The Pied Piper of Hamelin and cyberweapons

The legend of the Pied Piper of Hamelin has been used before as an allegory of real, tragic events. Here’s our take.

A look at the medieval legend as a cautionary tale of cyberweapon development

Contrary to popular opinion, fairy tales and folk legends were not invented as entertainment, but to teach children (and adults) important lessons in an easy-to-understand form. Since time immemorial, storytellers have woven cybersecurity tips into their tales, hoping to make the Internet (which they foresaw) a safer place. For example, the story of Little Red Riding Hood is a warning about MitM-type attacks, and Snow White foreshadows government-sponsored APT campaigns. The list goes on.

Unfortunately, humankind continues to repeat the same mistakes with manic persistence, ignoring the obvious lessons of fairy tales. Another striking example of this is the legend of the Pied Piper of Hamelin.

The Pied Piper of Hamelin

As is often the case with truly old tales, several versions have been handed down to us, all of them variations on the same basic theme. The essential plot goes something like this: The German town of Hamelin is infested with rats, which eat food supplies, attack people and domestic animals, and generally cause an almighty nuisance.

Unable to cope, the local authorities hire the services of a specialist in the form of a fancily dressed rat-catcher, who uses a magic pipe to lure the rats out of the town and into the nearby river, where they drown.

Afterward, the miserly mayor refuses to fulfill his side of the deal, and offers the rat-catcher, aka the Pied Piper, a far lower remuneration than was stipulated in the contract. The Piper says nothing. Instead, he takes his revenge by using his magic pipe again, this time to lure the children of Hamelin away in the same manner he did with the rats.

The ending depends on when the narrator lived and how optimistic they were (usually not very). The children are either drowned in the Weser River like the rats, are taken deep into the Koppenberg hills, or (in the most recent and least gloomy rendering) go beyond the hills to a distant land where they found a city.

The meaning behind the allegory

Curiously, the incident is given a precise date: June 26, 1284. The legend was first recorded in the town chronicles in 1375, after which it was rewritten and retold several times, acquiring extra details and embellishments in the process. Most of the details have clear politic or religious motivations. Some versions focus on the greed of the citizens of Hamelin; others openly demonize the figure of the Piper. We shall skip the medieval prejudices of the day and focus on the basic facts.

Attacks on Hamelin

The way we see it, Hamelin’s infrastructure comes under attack from unknown malicious actors. They literally devour material assets (grain) and information (legal documents), and threaten the health of local residents.

No detailed description of the attack has survived, but it’s likely that the attackers were referred to as “rats” because they used a Remote Access Tool (or Remote Access Trojan), both abbreviated as RAT. In general, such tools/Trojans can be used for all kinds of dirty work, because they give attackers full access to a victim’s system.

Hired specialist

At first, the town residents try a cat-based solution to protect their endpoints, but when that method proves ineffective, they engage a third-party expert who knows about a vulnerability in the attackers’ RAT. Targeting the vulnerability, he assembles a powerful cyberweapon to take remote control of the RAT operators’ computers, turning them into a kind of botnet. Having penetrated them all, the Piper successfully neutralizes the threat.

Targeting civilians

After the RAT attack is defeated, the authorities unwisely fail to honor their contract with the specialist. Most versions of the legend mention financial disagreements, but that is impossible to verify, of course. Whatever the case, it turns out the same vulnerability is present in the devices the town’s children use.

Regrettably, the tale does not provide technical details to explain why the same threat works against both RAT operators and ordinary members of the public. Let’s assume it was a vulnerability in something ubiquitous (for example, some popular application-level network protocol used for remote access to network resources).

Nor is it entirely clear why the so-called adults in the tale are not affected by the vulnerability. Perhaps the word “children” in the story refers not to underage users, but to a new generation of devices with a more recent operating system that developed a vulnerability after a botched update of the aforementioned protocol.

Either way, the finale is tragic: The Piper performs the same botnet trick — only not on RAT operators this time, but on the town’s youngsters.

The Pied Piper of Hamelin in modern times

The preceding is highly reminiscent of the story of the Shadow Brokers hacker group and the EternalBlue exploit leak, which led to the WannaCry outbreak as well as several other ransomware epidemics. If I had read the tale of the Pied Piper of Hamelin only after the EternalBlue leak, no doubt I would have taken it as a report, albeit an allegorical one, on that incident. The storyline is indeed identical: A government organization commissions the development of a powerful cyberweapon that is then unexpectedly used against the inhabitants of that same country.

We can attribute this remarkable coincidence to history’s habit of developing in a spiral. Obviously, sixteenth-century German infosec experts were already aware of the problem and tried to warn their descendants (us) of the dangers of government-sponsored cyberweapons programs, which one day might be turned against civilian users — with nasty consequences.