In response to suspicious communications originating from executive accounts, the organization ' s response team...

The EC-Council Incident Handler (ECIH) curriculum identifies email spoofing as a common technique in business email compromise (BEC) attacks. Attackers exploit weak or misconfigured DNS-based email authentication controls to forge sender identities.

Sender Policy Framework (SPF), DomainKeys Identified Mail (DKIM), and Domain-based Message Authentication, Reporting, and Conformance (DMARC) are DNS-based mechanisms that validate legitimate email senders and prevent spoofing. Proper configuration ensures that receiving mail servers can verify message authenticity and reject forged communications.

In this scenario, unsecured DNS entries enabled identity relay spoofing. Strengthening SPF, DKIM, and DMARC directly addresses the root cause and prevents recurring forged message injections. This is a clear eradication measure aimed at eliminating the exploitation pathway.

Options A and B relate to review and analysis phases. Option C supports threat intelligence sharing but does not remediate the internal DNS weakness.

Therefore, strengthening SPF, DKIM, and DMARC configurations is the appropriate eradication strategy.