A Vigilante Hacker Took Down North Korea’s Internet. Now He’s Taking Off His Mask

A little over two years have passed since the online vigilante who would call himself P4x fired the first shot in his own one-man cyberwar. Working alone in his coastal Florida home in late January of 2022, wearing slippers and pajama pants and periodically munching on Takis corn snacks, he spun up a set of custom-built programs on his laptop and a collection of cloud-based servers that intermittently tore offline every publicly visible website in North Korea and would ultimately keep them down for more than a week.

P4x’s real identity, revealed here for the first time, is Alejandro Caceres, a 38-year-old Colombian-American cybersecurity entrepreneur with hacker tattoos on both arms, unruly dark brown hair, a very high tolerance for risk, and a very personal grudge. Like many other US hackers and security researchers, Caceres had been personally targeted by North Korean spies who aimed to steal his intrusion tools. He had detailed that targeting to the FBI but received no real government support. So he decided to take matters into his own hands and to send a message to the regime of Kim Jong Un: Messing with American hackers would have consequences. “It felt like the right thing to do here,” Caceres told WIRED at the time. “If they don’t see we have teeth, it’s just going to keep coming.”

North Korea Hacked Him. So He Took Down Its Internet

By Andy Greenberg

As he sought an outlet to broadcast that message to the Kim regime, Caceres told his story to WIRED while he carried out his attack, providing screen-capture videos and other evidence that he was, in fact, single-handedly disrupting the internet of an entire country in real time. But it was only just before going public that he decided to invent the P4x pseudonym for himself. The handle, pronounced “pax,” was a cheeky allusion to his intention of forcing a kind of peace with North Korea through the threat of his own punitive measures. He hoped that by hiding behind that name, he might evade not just North Korean retaliation but also criminal hacking charges from his own government.

Instead of prosecuting him, however, Caceres was surprised to find, in the wake of his North Korean cyberattacks, the US