What are Email Impersonation Attacks?
Email impersonation, also known as business email compromise (BEC) or CEO fraud, is a sophisticated scam where cybercriminals pose as senior executives within an organization to trick employees or partners into sending money or sensitive data. The attackers use spoofing techniques to make the malicious emails appear to come from a legitimate source.
I often see this attack vector used to target finance and HR departments. The fraudsters may impersonate a CEO or CFO and request urgent payments to vendors or money transfers. Similarly, they may pose as an HR manager asking for sensitive employee records like tax documents.
How Email Impersonation Attacks Work
Here is a typical workflow of an email impersonation attack:
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The attackers research the organization to identify senior executives and employees who handle finances or sensitive data.
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They spoof the executive’s email address so messages appear to come from their account.
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The impersonator sends convincing urgent requests to employees asking them to transfer funds or send sensitive data.
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If the targets fall for the scam, they end up sending money or data to the fraudsters.
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The attackers move quickly before the organization can detect the scam and reverse transactions.
Technical Methods Used
The attackers use various technical techniques to pull off a convincing spoof, such as:
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Email header manipulation – Altering the email header fields like the sender name and email address to impersonate someone.
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Lookalike domains – Registering domain names that closely resemble the company’s domain. Like ceo@companey-name.com instead of ceo@company-name.com.
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Email forwarding – Getting access to an internal user’s email account and forwarding messages to their own account before sending to the victim.
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Compromised accounts – Hacking into real employee accounts to send malicious emails directly.
Defense Strategies and Safeguards
Here are some key strategies and safeguards organizations can implement to protect against email impersonation attacks:
Employee Education and Training
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Conduct phishing simulations – Send simulated spear phishing emails to train employees to recognize and report suspicious emails.
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Teach email hygiene habits – Like hovering over sender names to inspect email addresses, scrutinizing urgency or secrecy, and verbally verifying unusual requests.
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Promote a diligent culture – Encourage speaking up about suspicious requests without fear of blame. Recognize those who catch phishing attempts.
Technical Safeguards
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Deploy DMARC – Domain-based Message Authentication, Reporting & Conformance helps prevent spoofing by verifying senders.
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Enable multi-factor authentication – Require a second form of authentication to access email, especially for accounts that handle financial transactions.
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Monitor for anomalies – Use email security tools to detect spikes in requests from executive accounts.
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Block high-risk file types – Block attachments like .exe, .js, .wsf which could contain malware.
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Limit external email forwarding – Disable automatic email forwarding to external domains to prevent data theft.
Process Changes
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Implement approval processes – Require secondary authorization for large transactions, data requests, or account changes.
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Verify requests – Train staff to visually validate financial and legal requests through a phone call or in-person meeting before acting.
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Limit data access – Only provide access to sensitive data on a need-to-know basis.
Real-World Examples of Email Impersonation
Here are two real-world examples of how attackers have used this technique:
CFO Impersonation to Steal $500,000
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A manufacturer’s CFO had his inbox compromised after clicking a phishing email.
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The attackers studied past emails to replicate his style.
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They spoofed his email address and urgently requested a wire transfer of $500,000 to a supplier account.
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Believing the request was legitimate, the accounts payable clerk initiated the transfer.
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By the time the scam was discovered, the funds were withdrawn and unavailable.
HR Impersonation to Steal Employee Data
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Scammers impersonated an HR manager at a healthcare company.
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They emailed a group of employees requesting updated W2 tax documents for urgent auditing.
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Several employees submitted their sensitive personal tax data through email.
- The attackers used this data to commit tax fraud and identity theft.
Conclusion
Defending against email impersonation requires a combination of security tools, user education, and smart processes. Organizations should train employees to recognize telltale signs of business email compromise attacks. By implementing DMARC, limiting high-risk email behaviors, and requiring secondary approvals, companies can shut down this lucrative attack vector. Staying vigilant and keeping security top of mind is key to protecting finances and data.
