The First 24 Hours After a Cyber Incident: What Should Actually Happen
When a cyber incident is detected, the first instinct is to act fast.
Block access.
Shut systems down.
Restore operations.
Speed matters—but unplanned speed causes damage.
What happens in the first 24 hours often decides whether an incident is fully resolved or quietly returns later.
Hour 0–6: Confirm and Contain Without Panic
The moment an incident is identified, pressure builds across teams. Leadership wants clarity, business teams want systems back, and security teams want to isolate the threat.
This is where discipline matters most.
What should happen:
- Confirm the incident using multiple data points
- Isolate affected systems, not the entire environment
- Preserve logs and volatile data before rebooting or patching
- Limit unnecessary access changes to avoid contaminating evidence
Common mistake:
Treating every alert as a confirmed breach—or wiping systems before understanding what occurred.
Once volatile data is lost, the opportunity to understand the attack is gone.
Hour 6–12: Start Understanding What Actually Happened
After containment begins, the focus should shift from stopping activity to reconstructing events.
Key questions include:
- How did the attacker gain initial access?
- Which systems show confirmed activity?
- Is there evidence of lateral movement?
- Are credentials involved?
This step requires correlating logs, endpoint data, identity activity, and network traffic—not just reviewing alerts.
Skipping this phase often leads to false confidence.
Hour 12–24: Assess Impact and Guide Decisions
By the end of the first day, leadership decisions must be grounded in facts.
This is the stage where organizations need answers to:
- Was sensitive data accessed or exfiltrated?
- Is it safe to restore systems?
- Do we need to notify regulators, customers, or partners?
- Could the attacker still have access?
Without evidence-backed findings, decisions are based on assumptions—and assumptions don’t stand up to audits or legal review.
Why the First 24 Hours Are So Often Mishandled
Most organizations have strong detection capabilities. Fewer are prepared for post-detection reality.
Common gaps include:
- No defined incident response workflow
- Lack of forensic readiness
- Unclear coordination between IT, security, and leadership
- Tools designed for alerts, not investigation
This leads to rushed fixes instead of informed recovery.
Preparation Makes the Difference
Organizations that manage incidents well are not calmer by chance—they are prepared.
Preparation includes:
- A documented incident response process
- Clear escalation and decision paths
- Evidence preservation procedures
- Access to forensic and incident response expertise
Preparation turns chaos into coordination.
The first 24 hours after a cyber incident are not about reacting faster.
They’re about reacting correctly.
Detection tells you something went wrong.
Investigation and response tell you what happened and what to do next.
AtmosSecure, the cybersecurity arm of Network Techlab, is building dedicated Digital Forensics and Incident Response (DFIR) capabilities to help organizations navigate these critical early hours with clarity and confidence.
When incidents demand answers, evidence matters.
Learn more about upcoming DFIR capabilities from AtmosSecure.
