| > where secrecy and marketing hype is used to attempt to conceal the flaws. That's literally the practical basis of security through obscurity. > Others, like my comment above, are talking about systems carefully engineered to have no predictable or identifiable attack surfaces- things like OpenBSDs memory allocation randomization, That's exactly the opposite of 'security through obscurity' - you're literally talking about a completely open security mitigation. > I’ve found when it is impossible for an external bad actor to even tell what OS and services my server is running- or in some cases to even positively confirm that it really exists- they can’t really even begin to form a plan to compromise it. If one of your mitigations is 'make the server inaccessible via public internet', for example - that is not security through obscurity - it's a mitigation which can be publicly disclosed and remain effective for the attack vectors it protects against. I don't think you quite understand what 'security through obscurity[0]' means. 'Security through obscurity' in this case would be you running a closed third-party firewall on this sever (or some other closed software, like macos for example) which has 100 different backdoors in it - the exact oppposite of actual security. [0] https://en.wikipedia.org/wiki/Security_through_obscurity |
If you're not understanding how memory allocation randomization is security through obscurity- you are not understanding what the concept entails at the core. It does share a common method with, e.g. using a closed 3rd party firewall: in both cases direct flaws exist that could be overcome with methods other than brute force, yet identifying and specifying them enough to actually exploit is non-trivial.
The flaw in your firewall example is not using obscurity itself, but: (1) not also using traditional methods of hardening on top of it - obscurity should be an extra layer not an only layer, and (2) it's probably not really very obscure, e.g. if an external person could infer what software you are using by interacting remotely, and then obtain their own commercial copy to investigate for flaws.