Which of the following is least likely to be a function of a Cisco ESA? (Select the best answer.)

A.
protecting against phishing

B.
protecting against spam

C.
protecting against a DDoS attacks

D.
protecting against malicious files

Explanation:
Protecting against a Distributed Denial of Service (DDoS) attack is least likely to be a function of a Cisco Email
Security Appliance (ESA). A DDoS attack is a security threat that attacks availability by overwhelming a device
or network with traffic from many varying sources. An ESA is designed to protect against email threats, such as
malware attachments, phishing scams, and spam.
The Cisco Context Adaptive Scanning Engine (CASE) on an ESA is a technology that is intended to detect
email threats as they are received. CASE checks the reputation of email senders, scans the content of email
messages, and analyzes the construction of email messages. As part of this process, CASE submits the email
sender to the Cisco SenderBase Network, which contains data on hundreds of thousands of email networks.
The sender is assigned a score based on this information. The content of the email messaging is scanned
because it could contain language, links, or a call to action that is indicative of a phishing scam.

Cisco: Secure solutions for advanced email threats (PDF)
Cisco: User Guide for AsyncOS 11.0 for Cisco Email Security Appliances: Context Adaptive Scanning Engine