Firmware operates at a lower level than the operating system. It's the software embedded in hardware components like the BIOS/UEFI, network cards, hard drives, etc. If a vulnerability exists in the firmware, an exploit can run before the operating system even boots or can operate outside of the OS's control.

Sender Policy Framework allows a domain owner to specify which mail servers are authorized to send email on behalf of the domain by publishing this information in a DNS record. Receiving mail servers check the sending server's IP address against the domain's SPF record to verify that the email originates from an approved source. This helps prevent spoofing and reduces the likelihood that legitimate emails will be flagged as spam.

The employee notices that the links in the email do not correspond to the company's official URLs, indicating that this is likely a social engineering attack. Social engineering involves manipulating individuals into divulging confidential information or performing actions that may compromise security. Phishing emails, like the one described, often contain fraudulent links to trick the recipient into providing sensitive information or downloading malware.
* Business email refers to business email compromise (BEC), which typically involves impersonating a high-level executive to defraud the company.
* Unsecured network is unrelated to the email content.
* Default credentials do not apply here, as the issue is with suspicious links, not login credentials.

A tabletop exercise is a simulated event in which the incident response team and other stakeholders walk through their roles and decision-making processes to evaluate readiness and improve response plans.