A Denial Of Clue attack is a strategic disinformation attack that manifests as a Resource Consumption Attack (RCA).
Totalitarian or nationalist targets are deeply concerned with the appearance of infallibility – governments do not want to be perceived as inactive in the face of a threat, or to respond ineffectively to a threat. In a Denial Of Clue attack, the attacker merely threatens a plausible threat-vector, leaks it to the media or marketplace of ideas, then never attacks that threat-vector. Done correctly, the target will expend resources and make itself look fallible in its attempt to appear infallible.
During the Global War On Terror, the government has inflicted Denial Of Clue attacks on itself several times. Usually this is in the form of one agency hypothesizing that another agency may be subjected to a certain type of attack, which then triggers investigation and media coverage, and suddenly the hypothetical target is expending resources to protect against an attack that never materializes.
Denial Of Clue attacks can be used in combination with one-off attacks, to create a Death Of A Thousand Cuts scenario, in which the target is constantly chasing the last threat model, but is being bombarded with plausible yet spurious threats in a Denial Of Clue, bolstered by one-off pinprick attacks designed to overload their incident response capability.
Probably the most famous instance of a Denial Of Clue attack was when Idaho National Labs hypothesized an “AURORA” attack, in which power-phasing could be used to destroy systems (this actually became the core of Stuxnet) Immediately a great deal of effort was expended over the question of whether or not AURORA attacks could be launched against the US power grid. To date, no such attacks have happened. If there was a credible spoof indicating that such attacks were being planned, coupled with a normal or kinetically induced electrical failure, it might be possible to get the Department of Homeland Security to punch itself stupid trying to worry about deflecting an attack that never materializes. Alternatively, get them worried about a cyberattack and go kinetic. Or, get them worried about a kinetic attack and go cyber.
Aurora Attacks (Wikipedia)