Russia hack claims: What is the Cybersecurity and Infrastructure Security Agency (CISA)?

The federal Cybersecurity and Infrastructure Security Agency (CISA) recently reported widespread hacks involving government agencies and private businesses -- an apparent attack linked to Russia that may have gone unreported for up to nine months.

The hack compromised federal agencies and "critical infrastructure" in a sophisticated attack that was hard to detect and will be difficult to undo, CISA announced in an unusual warning message Thursday. 

Established under President Trump in 2018, CISA operates under the Department of Homeland Security (DHS) oversight. 

Its activities are a continuation of the National Protection and Programs Directorate (NPPD). CISA was established when Trump signed the Cybersecurity and Infrastructure Security Agency Act. 

CISA’s mission is to "build the national capacity to defend against cyber attacks" and to work "with the federal government to provide cybersecurity tools, incident response services and assessment capabilities to safeguard the .gov networks that support the essential operations of partner departments and agencies."

CISA is an independent arm under DHS, on par with the Secret Service or Federal Emergency Management Agency (FEMA).