The 6 Stages of the Cybersecurity Incident Response Lifecycle

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Introduction - Why do we need Incident Response?

• No matter how secure you think your systems are, no one is completely immune to cyber attacks.

• Whether it’s a phishing email someone accidentally clicks or a vulnerability an attacker manages to exploit, incidents will happen.

• That’s where Incident Response comes in.

• Think of it like having a fire drill plan. When something goes wrong, you don’t want panic. Instead, you want a clear, step-by-step process to follow.

• The faster and smarter you respond, the less damage is done.

• In this blog, I’ll break down the 6 key stages that make up a solid incident response strategy.

• But before we do that, let’s quickly look at how organisations protect themselves before an incident even happens , with something called Defense in Depth.

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Defense In Depth

• Defense in Depth is a fancy term for a simple idea: don’t put all your trust in just one line of defense.

• Think of it like securing your home:

  • You lock the door (perimeter security),

  • Then you add a security camera (monitoring),

  • Maybe even a motion sensor alarm (detection),

  • And finally, a loud dog (physical deterrent).

In cybersecurity, the same layered approach applies:

• Firewalls protect the edge,

• Antivirus stops known threats,

• Intrusion Detection Systems (IDS) catch suspicious behavior,

• Access Controls limit who can touch what,

• Regular Backups ensure you’re not left in the dark if things go wrong.

• Each layer makes it harder for an attacker to succeed. But still, no system is perfect, which is exactly why Incident Response exists.

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The 6 Stages of the Cybersecurity Incident Response Lifecycle

• Despite our best efforts with firewalls, monitoring tools, and strong passwords, sometimes attackers slip through.

• That’s where a well-defined Incident Response Lifecycle becomes crucial.

• These six stages help organizations react quickly, minimise damage, and learn from every security event.

1. Preparation

   • This is the “before anything goes wrong” phase.

   • Organizations set up incident response policies, build their response teams, define roles, and make sure everyone knows what to do when things go sideways.

   • This is like a fire drill you would have probably done at some point in your organisation.

2. Identification

   • Time to detect whether something is an incident.

   • Maybe it’s an alert from a SIEM tool, a suspicious login attempt, or someone clicking on a sketchy link.

   • This stage is also crucial to filter out a real threat from noise ( false positives ).

3. Containment

   • Once confirmed, the goal is to stop/limit the bleeding.

   • Short-term containment might mean isolating affected systems.

   • Long-term containment involves patching vulnerabilities, changing credentials, or applying network segmentation.

   • Anything that keeps the threat from spreading.

4. Eradication

   • Get rid of the attacker’s access, malware, or any backdoors they may have left behind.

   • This could involve deleting malicious files, removing unauthorized user accounts, or reimaging systems.

   • This stage is about making sure the threat is completely gone before moving on.

5. Recovery

   • Now that things are cleaned up, it’s time to bring systems back online (safely).

   • This involves monitoring for any signs of re-infection, restoring services, and making sure everything works as expected.

   • Recovery needs to be slow and cautious, not rushed.

6. Lessons Learned

   • Every incident, big or small, is a chance to improve.

   • This is not a stage for the blame game. Instead the team conducts a post-mortem: What worked? What didn’t? How can we respond faster next time?

   • Updating documentation, training, and controls happens here.

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Real-World Example of the Incident Response Lifecycle

• Let’s walk through a simple scenario to see how each stage applies in action.

• Incident

  • A junior employee receives a phishing email that looks like it’s from HR.

  • They click on a link and unknowingly enter their credentials into a fake login page.

  • The attacker uses those credentials to access the company’s internal system.

1. Preparation

   • The organization had security awareness training in place and logging enabled on critical systems.

   • The incident response team had a playbook for phishing attempts.

2. Identification

   • The security team notices suspicious login activity from an unusual IP address using the junior employee’s credentials.

   • An alert is triggered in the SIEM system.

3. Containment

   • The account is immediately disabled, and the system they accessed is isolated from the network to prevent further movement.

4. Eradication

   • Security analysts scan for malware and remove a script the attacker planted.

   • They change all exposed credentials and patch a vulnerable third-party plugin identified during the investigation.

5. Recovery

   • The isolated system is reimaged and restored.

   • The user account is re-enabled with new credentials.

   • Monitoring is increased for 72 hours to ensure the threat is gone.

6. Lessons Learned

   • The team conducts a review and identifies that multi-factor authentication (MFA) wasn’t enabled for the junior employee.

   • Going forward, MFA is enforced for all staff, and phishing simulations are increased.

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Final Thoughts

• Cybersecurity incidents aren’t a question of if, but when.

• Having a structured, well-understood incident response lifecycle helps your team move quickly, reduce damage, and bounce back stronger.

• I wrote this blog because whether you're part of a security team, a beginner in cybersecurity, or just someone curious about how organizations stay safe , understanding these six stages is a crucial step.

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What’s Next ?

• My next blog will cover ‘Top 10 Common Cyber Attacks and How They Work’.

• This is the 4th blog of the series where I document my path from beginner to cybersecurity professional — one certification, one tool, and one lab at a time.

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