In a world of documentary gadflies, navel gazers and agenda-pushers, Alex Gibney has earned a “teller of hard truths” reputation.

If you’re in the know, or simply want to be, he is documentary cinema’s E.F. Hutton. When Gibney talks, about the rapacious nitwits of Enron, bout Lance Armstrong’s fall from grace or the excesses of Hunter S. Thompson, Steve Jobs, Wikileaks and Julian Assange or the United States government, people listen. Or should.

With “Zero Days,” the Oscar winner turns his camera, his attention and ours towards the Stuxnet virus and its implications for the future of cyber warfare. He’s made a “genie out of the bottle” investigative mystery about that online attack on Iran’s nuclear weapons program.

And if he never quite makes the case that we’ve paved the way for an online apocalypse, he’s still able to chill us over what has happened, what could happen and what we might want to think about doing to prevent a worst case scenario cyber war.

Because, you know, we’ve all seen “The Terminator.”

Gibney spends over an hour of “Zero Days” retracing the online security community’s search for the origins of this virus, discovered in 2010, that to a one they describe as “sophisticated” and dangerously capable of something beyond slowing down your computer. Stuxnet– an amalgam of a couple of random word-like letter combination discovered in the virus’s code — could create actual “physical destruction” of any gadget run or monitored by computers.

That could be pipelines or power grids or, in the case of Iran, centrifuges used in the processing/isolation of uranium to make nuclear bombs. Stuxnet could sneak in with “zero days” warning, hide itself within a system, absorb the normal operating parameters of that system and mask its activities as it caused say, the water pump in a nuclear reaction to break, triggering something awful. It requires no human intervention to spread, no blunders at the keyboard to infect the unwitting.

Two early “heroes” of this tale work for the well-known cyber-security company Symanetc, which is probably running the anti-virus on the device on which you’re reading this review. Two code-crunchers named Eric Chien and Liam O’Murchu dove into the vast array of code in the virus and started turning up clues.

Others, from Germany (Ralph Langer), Israel and disguised insiders from the U.S. and Israeli intelligence community, talk on camera about what they can and cannot talk about, the “national security” implications of what happened leading up to 2010, and what the blowback from that was and could be in the future.

It’s fascinating in the unraveling, as Gibney the narrator announces he’s progressively more and more irked at the runaround he’s getting, making him ever more determined to get to the bottom of this “crime” or “intelligence coup” that no one will own up to.

His profane NSA insider curses the blunders that put this virus “out there” for friends and enemies to see and study.

“Because they were in a hurry, they opened Pandora’s Box.”

A former member of Israel’s Mossad secret police talks about the context of world events and Israeli politics that fed into all this.

And the ever-outspoken former counter-terrorism chief Richard C. Clarke shows up in the third act to talk about implications and provides the “actions to be taken” step in this rhetorical exercise in cinematic persuasion.

It’s quite hard to jazz up a story about computers, code, viruses and the people who make them and foil them. Gibney doesn’t totally crack that anti-cinematic nut at the heart of “Zero Days.”

But as with every other film in his fast-growing canon, Gibney wields his authoritative research and storytelling skills like a scalpel, getting at a subject we aren’t talking about with blunt facts and informed, cautionary speculation.

And if you weren’t concerned about this latest threat to privacy, security and our increasingly interconnected world before seeing “Zero Days,” you will be by the closing credits.

MPAA Rating:PG-13 for some strong language

Cast: Richard C. Clarke, Eric Chien, Ralph Langer, General Michael Hayden, Liam O’Murchu, David Sanger, Gary Samore
Credits: Written and directed by Alex Gibney.. A Magnolia release.

Running time: 1:55