What agency is responsible for cyber defense within the DoD?

The Defense Information Systems Agency (DISA) is tasked with ensuring the cyber defense of the Department of Defense. DISA plays a critical role in providing secure, reliable information technology and communications support to the military and other defense entities. This includes oversight of the cybersecurity posture for DoD networks and systems, ensuring they are resilient against various cyber threats.

DISA's functions encompass both defensive measures and the implementation of cybersecurity policies across the DoD. By managing the secure operation of IT networks, DISA helps maintain the integrity and security of sensitive defense information.

While other agencies listed have significant roles in cybersecurity, they operate in different capacities or contexts. For instance, the National Security Agency (NSA) focuses more on intelligence and national security, including cyber intelligence operations. The Cybersecurity and Infrastructure Security Agency (CISA) works across federal and state levels on cyber and infrastructure security but is not exclusively tasked with the DoD's cyber defense. The Department of Defense Cybersecurity Division is integral to broader defense strategic oversight but functions within the larger framework that DISA operates. Thus, DISA is the primary agency responsible for cyber defense within the DoD.