Incident Response: What to Do When Phishing or BEC Succeeds

Despite the best training and technical controls, phishing and BEC attacks sometimes succeed. What happens in the minutes and hours afterward often determines whether the incident is a contained inconvenience or a significant financial and reputational loss. Innovo Networks outlines the response steps that matter most.

The First Hour Matters Most

Speed is critical, particularly for BEC incidents involving fraudulent financial transfers. Funds moved through fraudulent wire transfers can sometimes be recovered if banks are notified within hours, but that window closes quickly as money moves through additional accounts.

Immediate Steps for Credential Compromise

• Reset affected credentials immediately and revoke active sessions, not just the password, since an attacker with a valid session token may retain access even after a password change.
• Review recent account activity for signs of what the attacker accessed, forwarded, or changed — including mail forwarding rules, which are a common technique used to maintain visibility into a compromised inbox even after password resets.
• Check for lateral movement — whether the compromised account was used to access other systems, send further phishing emails internally, or escalate privileges.

Immediate Steps for BEC-Related Financial Fraud

• Contact your bank immediately to attempt to freeze or recall a fraudulent transfer — every hour of delay reduces the likelihood of recovery.
• Notify relevant law enforcement and financial fraud reporting bodies, since many jurisdictions have specific channels for reporting this kind of fraud quickly.
• Preserve all related communications — the original fraudulent email, headers, and any related correspondence — as evidence for both investigation and potential recovery efforts.

Communicating Internally and Externally

• Notify affected stakeholders promptly, including anyone who may have received further phishing attempts from a compromised account.
• Avoid public overreaction, but don't downplay the incident internally — employees should understand what happened in enough detail to remain alert for follow-on attempts.
• Assess legal and regulatory notification obligations early, particularly if customer or partner data may have been exposed.

Investigating Root Cause

Once immediate containment is complete, a thorough investigation should determine how the attack succeeded — a technical gap, a process failure, a training gap — so the same vulnerability doesn't lead to a repeat incident. This should include reviewing why the specific email or request bypassed existing controls, and whether verification processes were followed, bypassed, or simply didn't exist for that scenario.

Building Resilience for Next Time

• Update training and simulations to reflect the specific tactics used in the successful attack.
• Close identified process gaps, particularly around financial approval and verification steps.
• Review technical controls — email authentication, monitoring rules, access permissions — for gaps the incident revealed.

Innovo Networks' Approach

We help organizations build and rehearse incident response plans specifically for phishing and BEC scenarios — not generic breach response plans, but playbooks addressing the specific urgency of financial fraud recovery and account compromise containment. When an attack succeeds despite your best defenses, a fast, well-rehearsed response is often what determines whether the story ends in a recovered transfer or a costly loss.