What Steps Should Be Taken After a Suspected Phishing Incident?
An employee clicks a link on a Tuesday afternoon. By Thursday, an attacker has been quietly sitting in their inbox: reading emails, monitoring activity, and waiting. By the time anyone notices, the damage is done.
This isn’t a worst-case scenario. It’s a pattern we see regularly. Phishing attacks today don’t look like obvious scams. They look like routine emails from vendors, coworkers, banks, or cloud platforms your team already uses. That’s why many incidents aren’t discovered right away. Someone clicks a link, enters credentials, or opens an attachment before anything feels off.
If you suspect a phishing incident may have occurred, what happens next matters far more than how the email looked. A fast, structured response can prevent credential theft, limit business disruption, and stop a small mistake from turning into a costly security incident.
Below is a practical, step-by-step guide for what companies should do after a suspected phishing incident.
A Step-by-Step Response Guide
Step 1: Treat the Incident as Real Until Proven Otherwise
One of the most common mistakes we see is hesitation. Teams worry about overreacting or assume the issue is minor. In reality, phishing attacks are designed to create uncertainty, and waiting for confirmation gives attackers time to move.
If an employee reports a suspicious email, clicked link, or entered credentials, treat it as a real incident immediately. The goal is not to assign blame.
The goal is to reduce risk.
Step 2: Isolate the Affected Account or Device
Once a phishing incident is suspected, the affected user account and device should be isolated as quickly as possible. This typically includes:
- Disabling or locking the user account
- Forcing a password reset
- Revoking active login sessions
- Disconnecting the device from the network if malware is suspected
If the user entered credentials into a fake login page, assume those credentials are compromised. Even if nothing else appears wrong, attackers often test access quietly before taking action.
Step 3: Identify What Was Exposed or Accessed
After containment, the next step is understanding impact. Not all phishing incidents are equal. Key questions to answer include:
- Were credentials entered?
- Was multi-factor authentication enabled?
- Did the attacker successfully log in?
- Were emails or data accessed from the account?
This usually requires reviewing sign-in logs, mailbox activity, and audit trails across your business systems. Without visibility into these areas, it’s difficult to confidently say what was affected and what wasn’t.
Step 4: Remove the Threat and Close the Door
Once the scope is understood, the focus shifts to remediation. This may include:
- Removing malicious emails from other inboxes
- Blocking senders or domains
- Resetting additional credentials
- Cleaning or reimaging affected devices
One area that’s easy to overlook, and one that attackers count on: inbox rules and forwarding settings. Attackers routinely configure these in the background to maintain access even after passwords are reset. An inbox rule that quietly forwards all email to an external address can persist for weeks undetected. Identifying and removing these hidden changes is just as important as changing the password.
Until these changes are found and removed, the door isn’t fully closed.
Step 5: Notify the Right People
Depending on the situation, leadership and key stakeholders should be informed so there’s clarity around what occurred and how it was handled.
For businesses in regulated industries, external notification may also be required. Knowing when and how to notify customers, partners, or regulators isn’t always obvious, which is exactly why having an established incident response process matters before an incident occurs, not after.
Step 6: Understand Why It Worked
After the immediate issue is resolved, take a step back. Why did this phishing attempt succeed? The answer usually points to something specific: missing multi-factor authentication on a critical account, weak email filtering, limited employee awareness, or unclear reporting procedures.
The goal isn’t perfection. It’s understanding where the gaps are so they can be addressed before the next attempt. Most organizations use this step to make small, practical improvements: tightening email security settings, reinforcing reporting habits, or adding additional safeguards to high-value accounts.
Small changes at this stage significantly reduce the likelihood that a future attempt succeeds. If you’re not sure where your biggest gaps are, our Cybersecurity Ecosystem Assessment is a good place to start.
Why a Clear Incident Response Plan Matters
Phishing incidents rarely happen at a convenient time. They’re stressful, disruptive, and fast-moving, especially for growing businesses without dedicated security staff.
Steps 1 through 4 above are your active response: containment, investigation, and remediation. Steps 5 and 6 are about the full incident lifecycle, making sure the right people are informed and that you come out of the incident better prepared than you went in. Both phases matter, and having a plan for both is what separates a recoverable incident from a serious business disruption.
If reading through these steps made you realize you don’t have a clear answer for some of them, that’s exactly where we start. Connect with Louisville Geek to talk through incident response readiness and practical next steps.
About Louisville Geek
Louisville Geek helps growing businesses manage IT services and cybersecurity risk through practical, well-defined services. We support organizations that need predictable outcomes, clear communication, and security guidance that aligns with real-world operations. Our team helps companies prepare for incidents like phishing attacks and respond effectively when they occur.
