After 50 years of software engineering, why are computer systems still insecure? I don't get it.

Two questions: (i) What's so hard about just denying or restricting networked access to bad actors who lack passwords? It's not like these bad actors arrive with crowbars and dynamite; they only have bits and bytes, right? (ii) Once a bad actor has achieved networked access, why haven't operating-system kernels been re-engineered to make privilege escalation unfeasible?

I am not looking for a book-length answer but merely for a missing concept. If you can see the flaw in my thinking and can shed a little light on the flaw, that will be answer enough.

Is there some specific reason top scholars have not yet been able to solve the problem? Is there a sound reason we still have, say, bootstrapped compilers and unauditable microprocessor designs, despite the long-known security risks?

Is there some central observation, answerable at StackExchange length, that ties all this together? Why are computer systems still insecure?

Update: Commenters have added some interesting links, especially "Is Ken Thompson's compiler hack still a threat?"

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    This reads more like a long rant, less than a focussed question. Without knowing your intent, it's hard to edit the question into shape for you. I'm also not sure whether this site is the ideal venue for security-related questions. One concept you are missing is the fundamental security asymmetry: an attacker has to get lucky only once, a defender has to succeed every single time. It's not like the defenders know all the bugs in their systems and decide to ignore them. Complete prevention of all bugs is impossible.
    – amon
    Jan 7, 2017 at 14:35
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    @thb Physical isolation ("air-gap") is a legitimate security strategy but there are many situations where it cannot be achieved. On the other hand, information security exists on a continuum that reaches as far as human intelligence ("HUMINT") in the context of intelligence gathering (spying and reconnaissance), which is that there is no leak-proof ways of preventing information leaks as long as human actors are involved. Even "for your eyes only" systems can leak information.
    – rwong
    Jan 7, 2017 at 15:12
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    But questions about bug-proofing (or software defect reduction) have been asked and answered before on this site; if you have a focused question on software defect prevention that hasn't been asked/answered before, perhaps you can open a new question.
    – rwong
    Jan 7, 2017 at 15:13
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    And also the interchangeability between a brute-force and a wrench: xkcd.com/538
    – rwong
    Jan 7, 2017 at 15:36
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    See softwareengineering.stackexchange.com/q/339652/21172 (the question immediately after yours) for a hint.
    – kdgregory
    Jan 7, 2017 at 16:16

4 Answers 4


At its core, the problem is that software is complex. For any site, you have all of the JavaScript to make the site run. You have the server to handle requests. You have the cache to handle in flight data. You have the CDN to store all of the content. You have some database to store all of the data. You have backup servers where the data goes. You have logging servers where info can end up. You have all of the libraries written by others, but used by all of these parts. You have the web servers, written by others. You have the operating system, and all of the things installed there.

All an attacker needs to do is find one mistake in any of this code, and the gig is up. Programmers are human, so invariably, given a million opportunities to fuck up, we will.

But that is just the technical side. Even if all of the code is secure, users still have passwords, and they're usually bad. There's still the ability to call up tech support and ask for "your" password reset, gaining control of an account that isn't yours. You can still bribe someone who does have access (as of 2000, 80% of intrusions were made by people on the inside - vengeful programmers, bored secretaries, greedy salesguys). There's still social engineering people into believing that fake email is a legitimate request for a password reset.

The problem isn't solved because there isn't a single problem, they're not all technical problems, and most of them are damned hard in the general case.

  • +1. Useful answer. Appreciated. I had in mind something analogous to memory safety (as in Rust), which allows automated tools to quickly audit millions of lines of code. That's an architectural solution to the memory problem. Setting aside the human factor (tech support, password reset), I gather that we have no good architectural solution to the security problem. This intrigues me. I have never read why such an architectural solution, a solution which corrals your "million opportunities," should not exist. That's too big a question for SE, but underneath, it's what I had in mind. Thanks.
    – thb
    Jan 7, 2017 at 15:39
  • I should have said, "I had never read why...." Your answer does, of course, give an interesting, concise explanation.
    – thb
    Jan 7, 2017 at 15:46
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    @thb: maybe you simply missed to read the right articles? The buzzword you might be looking for is "security by design", I am sure if you google it, you will find some resources.
    – Doc Brown
    Jan 7, 2017 at 16:42
  • @DocBrown: yes, thanks. In my late 40s, I begin to find that buzzwords increasingly don't reach me. I had kept searching for "inherently secure kernel" and words like that. Security by design. That's probably the word I had wanted but hadn't known.
    – thb
    Jan 7, 2017 at 16:57
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    @thb - you seem to have a number of assumptions that are coloring your view of this. Most security problems aren't exploits. They aren't bugs. They're code doing exactly what the code is supposed to do, but the data just happens to be sensitive, or the person viewing it just happens to be not who the code trusts it to be.
    – Telastyn
    Jan 7, 2017 at 17:10

First people and companies buy insecure computers then try to manage the problem. They still sell no matter the lack of security.

Second people that understand the vulnerabilities have confidentially contracts that makes it difficult to share the ideias with hardware and os developers. Os and hardware developers do not have a good understanding of the business needs.

I for one am a big fish but I can't use my company email then in some communities people does not realize I have experience with big things and serious problems that merits attention and thinks I am nuts. There is many professionals like me.

Third, patents and authoring rights do avoid good ideas to be shared. See how fast China is developing and how far behind US is getting. the patent system was taught as a mean to protect the small inventor, but in the hand of big companies become a way to force their products forward by filing bogus claims against their competitors.

Forth many people that discover the system failures live from it and will not reveal the secrets unless paid for. And just in the last decade or so p2own start paying prizes.

Sixth the incremental security is profitable.

Seventh this is a complex problem that would require a huge effort and most of the problems was discovered after each generation of computers and software are put in place.


The reason is that it's hard to make computers both useful and secure. You can make them completely secure, by disconnecting them from the internet and taking other measures, but then they aren't so useful. So we start adding features and capabilities. We connect our PCs to the internet. The WWW is fun but static. So we create Javascript and allow people to do things like banking via a web browser. It's a pain to keep entering a password, so we create session IDs and store them on the client in cookies or hidden form fields. Then we let users simultaneously open multiple web sites. Uh-oh! Better make sure that other web sites can't read that other-site session id... and so it goes.


There's a simple other reason: people are lazy and not aware. It will not hit me. That's the same attitude you take when walking on the street. It's always the others that suffer. Take Mail for example. Point to point encryption is available since decades, but nobody really uses it. Not too long ago I signed my mails and got them back from Mickeysoft users claiming their Outlook refused to show them without being able to decode the signature. So I turned that off again. Meanwhile it seems I don't see complaints any more, but sending encrypted mails between trusted parties? No way.

Another observation: security is not absolute. It's always relative. And people (I said they are sort of lazy) tend to use the least arduous way. Which in turn means less security.

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