Cyber threats can disrupt essential services, expose sensitive information, and undermine military readiness. In the United States, responsibility for defending against these risks is distributed across federal agencies, each with distinct authorities and capabilities.
The Cybersecurity agencies in the United States include CISA, the NSA, U.S. Cyber Command, and the FBI, alongside other departments with specialized roles. Their coordination supports national defense, incident response, and protection of critical infrastructure.
How U.S. Cybersecurity Agencies Protect National Security
Cybersecurity agencies in the United States protect national security by helping prevent, detect, and respond to threats against government networks, military systems, and critical infrastructure. These threats may come from foreign governments, criminal groups, or other malicious actors, and can disrupt essential services or expose sensitive information.
Their responsibilities span intelligence gathering, cyber defense, law enforcement, and incident coordination. Agencies identify risks, share threat information with relevant organizations, investigate cybercrime, and support efforts to contain attacks and restore affected systems. Their authorities differ, so each agency acts within its specific legal mandate.
This work also involves cooperation with private companies and state, local, tribal, and territorial governments, many of which operate or support critical services. Sharing timely information and practical guidance can help organizations strengthen defenses and manage incidents, while protecting sensitive information and respecting applicable laws.
Together, these activities reduce the likelihood that cyber incidents will undermine government operations, military readiness, or public safety. They also help national leaders understand evolving threats and coordinate an effective response when an incident has broader security implications.
Cybersecurity and Infrastructure Security Agency (CISA)
The Cybersecurity and Infrastructure Security Agency (CISA), part of the U.S. Department of Homeland Security, leads federal efforts to strengthen cybersecurity and protect critical infrastructure. It works with government and private-sector partners to reduce risks across systems and services that support national security and daily life.
CISA helps organizations prepare for, identify, and respond to cyber incidents. Its resources include vulnerability information, security guidance, incident-response support, and tools for improving cyber resilience. The agency also shares threat information to help organizations make informed defensive decisions.
CISA provides support to state, local, tribal, and territorial governments, which may have limited cybersecurity resources. This assistance can include assessments, training, technical guidance, and coordination during incidents.
Its work can involve:
- Advising organizations on cyber risks and protective measures
- Helping coordinate responses to significant incidents
- Supporting collaboration across government and critical-infrastructure sectors
Cyber defense, incident response, and risk reduction
CISA helps protect federal civilian networks and the wider U.S. cyber ecosystem by sharing threat information, publishing security guidance, and supporting organizations as they strengthen defenses. Its services include vulnerability assessments and tools that help agencies and other eligible partners identify weaknesses and reduce exposure.
When a cyber incident occurs, CISA coordinates technical assistance, helps affected organizations understand and contain threats, and shares information that can limit further harm. Its response work is conducted alongside partners, including federal agencies, and does not replace law enforcement investigations or an organization’s responsibility to manage its own systems.
For risk reduction, CISA issues alerts and recommendations on topics such as known exploited vulnerabilities, secure configurations, and emerging threats. These resources help organizations prioritize practical steps, including patching vulnerable software, improving access controls, and preparing incident-response plans. As one of the cybersecurity agencies in the United States, CISA focuses on prevention, preparedness, and coordinated support.
Support for state, local, tribal, and territorial governments
CISA helps state, local, tribal, and territorial (SLTT) governments strengthen cybersecurity and prepare for incidents. Its services are generally voluntary and are intended to complement—not replace—each government’s own security responsibilities and authorities.
Depending on eligibility and availability, CISA may provide:
- Cybersecurity assessments that identify vulnerabilities and recommend ways to reduce risk.
- Technical guidance, threat information, and incident-response assistance.
- Tools and services to help organizations monitor networks and improve resilience.
CISA also works with SLTT partners through regional personnel and information-sharing channels. These connections can help officials understand relevant threats, coordinate with federal responders, and access practical guidance during cyber incidents.
Because local needs and available resources vary, the support offered may differ by organization and situation. Through these partnerships, Cybersecurity agencies in the United States help extend defensive resources to public services such as emergency management, education, and local government operations.
National Security Agency (NSA) and U.S. Cyber Command
The National Security Agency (NSA) and U.S. Cyber Command have distinct but closely connected responsibilities in national cyber defense. The NSA is a Department of Defense intelligence agency whose cybersecurity mission includes protecting national security systems and helping defend the U.S. defense industrial base against sophisticated cyber threats.
The NSA also conducts foreign signals intelligence, collecting and analyzing communications and other signals abroad to inform national security decisions. Its cybersecurity work includes developing guidance and sharing threat information with authorized government and private-sector partners.
U.S. Cyber Command is a unified combatant command responsible for military operations in and through cyberspace. It directs activities that help defend Department of Defense networks and may conduct operations to support U.S. military objectives, under applicable authorities and oversight.
Although the organizations share a director, they remain separate entities with different missions and authorities. Within the broader network of Cybersecurity agencies in the United States, they focus on intelligence, defense-related systems, and military cyberspace operations rather than serving as the general public’s primary point of contact for cyber incidents.
NSA’s foreign signals intelligence and cybersecurity mission
The National Security Agency (NSA) collects and analyzes foreign signals intelligence (SIGINT) to inform U.S. national security decisions. This work focuses on communications and other signals relevant to foreign governments, organizations, and threats, and is conducted under applicable legal authorities and oversight.
The NSA also supports cybersecurity by developing insights into foreign cyber threats and helping protect U.S. national security systems. Its expertise can inform government defenses against sophisticated activity targeting sensitive networks and communications.
In coordination with other federal partners, the NSA shares relevant threat information and technical guidance to strengthen cyber defense. Its foreign intelligence mission is distinct from domestic law enforcement: the agency is not the primary point of contact for individuals or businesses reporting cybercrime.
U.S. Cyber Command’s military cyberspace operations
U.S. Cyber Command (USCYBERCOM) conducts military operations in and through cyberspace to support U.S. defense objectives. Its responsibilities include defending Department of Defense networks and, when authorized, conducting operations designed to disrupt or counter threats to national security.
The command works with military services and other government partners to plan and execute cyberspace operations. These may include defensive activities that protect military systems and offensive operations against adversary capabilities. Specific operational details are often classified.
USCYBERCOM’s missions are distinct from the National Security Agency’s intelligence and cybersecurity work, although the organizations share leadership and cooperate closely. Their coordination helps connect intelligence insights with military planning while maintaining separate legal authorities and responsibilities.
As part of the broader network of cybersecurity agencies in the United States, USCYBERCOM focuses on military cyberspace operations rather than general civilian cyber incident response. Its activities are conducted under applicable law and direction from national leadership.
Federal Bureau of Investigation (FBI) Cyber Division
The FBI Cyber Division investigates cybercrime that crosses state or national borders, threatens critical infrastructure, or involves sophisticated criminal and state-linked actors. Its work includes identifying intrusions, collecting evidence, and pursuing those responsible under federal law.
The division works with FBI field offices and international partners to investigate ransomware, computer intrusions, online fraud, and other cyber-enabled offenses. When appropriate, the FBI may use legal authorities to disrupt criminal infrastructure, such as malicious servers or stolen-data marketplaces.
Victims can report cyber incidents to the FBI’s Internet Crime Complaint Center (IC3) or contact a local FBI field office. Prompt reporting can help investigators preserve evidence, identify links between cases, and share relevant threat information with affected organizations.
Within the network of cybersecurity agencies in the United States, the FBI’s distinctive function is federal law enforcement. It investigates and attributes cybercrime; it does not replace organizations’ own incident-response teams or provide general cybersecurity monitoring.
Department of Homeland Security and the Federal Cybersecurity Mission
The Department of Homeland Security (DHS) leads much of the federal government’s civilian cybersecurity work. Its mission includes reducing cyber risk to federal networks and helping protect critical infrastructure, such as energy, transportation, and communications systems.
Within DHS, the Cybersecurity and Infrastructure Security Agency (CISA) serves as the lead civilian agency for coordinating cyber defense and sharing threat information. CISA works with federal agencies, private organizations, and other partners to identify vulnerabilities, strengthen resilience, and respond to cyber incidents.
DHS also supports implementation of federal cybersecurity policies and helps agencies improve the security of their information systems. Its work complements the responsibilities of law enforcement and intelligence organizations, which investigate cybercrime and address foreign threats.
Because many essential services are operated outside the federal government, DHS’s mission depends on collaboration across sectors and levels of government. This partnership-oriented approach helps the United States prepare for, withstand, and recover from cyber disruptions.
Other Federal Agencies with Cybersecurity Responsibilities
Other federal bodies contribute specialized expertise to cybersecurity agencies in the United States. The Department of Energy helps protect energy-sector infrastructure and supports research on cyber risks to electricity and other critical systems. The Environmental Protection Agency works with water and wastewater utilities on cybersecurity preparedness and resilience.
The Department of the Treasury safeguards its own systems and helps address cyber threats affecting financial institutions and markets. Its Office of the Comptroller of the Currency supervises federally chartered banks, while the Financial Crimes Enforcement Network supports efforts to detect illicit financial activity, including cyber-enabled crime.
The Department of Defense also protects its networks and technology supply chains, working with military components and contractors under applicable security requirements. The Federal Trade Commission addresses certain cybersecurity and data-security matters through its consumer-protection and competition authorities. These agencies’ responsibilities vary by sector and statute, so their roles complement rather than replace those of CISA, the FBI, and other national cyber authorities.
How U.S. Cybersecurity Agencies Coordinate During Incidents
During a cyber incident, agencies coordinate according to their authorities and the nature of the threat. The affected organization should report promptly through appropriate channels, enabling federal partners to assess the incident, share relevant information, and determine which teams can assist.
CISA coordinates federal civilian cybersecurity support and helps affected organizations reduce risk, manage response, and restore operations. The FBI investigates cybercrime and gathers evidence, while the NSA and U.S. Cyber Command may contribute within their distinct intelligence and military authorities.
Coordination can include sharing indicators of compromise, technical analysis, and threat warnings with government and private-sector partners. For incidents involving critical infrastructure or multiple jurisdictions, agencies may work with state, local, tribal, and territorial authorities to align response efforts.
The Cybersecurity agencies in the United States do not operate as a single response team; responsibilities depend on the incident and applicable law. Reporting through the relevant agency’s established channels helps direct information to the appropriate responders.
Choosing the Right U.S. Cybersecurity Agency to Contact
For cyber incidents affecting a federal civilian agency’s systems, contact the agency’s security operations center and follow its reporting procedures. CISA also accepts reports of cyber incidents and can provide technical assistance, particularly when an organization needs help reducing risk or responding to an attack.
Report suspected cybercrime, ransomware, online fraud, or threats to the FBI through a local field office or the FBI’s online reporting channels. Organizations should preserve relevant evidence and avoid delaying notification while determining the full extent of an incident.
For suspected foreign intelligence activity or threats involving national security, use appropriate federal law-enforcement or intelligence reporting channels; NSA is not a general public incident-reporting service. Military cyber operations are handled through U.S. Cyber Command and the Department of Defense’s established channels.
State, local, tribal, and territorial governments can seek support from CISA and their state or territorial cybersecurity authorities. In urgent situations, contact emergency services when there is an immediate threat to life or physical safety. The right agency depends on the incident’s target, impact, and suspected criminal or national-security connection.