Vigilantism Is a Poor Response to Cyberattack

By Bruce Schneier
Wired News
April 05, 2007

Last month Marine Gen. James Cartwright told the House Armed Services Committee that the best cyberdefense is a good offense.

As reported in Federal Computer Week, Cartwright said: "History teaches us that a purely defensive posture poses significant risks," and that if "we apply the principle of warfare to the cyberdomain, as we do to sea, air and land, we realize the defense of the nation is better served by capabilities enabling us to take the fight to our adversaries, when necessary, to deter actions detrimental to our interests."

The general isn't alone. In 2003, the entertainment industry tried to get a law passed (.pdf) giving it the right to attack any computer suspected of distributing copyright-protected material. And there probably isn't a sysadmin in the world who doesn't want to strike back at computers that are blindly and repeatedly attacking their networks.

Of course, the general is correct. But his reasoning illustrates perfectly why peacetime and wartime are different, and why generals don't make good police chiefs.

A cybersecurity policy that condones both active deterrence and retaliation -- without any judicial determination of wrongdoing -- is attractive, but it's wrongheaded, not least because it ignores the line between war, where those involved are permitted to determine when counterattack is required, and crime, where only impartial third parties (judges and juries) can impose punishment.

In warfare, the notion of counterattack is extremely powerful. Going after the enemy -- its positions, its supply lines, its factories, its infrastructure -- is an age-old military tactic. But in peacetime, we call it revenge, and consider it dangerous. Anyone accused of a crime deserves a fair trial. The accused has the right to defend himself, to face his accuser, to an attorney, and to be presumed innocent until proven guilty.

Both vigilante counterattacks, and pre-emptive attacks, fly in the face of these rights. They punish people who haven't been found guilty. It's the same whether it's an angry lynch mob stringing up a suspect, the Motion Picture Association of America disabling the computer of someone it believes made an illegal copy of a movie, or a corporate security officer launching a denial-of-service attack against someone he believes is targeting his company over the net.

In all of these cases, the attacker could be wrong. This has been true for lynch mobs, and on the internet it's even harder to know who's attacking you. Just because my computer looks like the source of an attack doesn't mean that it is. And even if it is, it might be a zombie controlled by yet another computer; I might be a victim, too. The goal of a government's legal system is justice; the goal of a vigilante is expediency.

I understand the frustrations of Cartwright, just as I do the frustrations of the entertainment industry, and the world's sysadmins. Justice in cyberspace can be difficult. It can be hard to figure out who is attacking you, and it can take a long time to make them stop. It can be even harder to prove anything in court. The international nature of many attacks exacerbates the problems; more and more cybercriminals are jurisdiction shopping: attacking from countries with ineffective computer crime laws, easily bribable police forces and no extradition treaties.

Revenge is appealingly straightforward, and treating the whole thing as a military problem is easier than working within the legal system.

But that doesn't make it right. In 1789, the Declaration of the Rights of Man and of the Citizen declared: "No person shall be accused, arrested, or imprisoned except in the cases and according to the forms prescribed by law. Any one soliciting, transmitting, executing, or causing to be executed any arbitrary order shall be punished."

I'm glad Cartwright thinks about offensive cyberwar; it's how generals are supposed to think. I even agree with Richard Clarke's threat of military-style reaction in the event of a cyberattack by a foreign country or a terrorist organization. But short of an act of war, we're far safer with a legal system that respects our rights.

earlier essay: How to Not Catch Terrorists
later essay: How Security Companies Sucker Us With Lemons
categories: Cyberwar and Cyberterrorism, Computer and Information Security, National Security Policy
back to Essays and Op Eds

Photo of Bruce Schneier by Per Ervland.

Schneier on Security is a personal website. Opinions expressed are not necessarily those of Co3 Systems, Inc..