Plausible Denial
A reference on the world's intelligence services and what they have done.
Plausible Denial is an editorial reference site on the world's intelligence services. The site is organised around three indexes: countries (the national intelligence apparatus, by state), agencies (every service on the site, in alphabetical order), and dossiers (operations, scandals, and themes that cross agency or country lines).
Each agency entry carries a structured reference apparatus — founding date and statutory citation, jurisdiction, parent ministry, headquarters, predecessor services, links to official channels — and a body that walks through role, history, and notable operations. Operations are categorised confirmed, alleged, or disputed, footnoted to primary documents and the most defensible secondary record. The full sourcing standard is set out on the methodology page.
Central Intelligence Agency (CIA)
The principal foreign human-intelligence and covert-action service of the United States, created in 1947 as successor to the wartime Office of Strategic Services.
National Security Agency (NSA)
The signals-intelligence and information-security agency of the United States, established in 1952 by classified executive order and disclosed publicly only in 1957.
Federal Bureau of Investigation (FBI)
The principal domestic intelligence and federal law-enforcement agency of the United States, with statutory authority for counterintelligence, counter-terrorism, and federal criminal investigation.
Secret Intelligence Service (SIS (MI6))
The United Kingdom's foreign human-intelligence service, popularly known as MI6, established in 1909 as the foreign section of the Secret Service Bureau.
Security Service (MI5)
The United Kingdom's domestic security service, popularly known as MI5, responsible for counter-intelligence, counter-terrorism, and protection of national security inside the United Kingdom.
Government Communications Headquarters (GCHQ)
The United Kingdom's signals-intelligence, cryptography, and cyber-security agency, with origins in the wartime Government Code and Cypher School at Bletchley Park.
Mossad
Israel's foreign intelligence service — formally the Institute for Intelligence and Special Operations — reporting directly to the Prime Minister and responsible for foreign HUMINT, covert action, and counter-terrorism abroad.
Federal Security Service (FSB)
The Russian Federation's principal domestic security and counter-intelligence service, successor to the KGB and headquartered at the Lubyanka in Moscow.
NotPetya
The 27 June 2017 destructive cyber operation that began as a Ukrainian-targeted attack via a supply-chain compromise of the M.E.Doc accounting software and spread globally within hours, weaponising the leaked NSA EternalBlue SMB exploit for lateral movement. The operation is the most economically destructive cyber attack in history — approximately $10 billion in damages worldwide — and was attributed to GRU Unit 74455 (Sandworm) by the Five Eyes intelligence partners in February 2018. Indicted as part of the United States Department of Justice's 19 October 2020 charging of six GRU officers.
The Church Committee
The Senate Select Committee to Study Governmental Operations with Respect to Intelligence Activities, chaired by Senator Frank Church of Idaho, established by S. Res. 21 on 27 January 1975. Across approximately fifteen months of investigation the Committee produced the public-record reconstruction of US intelligence-service activity in the post-1947 period, documented across an Interim Report on Alleged Assassination Plots (November 1975) and a Final Report in six books (April 1976). The investigation produced the foundational architecture of contemporary US intelligence oversight: the Senate Select Committee on Intelligence, the House Permanent Select Committee on Intelligence, the Foreign Intelligence Surveillance Act of 1978, and the successive Executive Orders governing US intelligence activities.
The Family Jewels
The 693-page internal Central Intelligence Agency compendium produced in May–June 1973 in response to Director James Schlesinger's directive to CIA personnel to report any activities they believed to lie outside the Agency's statutory authority. The document became the principal internal-disclosure base for the Rockefeller Commission and Senate [Church Committee](/dossiers/church-committee) investigations of 1975–76, and was declassified by CIA on 25 June 2007.
