Let’s be honest. Most businesses don’t really know what open source intelligence (OSINT) exists about them out there in the wild. Even fewer realise that what’s out there on the surface web and dark web can be used to launch real and very damaging attacks.

The phrase “open source intelligence” often sounds more technical than it needs to. It simply means information that anyone can access, no hacking required. This could be an exposed email address in a forum post, a staff member’s leaked credentials on a breach site, or your forgotten staging server indexed by a search engine. That’s surface web. Add in dark web marketplaces and forums and now you’re into the deeper waters, with chatter about your company, stolen internal documents, or mentions of vulnerabilities related to your tech stack.

Here’s the kicker: most organisations don’t even glance at this stuff. It’s not that they don’t care, but rather that they’ve not built the processes or brought in the tools or people to do it well. Some make a start, often focusing on the more obvious bits, a single password dump or a phishing domain. They’ll look at one piece at a time, rate it as high or low severity, and move on. If they’re security savvy, they might apply a bit of context, maybe correlate it to a known campaign or threat actor.

But this approach misses the big picture.

Attackers don’t operate in isolated pieces. They think in chains, in sequences. A leaked internal IP here. An exposed AWS key over there. A developer’s GitHub account with overly helpful readme notes. None of those are devastating alone. But put them together? Now you’ve got a clear attack vector. And it may be invisible to a business looking at those pieces individually and rating them as low risk.

This is where the real value of OSINT comes in, not just spotting it, but correlating it.

Imagine a scenario. A marketing intern reuses a weak password that gets leaked. Low risk? Maybe. But what if that same email address is found in a document referencing a staging site that is still live, which happens to use basic authentication. Then you find a repo on GitHub with old internal documentation about that same environment. Separately, none of these are setting off any alarms. But together, they form a route in. A foothold. And for a motivated attacker, that is more than enough.

Another example: a single credential in a breach might be shrugged off. But when that email appears in a dark web forum post offering access to an “enterprise system”, and you notice that same person has recently posted on LinkedIn about a promotion to infrastructure team lead — suddenly you’ve got a reason to pay attention. The context turns a routine alert into something urgent.

OSINT is not just data. It is signal. The problem is that businesses treat it like noise unless it screams.

To be truly proactive, businesses need to look at the connections between seemingly minor pieces. They need to think like an attacker would, creatively, laterally, and with the patience to explore how puzzle pieces might fit together.

In short, OSINT needs to move from being a checklist activity to something more like threat modelling. It should drive decisions, shape detection rules, and inform red team scenarios.

And no, it does not require huge teams or budgets. It requires curiosity, context, and the right mindset. Tools can help, sure, but this is a thinking game first.