breach Report 2026, the global average cost of a breach is $4.99 million. Organizations that use AI and automation extensively in security pay an average of $1.93 million less per breach than those that use none.

The staffing math of a 24/7 SOC

24/7 monitoring is not a principle; it is a staffing calculation. A year has 8,760 hours. After leave, public holidays and training, one person works roughly 1,800 hours a year. Keeping a single seat filled all year therefore takes about five people. That covers one Tier 1 seat only; Tier 2, Tier 3, rule development and team management come on top.

On the other side of the calculation is detection speed. In Mandiant's M-Trends 2026, the global median time attackers stayed undetected was 14 days. In 52% of cases, organizations detected the intrusion themselves; in the rest, they heard about it from an outside party or from the attacker. The same report notes that standard 90-day log retention policies leave organizations completely blind to the initial access vector of intrusions that stay hidden for months. How far back your SIEM can search is therefore not a licensing detail. It is your detection capability.

Whether you build your own SOC, buy MDR, or cover business hours in-house and the rest with a service is a choice to make with these two calculations in hand. Whatever the model, it should be written down who decides once an alert is confirmed; we give a template in our incident escalation matrix article.

What regulation in Türkiye requires

In Türkiye, log monitoring and incident response are an obligation, not a choice, for many organizations:

  • Banks: The BDDK regulation on banks' information systems requires audit logs to be kept for at least five years and an internal SOME (cyber incident response team) to be set up. It tasks that team with routinely following audit logs through the log management system and checking for meaningful correlations between them. That is the regulation's description of a SIEM and a SOC.
  • Critical infrastructure: Cyber Security Law No. 7545 requires the organizations it covers to report the cyber incidents they detect to the Cyber Security Presidency without delay. An incident nobody detected cannot be reported; we explain the law's scope in Are you covered by the Cyber Security Law?
  • Public sector: The Information and Communication Security Guide, published for public institutions and critical infrastructure operators, lists central log management and log analysis tools as separate measures under keeping and monitoring audit trails.

If an incident also affects personal data, the KVKK notification clock starts. You can find how to prepare in 72-hour data breach notification readiness, and which log to keep for how long in log retention periods.

Questions to ask when choosing a SIEM

  • Which log sources are connected, and which are left out? Count cloud and SaaS accounts too.
  • What is the license measured on: daily data volume, events per second (EPS), or the number of protected users and devices? What happens to the bill when log volume doubles?
  • How many days of logs are instantly searchable, and how many sit in archive? How long does it take to bring archived logs back?
  • Are the rules mapped to MITRE ATT&CK, and which techniques are not covered?
  • What share of alerts are false positives, and who tunes the rules, how often?
  • How many minutes does it take for someone to look at a critical alert out of hours, and is that time measured?

Frequently asked questions

What does SIEM stand for? Security Information and Event Management. It is software that collects and correlates logs and raises alerts on suspicious patterns.

What does SOC stand for? Security Operations Center. It is the team that monitors security alerts, confirms incidents and responds to them.

Is SIEM the same as log management? No. Log management collects, stores and indexes records. A SIEM adds correlation and alerting on top; its goal is detection, not storage.

What is the difference between SIEM and SOAR? A SIEM detects and raises alerts. A SOAR platform automates the response steps that follow a confirmed alert.

Does every company need a SOC? Every company needs the SOC function, because someone has to look at the alerts. That does not mean building your own 24/7 team; an MDR service, or a model where an internal team works alongside an external service, can do the same job.

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