Security Engineer Starter Guide: Incident Response & Forensics
Cybersec Café #53 - 02/04/25
Cybersecurity is commonly framed as a battle between offense vs defense. Good vs bad. Attackers vs defenders.
Today we’ll be exploring those at the forefront of the clash between both sides: Security Incident Response & Forensics Engineers.
These are the specialists who investigate, contain, and mitigate threats when real cyber attacks happen.
Success in incident response isn’t just about tools and playbooks, it comes down to intuition and preparation.
If you’re looking to break into Incident Response, here’s what you need to know.
The Preparation
Incident Response isn’t just about responding to incidents. Nope, it’s about the preparation that happens behind closed doors.
Success often hinges on confidence in your technical abilities, deep knowledge of your environment, and well-defined team processes.
Let’s break down the key steps to make sure you’re prepared for the next attack.
Environment Knowledge
This most important step of becoming a successful Incident Responder is understanding the environment you’re defending inside-and-out.
Start by asking yourself these key questions:
What kinds of machines does my organization use?
Do we have an inventory of our machines, and how are they managed?
What applications do we have? What do they do? Which ones store sensitive data?
What response actions do I have available to me?
Once you understand what exists is in your environment, you also need to know who is in your environment:
Who owns which applications?
Who are the Subject Matter Experts (SMEs) for key systems?
Who are the key stakeholders that would need to be involved in incidents?
Incident Response is as much about people as it is about systems. Knowing who to call when things go south is just as critical as knowing where to look.
Beyond people and assets, you need to establish a clear picture of where everything lives:
What systems generate logs?
Where are those logs stored?
How do you retrieve them?
Unless your budget is completely unlimited and you have perfect infrastructure, it’s likely all your logs aren’t living under the same roof.
To avoid scrambling during an incident, document everything - a mind map, an internal wiki, even a simple spreadsheet.
Whatever works for you.
At the end of the day, you can’t do your job effectively if you don’t know where to look.
Preparation starts with visibility.
Query Skills
Knowing where data lives is only half the battle. You also need to know how to retrieve it and shape it to your needs.
We do this through queries.
Every environment is different, meaning the query languages you’ll use will vary. But if you master one, you’ll be able to easily pick up others.
The ability to query efficiently and effectively can help you spot anomalies, investigate threats, and extract insights faster.
I covered why being able to query is an essential cybersecurity skill in an article last week, check it out here.
Tooling
The right tools can make all the difference in a high-pressure incident.
But tools are only worth something to you if you’ve configured them correctly and know how to use them.
You’ll be hard pressed to find a security tool that’s just “plug-and-play.” They require setup, fine-tuning, and testing to ensure they work when you need them most.
The last thing you’ll want to be wondering mid-incident is if your tools will actually do their job.
To prepare:
Adjust configurations to your environment.
Fine-tune automation
Test regularly to build confidence in their reliability.
Don’t rely on memory either. Document your key processes.
Incident Response workflows aren’t always frequent, so having a clear and concise reference can save valuable time.
And along with that note - make sure to get hands-on experience.
Security tooling isn't always intuitive. You need to understand exactly what happens when you push a button before you’re forced to push it for real.
Documentation
Beyond tooling, having formalized Incident Response documentation is essential.
Having a well-structured IR document transforms what can feel like a chaotic, time-consuming process into an efficient, repeatable workflow.
The last thing you’ll want to do mid-incident is to waste time figuring out what to document, where to document it, and how to document it.
I’ve detailed exactly how you can create your own Incident Response Documentation along with a template for download here, but here are some basics for you:
Lay everything out in advance. Make it easy to use. Fill out pieces you need and delete others you don’t.
Define Common Roles, such as IR Lead, IR Second, and the Subject Matter Experts (SMEs) so stakeholders know who is responsible for what.
Track action items and list resources. Keep artifacts and findings organized for easy reference.
Establish an After Action Report process. Learning from past incidents is critical. Review what went well and what needs improvement.
Proper documentation doesn’t just help during an incident, it also ensures continuous improvement.
Again, for a step-by-step guide on building out your own IR documentation, check out my article: How to Create Incident Response Documentation.
Runbooks
Just like Incident Response Documentation, Runbooks play just as crucial a part in preparation.
If you’re unfamiliar, Runbooks are step-by-step guides for common or identified threats in your environment, such as:
Threats that could occur in your environment
Threats that have already occurred in your environment
Emerging threats based on industry trends and news
How these runbooks get documented is not the important part. What is important is that there are clear, detailed guides readily available.
Make sure your Runbooks are comprehensive, accurate, and most importantly, actionable. In high-pressure situations, even a few seconds can make a difference.
Automation
Automations are the key to making your life easier.
Professionals with the eye to identify inefficiencies and implement solutions to streamline workflows are invaluable to any team.
Automations typically come in two flavors:
Automating Processes
Automating Actions
Automating Processes
This focuses on seamlessly integrating tools to reduce manual toil. Just think how much easier your life can be if you could:
Spin up IR documents
Create tickets
Add necessary stakeholders to a communication channel
And more…
All with a single click.
Automating Actions
This is where workflow orchestration tools like SOAR platforms or Jupyter Notebooks come into play. While there’s no right answer for the “best” tool, your focus should be on finding the right fit for your team.
Approach automation by:
Actively identifying opportunities from past incidents - these will be your low-hanging fruit
Considering response actions for critical scenarios (locking down machines, revoking SaaS access, resetting credentials, etc.)
Look for repetitive response actions - these will save the most time
There’s no one-size-fits-all approach to automation. Define your requirements as a team, choose a tech stack you’re comfortable with, and start building.
Practice
Table-Top Exercises (TTXs) are like your IR team’s dress rehearsal.
These fictional scenarios are meant to mimic real-life incidents and provide your team with an opportunity to see if your processes, tools, and teamwork are ready for when an actual incident happens.
To run an effective TTX:
Design scenarios that stress-test your IR pipeline from start to finish. While realism is helpful, focus on actions and decision making.
Assign roles so everyone has a defined responsibility.
As IR Lead, facilitate the incident and present challenges, adjust variables, and keep the team on their feet. Act as the “Dungeon Master.”
Practicing under controlled conditions ensures that your team is prepared, confident, and capable for when an incident inevitably does happen.
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The Incident
No matter how much you prep, the moment an actual incident occurs, you might still feel unprepared
Don’t let that get in your head, you’re more prepared than what you give yourself credit for.
But if it’s your first incident, having a clear idea of what to expect can make all the difference.
Here’s how a typical incident might unfold and the phases involved.
Detection
Every incident begins with a detection.
This can be triggered by a SIEM alert, a SaaS platform flagging suspicious activity, or even a report from another team member.
Regardless of the source, you’ll need to quickly alert the necessary stakeholders and spin up documentation immediately.
Get ready to respond, this is where the battle begins.
Investigation
Once a detection is escalated to an incident, your processes need to kick in.
This is where your reaction-based procedures come into play.
Some key actions to kick off an investigation are:
Assign roles. Everyone should know their responsibility from the get-go.
Quickly assess evidence you have in hand and decide which pieces need further digging.
Remain decisive. Not all leads will be productive, so focus on those that move the investigation forward.
As an IR Lead, stay high level. Assign relevant SMEs to where they can be successful, facilitate action items, and ensure information is being tied together in order to mitigate the threat.
The IR Second will work in tandem with you to ensure everything is well-documented and to support other stakeholders when needed.
It’s all about staying efficient and organized as the investigation progresses.
Mitigation
The primary goal in the Mitigation stage is to shut down the threat as quickly as possible.
After gathering your artifacts in the investigation phase, take action on them to ensure the malicious actor no longer has persistence in the environment.
During mitigation focus on taking action on artifacts. Utilize all of the information you’ve gathered to eliminate the threat.
In some cases, you may find value in being able to quickly create scripts to automate tasks. While pre-built scripts are ideal, they aren’t always plausible. Being comfortable with a scripting language will only benefit the investigation.
It’s also important to be familiar with the change process. You may uncover vulnerabilities or logic errors during the investigation that need immediate patching. As lead, it’s important to know the escalation process so you can involve the right stakeholders to address issues swiftly.
Mitigation is all about taking swift and decisive actions to get the job done.
Blast Radius
Once the threat has been mitigated, the next step is to fully understand the complete scope of the incident and its impact on your environment.
In this stage, you’ll need to think both like an attacker and defender simultaneously:
What would an attacker do next
How would they do it?
Where can you verify if this activity occurred or not?
This is when you’ll need technical skills and SMEs you can rely on and trust.
To assess the blast radius:
Deep dive and investigate all systems the attacker may have accessed
Identify potential areas of persistence
Track Indicators of Compromise (IoCs)
Piece together the full scope of damage done
The goal is to ensure no stone is left unturned.
Recovery
The Recovery phase is all about getting business operations back to normal.
It involves wrapping up any remaining loose ends such as restoring systems, drafting internal communications, engaging stakeholders for external communications, and documenting lessons learned for the After Action Report.
The goal is to ensure that the organization’s operations can continue without further disruption and that proper protocols are followed, especially when communicating with external parties.
After Action Report
The After Action Report (AAR), also known as the Retro, is one of the most important phases in the Incident Response process.
It’s your team’s opportunity to learn from the incident, identify what worked well, and pinpoint areas for improvement.
As IR Lead, it’s your responsibility to acknowledge wins, facilitate open discussion, formally identify areas for improvement, and to create/assign action items.
The AAR can help your team refine processes, tools, and communication to be better prepared for future incidents.
If you need help drafting up a template for your AAR, again, checkout my article, How to Create Incident Response Documentation for detailed guidance.
Moving Forward
Incident Response is all about preparation.
It’s about proactively putting in the work so that when the time comes, everything runs smoothly even though things have gone wrong.
As an individual, hone your technical skills and deepen your domain knowledge. Make sure that when your number is called, you’re ready to perform and contribute meaningfully to the team.
As a team, focus on developing and refining your tools, processes, and communication. A cohesive, well-coordinated team is key to handling any incident effectively and efficiently.
A good Incident Response team is made up of specialists who bring deep expertise in a domain, but also people who are willing to be generalists and are not afraid to perform any role when needed.
Identify your own strengths and double down on them while looking for gaps where you can compliment members of your own team.
If you’re interested in rounding out your knowledge, I’d suggest checking out one of my other related articles:
Securely Yours,
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