What is Dumpster Diving?

Dumpster diving is the concept of sifting through trash. Typically this doesn’t necessarily involve physically entering a dumpster but rather just reaching in, but it can involve literally “diving” into dumpsters. The concept is fairly general and often involves people that are struggling to make ends meet claiming discarded but still edible food or items that can be resold.

For example, in first-world countries, supermarkets often throw food away once it has reached its best-before date, or even if it just has imperfections. This food is generally still perfectly edible, and some people choose to take it from the bins. Furthermore, often people throw away functional goods that they no longer want or need. A dumpster diver may identify these items and resell them.

But where does the tech come in? Well, sometimes people and companies throw away tech items or data. A dumpster diver may be able to make remarkable use of this.

Dumpster diving phreaks

While dumpster diving has probably been going on since humanity has had trash to rummage through, it generally wasn’t considered too much of an issue until things got “phreaky”. One of the early forms of hacking didn’t directly involve computers. Instead, phone systems were the targets. From the 1950s to the 1970s telephone systems in the US were automatically switched through the use of tones. To dial a number you pressed keys, these keys each had a distinct audio tone, and the system decoded these tones and put you through.

Because these tones were played through the same communication system as normal speech, it was possible to replicate the tones and get put through. Furthermore, the tones also controlled the rate at which the call was charged so fees could be reduced or dodged entirely by playing custom tones. Making use of this knowledge was called “phreaking” the person doing so was called a “phreak”. The term “phreak” is a sensational spelling of “freak”, using the first two letters from “phone”. Many such figures are highly respected in the computer hacking culture.

To be able to make proper use of the system a fair amount of knowledge was needed. Some of this could be scrounged together by just listening to the tones. But many phreaks learned what they needed to by dumpster diving. Specifically, they would go through the dumpsters of phone companies and read through the system manuals that had been simply thrown away. In this way, the phreaks often became even more knowledgeable about the precise intricacies of the phone system than the people running it.

Dumpster diving hackers

With phreaks learning about telephone systems by dumpster diving, many early hackers also used the same techniques. Again, by targeting the dumpsters of companies making or using computer systems, especially big mainframe systems, they could eventually get their hands on user manuals and other technical documents. With this information and with a driving sense of curiosity, these hackers often ended up knowing the system better than its architects. In this way, they could be incredibly effective at gaining access by exploiting vulnerabilities.

Often the vulnerabilities exploited weren’t anything massively complicated. Instead, they could be as simple as not having an authentication mechanism at all and then connecting it to the Internet, or a network with Internet access. In many cases, these early hackers didn’t particularly use their knowledge maliciously. Yes, they hacked in, illegally, but often they’d just poke around, leave some sort of “I was here” flag message and leave again without breaking anything.

Dumpster diving leakers

Generally, if you don’t need something anymore you just throw it away. It can be fairly easy to not consider what data is on paper or hard drives that are being thrown. In some cases, dumpster divers have come across sensitive data on discarded paper records. Data can also be accessed from discarded hard drives, in or out of computers.

This exact risk is why many organisations and governments require that sensitive paper documents are shredded before they are trashed. It’s also why there are policies on hard drive wiping and even destruction.

The legal side of things and other risks

Technically, in most cases, dumpster diving is illegal. The contents of the bin belong to the owner of the bin and taking them is stealing. Generally though, this is extremely rarely enforced. Ethically, it makes sense to allow this. If someone throws something away, clearly they have no further use for it. If someone else then sees this and decides they can make use of it, it generally doesn’t harm the previous owner. The problem comes when what’s thrown away can be misused. Realistically though, this could and probably should be covered by other laws rather than theft.

Dumpster diving is also very much not recommended. You have no idea what’s in a dumpster. There could be toxic chemicals, biohazardous waste, or sharp metal or glass. Dumpsters may also be emptied without anyone actively checking inside them first which can be life-threatening for a person inside.

Conclusion

Dumpster diving is the act of rummaging through trash. It doesn’t necessarily mean explicitly diving into a dumpster. Generally, it’s done looking for food or items that can be resold. Historically though, hackers and phreaks used it as a method to gain access to product manuals and documentation. This gave them a significant amount of knowledge of the system and made it easier to manipulate. Spies, private eyes, and police may also dumpster dive as part of an investigation. Generally, if you’re disposing of sensitive information either physical or digital, it should be destroyed in some manner before being disposed of. This mitigates the potential threat of dumpster diving.