What does an atypical spike in total outbound DNS traffic from a network-attached device suggest?

An atypical spike in total outbound DNS traffic from a network-attached device often indicates that the device is attempting to connect with an unusually high number of external domains or is reaching out to domains that are not regularly accessed. This behavior is commonly associated with data exfiltration, where sensitive information is being sent out of the network without authorization.

When an attacker gains access to a network or a specific device, they may utilize DNS queries to send stolen data to external servers. Since DNS requests need to reach external domains for this communication to occur, a sudden increase in outbound DNS queries can suggest that data is being covertly transferred away from the organization.

Such a spike would be unusual in the context of typical network behavior, suggesting that the increased DNS activity is not due to normal operations like browsing or legitimate cloud-based services, but instead indicates potentially malicious activity aimed at exfiltrating data.

While increased network activity could also cause spikes in DNS traffic, it doesn't specifically point to the unauthorized nature of the traffic as data exfiltration does. Similarly, while malware infections can lead to altered traffic patterns, the specific spike in DNS traffic directly points to data being sent out, which is why the focus on data exfiltration is most accurate here