In the context of a) information security and b) an operating system such as Windows 10 or OS X, what actually constitutes a "hack"? Most non-technical end-users associate the term "hack" with the deliberate stealing of information or an event where somebody had unauthorised access to their data. However, the CSO website seems to have a much broader definition of a "hack" to include fake AV messages, pop-up messages and browser redirects.

So if you were documenting a problem with an end-user system which had "pop-ups", would you really feel comfortable in reporting that the system was "hacked"?



5 Answers 5


The term "hack" has many meanings depending on context and popular use and has both malicious and benign meanings.

In general, it means that someone intentionally circumvented system design or controls in order to get the system to do something the designers did not intend.

You can hack a system to provide new, helpful functionality, or you can hack a system in order to let it permit you access to something it was designed to keep you away from. There is a desire in many circles to call a "malicious hack" a "crack" so that there is a clear distinction.

In your scenario, you see the effects but you have no idea about the intent. Therefore, you cannot conclude from the effects alone that there was intent or what that intent was. If the user permitted the malicious activity, then it is no longer a "hack" or a "crack".

So, no, I would not be comfortable with concluding that a system has been "hacked" because I saw pop-ups. Yes, there is undesired system behaviour, but there could be a number of reasons for it.


I would state that a hack is an undesirable activity with unauthorized access to assets. This can be, but is not limited to, doing an unauthorized action on a private machine such as modifying or transferring data.

This means a "hack" is broader then unauthorized access for most people. When your computer is infected by a cryptolocker, most people would say that their computer was "hacked", even though no access was given to an adversary.

If you take a look at a classic defense model or security landscape, you will see that a user has assets to protect. These assets can be protected by taking security measurements to protect against threats used by adversaries.

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Not all adversaries are hackers, just like not all threats are hacking related. Power outage for example is a threat to your assets and you have to take security measurements, but a power outage does not constitute as hacking to most people. This is why it is important to look at threats as well as adversaries.

Depending on your adversary, a fake anti-virus message or browser redirect is a threat to your security (and therefore to your assets) but there is no unauthorized access yet and therefore is not a "hack" in my opinion, rather a malicious action (or threat).


To me, the term "hack" is a bit of a meme. It doesn't have a clear definition (other than to mean "something bad happened around an account being accessed in a way you didn't want"), it's scary to hear, and to the extent it has a technical meaning it's generally misused by people who aren't familiar with the field.

So to answer your initial question:

if you were documenting a problem with an end-user system which had "pop-ups", would you really feel comfortable in reporting that the system was "hacked"?

No, I would never use the term "hacked" in this context. Technically, "hack" tends to mean something closer to "information security controls were breached and information exposed by a malicious party," so on the surface this scenario doesn't make sense in that regard.

Moreover, "hack" is an informal, abstract term. In documenting a problem or software behavior, it is never good practice to use this kind of terminology for something so concrete.


I would define a 'hack' as Unauthorized access to a system obtained by bypassing/compromising its security.

All things derived from there (data destruction, transmission, installation/execution/removal of software, monitoring/spying or anything the unauthorized user may do) are secondary possible effects.


It's a collection of related ideas, much as the concept of ''breach'' is a collection of bad actions. It generally means unauthorized:

  • access i.e. violation of some protection or boundary
  • transmission of data
  • installation of software
  • modification of data or software
  • execution of software

Many ''hacks'' happen because someone installs ''free'' software that they downloaded and installed it on purpose, which is authorized by the deception is that the software does something nasty.

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