It's 2009. A seventeen-year-old in the UK is lurking in a forum he probably shouldn't be in. Someone posts a new tool — a keylogger, supposedly undetectable, shared as a gesture of goodwill in a community that runs on reputation. He downloads it. He runs it. Within forty-eight hours, every credential on his machine belongs to someone else.
He never finds out who did it. But he spends the next three months taking apart the binary, understanding exactly how it worked, how it phoned home, and why his antivirus didn't catch it. He learns more in those three months than in any course he'll ever take.
This is how the underground has always taught itself.
The version of cybersecurity education that most people know — certifications, Capture the Flag (CTF) platforms, corporate training programs — is a relatively recent invention. Before all of that, the curriculum was adversarial. You learned because someone attacked you, or because you were close enough to watch someone else get attacked, or because you decided to go hunting and discovered, quickly, that the prey was better at this than you were.
The best practitioners in the industry today didn't just read about threat actors. A lot of them spent time — sometimes uncomfortably close — studying them from the inside.
The Old School: You Learned by Getting Burned
HackForums. Void.cat. The carder boards that cycled through domain names every few months to stay ahead of takedowns. In the early 2000s and into the 2010s, these were the places where the security community — legitimate and otherwise — actually developed. Not in parallel. Together.
The culture of these forums had a brutal internal logic. Reputation was the only currency that mattered. You couldn't fake experience indefinitely — eventually someone would test you, bait you, or simply watch long enough to know you were performing. The penalty for pretending to be more than you were wasn't embarrassment. It was exploitation. The community had no interest in protecting people who hadn't earned the right to be there.
That meant the people who actually learned something were the ones who observed before they acted. They watched how trust was established and broken. They catalogued how tools were distributed — and how those same tools were sometimes backdoored by the people distributing them. The dynamic was almost Darwinian: the paranoid survived. The credulous handed over their machines.
This wasn't incidental. It was the curriculum.
A tool shared in a forum with a reputation-building pitch is also a social engineering attack. The vector is trust, not code. Understanding that — really understanding it, from the receiving end — produced a generation of people who could spot the same pattern years later when it showed up as a spearphishing campaign against a financial institution. The technical details change. The psychology doesn't.
Hunting the Hunters: When Defenders Went Offensive
In 1986, a systems administrator at Lawrence Berkeley National Laboratory named Cliff Stoll noticed a 75-cent discrepancy in his network accounting records. Most people would have rounded it off. Stoll followed it.
What he found, after months of painstaking work with no formal intelligence training and no dedicated security budget, was a hacker working on behalf of the Komitet Gosudarstvennoy Bezopasnosti (KGB) — moving through US military and research networks, looking for Strategic Defense Initiative (SDI)-related material. Stoll documented the whole thing in The Cuckoo's Egg, published in 1989. It remains one of the most precise accounts ever written of what hands-on threat intelligence actually looks like.
Cliff Stoll's account of tracking a KGB-linked hacker through US research networks is considered the founding document of hands-on threat intelligence. Stoll had no training, no budget, and no mandate — just a 75-cent accounting error and the refusal to let it go. The book predates the term "threat hunting" by two decades and describes the practice better than most modern frameworks do.
Stoll didn't have a methodology. He developed one by chasing a real adversary in real time. He learned to think like the attacker because he spent months watching him work — logging every session, mapping every pivot, understanding the pattern of reconnaissance. By the time the case was closed, he understood that attacker better than the attacker's own handlers probably did.
That model — learn by observing a live adversary with patience and precision — became the foundation of what we now call threat intelligence. But it took practitioners decades to formalize what Stoll had done instinctively.
Brian Krebs took the same approach from a different angle. A journalist by training, Krebs built one of the most credible threat intel operations in the world — documented daily at KrebsOnSecurity — not through technical certifications but through deep, sustained immersion in underground markets. He bought stolen credit card data to understand how the market functioned. He built personas in carder forums. He mapped the infrastructure of fraud operations by participating, observing, and reporting — while criminals simultaneously launched Distributed Denial of Service (DDoS) attacks against his website, sent heroin to his home address, and dispatched a Special Weapons and Tactics (SWAT) team to his front door.
The attacks against Krebs are instructive in themselves. The underground doesn't harass people who don't understand it. The volume and sophistication of the retaliation he received was a direct measure of how accurately he was seeing the ecosystem. He was getting burned because he was getting close.
Marcus Hutchins and the Education Problem
In May 2017, a twenty-two-year-old malware researcher going by the handle MalwareTech found a kill switch in WannaCry — the ransomware worm that had just crippled the UK's National Health Service (NHS), Telefónica, Deutsche Bahn, and dozens of other organizations — by registering an unregistered domain he found hardcoded in the malware. The registration cost him about ten dollars. It stopped the spread of one of the most destructive cyberattacks in history.
The speed at which Marcus Hutchins identified and acted on that kill switch — within hours of WannaCry going public — was not the product of a structured education. It was the product of years spent in close proximity to exactly this kind of code. Hutchins had spent his adolescence in underground forums, studying malware, reverse engineering samples, understanding how threat actors built, deployed, and maintained their tools. He knew what he was looking at because he had been looking at things like it for a long time.
Three months after WannaCry, the US Department of Justice (DOJ) arrested Hutchins on charges related to malware he had allegedly written years earlier, before his work as a defender. He eventually pleaded guilty to two counts and was sentenced to time served plus supervised release. He has been transparent about the complexity of his history — that his understanding of the threat landscape came, in part, from having been inside it.
The Hutchins case is the sharpest illustration of a tension that the industry mostly prefers not to examine directly: the skills that make someone exceptional at defense are often the same skills developed through adversarial exposure. Not everyone's path crosses a legal line. But the pattern — deep, personal familiarity with how attackers actually operate — is consistent across the practitioners who are genuinely good at this work.
The Underground as a Living Curriculum
In February 2022, following Conti's public support of Russia after the invasion of Ukraine, an anonymous source leaked the ransomware group's internal chat logs. Over 60,000 messages. Years of operational history. The full architecture of a mature criminal enterprise laid bare: how they recruited affiliates, how they negotiated ransoms, how they handled internal conflicts, how they managed their own Operational Security (OPSEC) failures.
For threat intelligence analysts, it was the equivalent of a competitor leaving their entire internal documentation on the street. The researchers who worked through those leaks systematically — mapping organizational structures, identifying Tactics, Techniques, and Procedures (TTPs), correlating infrastructure — came out the other side with a level of understanding that no training course could have produced. You cannot simulate the internal communications of a sophisticated Ransomware-as-a-Service (RaaS) operation. You can only read them when they surface.
The same dynamic plays out at a smaller scale constantly. Researchers who maintain honeypots don't do it to collect data points. They do it to watch attackers work in real time — to see the actual sequence of commands run after initial access, to observe which vulnerabilities get exploited first, to understand what the attacker prioritizes when they think no one is watching. The honeypot is a classroom. The attacker is the instructor, and they don't know they're teaching.
When a Command and Control (C2) domain expires or is abandoned, researchers can register it themselves and redirect the botnet traffic to a controlled server. This turns an attacker's dead infrastructure into a passive intelligence feed — revealing how many systems are still infected, what malware families are calling home, and sometimes details about the original campaign's scope and targeting. All without touching a single victim machine.
Some researchers go further — registering expired Command and Control (C2) domains to sinkhole active botnet traffic, mapping malware infrastructure by letting samples run in controlled environments and observing their callback patterns, sitting in Telegram channels where threat actors announce operations in real time. None of this is passive. It requires the same kind of fluency in underground culture that can only come from having spent time there.
The Conti leaks, the honeypots, the sinkholed domains — they're all versions of the same thing Stoll was doing in 1986 with a modem, a printer, and a 75-cent discrepancy. The technology scales. The method doesn't change.
You Can't Teach Adversarial Thinking. You Have to Catch It.
Back to our seventeen-year-old in 2009. The one who downloaded the wrong tool and spent three months taking it apart. He's a composite — I've encountered versions of that story enough times that it stopped feeling like a coincidence and started feeling like a pattern. The specifics vary. The structure is always the same: an early exposure to how attackers actually operate, absorbed at a level of detail that no lab environment replicates, that shapes everything that comes after.
The certification path — Offensive Security Certified Professional (OSCP), Certified Ethical Hacker (CEH), whatever comes next — teaches technique. It does not teach how adversaries think, what they want, how they adapt when something doesn't work, how they build and maintain trust in environments where everyone is trying to exploit everyone else. That knowledge comes from proximity. It always has.
The best threat intelligence analysts I've encountered share something that isn't on any resume: they're fluent. They read a forum post from an underground marketplace and immediately understand the social dynamics, the status games, the signals that indicate whether an actor is credible. They look at a phishing lure and recognize the cultural references the attacker used to make it land with a specific target. They understand the attacker's perspective not as an abstraction but as something they've observed directly, from close range, for a long time.
That fluency isn't taught. It's caught — through years of patient, careful attention to how the other side actually operates. Sometimes that attention got people burned. Sometimes it put them in complicated positions. In every case, it made them better at the work than they ever would have been otherwise.
Ethical hacking, at its best, has always been built on this. Not on frameworks. Not on controlled environments. On the hard-won understanding that if you want to know how an adversary thinks, there's no shortcut better than watching one work.
// Thoughts on the underground as a classroom? Disagree with something? Continue the thread on X.
> Reply on X @JeanCDevenish →// All references to underground forums and threat actor activity are documented from publicly available sources, academic research, and published journalism. Nothing in this article constitutes operational guidance. If you're doing threat intelligence work, get authorization in writing, every time.