Hacking Nuclear Weapons

Until I saw the title of Andrew Futter’s Hacking the Bomb:  Cyber Threats and Nuclear Weapons in the new-books shelf of my university library, I had never given any thought to what the new threat of cyber warfare means to the old threat of nuclear war.  Quite a lot, it turns out. 

Futter is associate professor of history at the University of Leicester in the UK, and has gathered whatever public-domain information he could find on what the world’s major nuclear players—chiefly Russia, China, and the U. S.—are doing both to modernize their nuclear command and control systems to bring them into the cyber era, and to keep both state and non-state actors (e. g. terrorists) from doing what his title mentions—namely, hacking a nuclear weapon, as well as other meddlesome things that could affect a nuclear nation’s ability to respond to threats. 

The problem is a complicated one.  The worst-case scenario would be for a hacker to launch a live nuclear missile.  This almost happened in the 1983 film WarGames, back when cyberattacks were primitive attempts by hobbyists using phone-line modems.  Since then, of course, cyber warfare has matured.  Probably the most well-known case is the  Stuxnet attack on Iranian nuclear-material facilities (probably carried out by a U. S -Israeli team) discovered in 2010, and Russia’s 2015 crippling of Ukraine’s power grid by cyberweapons.  While there are no known instances in which a hacker has gained direct control of a nuclear weapon, that is only one side of the hacker coin—what Futter calls the enabling side.  Just as potentially dangerous from a strategic point of view is the disabling side:  the potential to interfere with a nation’s ability to launch a nuclear strike if needed.  Either kind of hacking could raise the possibility of nuclear war to unacceptable levels.

At the end of his book, Futter recommends three principles to guide those charged with maintaining control of nuclear weapons.  The problem is that two of the three principles he calls for run counter to the tendencies of modern computer networks and systems.  His three principles are (1) simplicity, (2) security, and (3) separation from conventional weapons systems. 

Security is perhaps the most important principle, and so far, judging by the fact that we have not seen an accidental detonation of a nuclear weapon up to now, those in charge of such weapons have done at least an adequate job of keeping that sort of accident from happening.  But anyone who has dealt with computer systems today, which means virtually everyone, knows that simplicity went out the window decades ago.  Time and again, Futter emphasizes that while the old weapons-control systems were basically hard-wired pieces of hardware that the average technician could understand and repair, any modern computer replacement will probably involve many levels of complexity in both hardware and software.  Nobody will have the same kind of synoptic grasp of the entire system that was possible with 1960s-type hardware, and Futter is concerned that what we can’t fully understand, we can’t fully control.

Everyone outside the military organizations charged with control of nuclear weapons is at the disadvantage of having to guess at what those organizations are doing along these lines.  One hopes that they are keeping the newer computer-control systems as simple as possible, consistent with modernization.  What is more likely to be followed than simplicity is the principle of separation—keeping a clear boundary between control systems for conventional weapons and systems controlling nuclear weapons.

Almost certainly, the nuclear-weapons control networks are “air-gapped,” meaning that there is no physical or intentional electromagnetic connection between the nuclear system and the outside world of the Internet.  This was true of the control system that Iran built for its uranium centrifuges, but despite their air-gap precaution, the developers of Stuxnet were able to bridge the gap, evidently through the carelessness of someone who brought in a USB flash drive containing the Stuxnet virus and inserted it into a machine connected to the centrifuges. 

Such air-gap breaches could still occur today.  And this is where the disabling part of the problem comes in. 

One problem with live nuclear weapons is that you never get to test the entire system from initiating the command to seeing the mushroom cloud form over the target.  So we never really know from direct experience if the entire system is going to work as planned in the highly undesirable event that the decision is made to use nuclear weapons. 

The entire edifice of nuclear strategy thus relies on faith that each major player’s system will work as intended.  Anything that undermines that faith—a message, say, from a hacker asking for money or a diplomatic favor, or else we will disable all your nuclear weapons in a way you can’t figure out—well, such an action would be highly destabilizing for the permanent standoff that exists among nuclear powers. 

Though it’s easy to ignore it, Russia and the U. S. are like two gunslingers out in front of a saloon, each covering the other with a loaded pistol.  Neither one will fire unless he is sure the other one is about to fire.  But if one gunman thought that in a few seconds, somebody was going to snatch his gun out of his hands, he might be tempted to fire first.  That’s how the threat of an effective disabling hack might lead to unacceptable chances of nuclear war. 

These rather dismal speculations may not rise to the top of your worry list for the day, but it’s good that someone has at least asked the questions, and has found that the adults in the room, namely the few military brass who are willing to talk on the public record, are trying to do something about them.  Still, it would be a shame if after all these decades of successfully avoiding nuclear war, we wound up fighting one because of a software error.

Sources:  Andrew Futter’s Hacking the Bomb:  Cyber Threats and Nuclear Weapons by Andrew Futter was published by Georgetown University Press in 2018.  I also referred to the Wikipedia article on Stuxnet.