Refer to the exhibit.

The packet capture shown in the exhibit is indicative of DNS tunneling. This conclusion is drawn from the observation of the packets’ consistent size and frequency, which are directed to a specific destination IP address. Such a pattern is characteristic of DNS tunneling, where data is encapsulated within DNS queries and responses. This method is often used to bypass security controls or for data exfiltration, as it can blend with regular DNS traffic, making detection more challenging.

DNS tunneling can be used for legitimate purposes, such as when an organization’s remote workers need to access internal networks. However, it is also a technique commonly exploited by attackers to smuggle data out of a network or to communicate with command and control servers while evading detection.

References:

Cisco’s official training materials on Performing CyberOps Using Cisco Security Technologies (CBRCOR) provide insights into analyzing packet captures and identifying different types of network traffic, including malicious activities like DNS tunneling.

The Cisco CyberOps Associate Certification resources include detailed information on threat identification and response strategies pertinent to DNS tunneling.