[There are] structural flaws in the online advertising system, which essentially failed to detect or prevent the abuse.

Discover-Tech advertisements have popped up on devices used by personnel in national-security-sensitive networks around the world, including those of various ministries of defence, armed forces, national cyber agencies, intergovernmental organisations and media outlets, Citizen Lab found.

The research unit said these advertisements have also appeared on networks used by the United Nations, NATO, the European Parliament, the European Commission and the Council of the European Union’s General Secretariat.

Government networks have also been targeted in at least 24 countries, including the United States, Italy, Denmark, Norway, Australia, Russia, Mexico and Israel itself. Networks of media organisations have also been targeted, mainly in Australia, Denmark and Sweden, according to Citizen Lab.

In a separate report, New York-based advertising security firm Confiant said its own investigations had found that some of Discover-Tech’s advertisements also appeared in critical networks used by the Pentagon, the United Nations International Atomic Energy Agency and the International Criminal Court.