That is constricted thinking. If brute-force becomes cheap your scheme is broken
Errr... you need to upgrade your crypto knowledge. If brute-force means 1 mio. times the lifetime of the universe, and it becomes a million times cheaper, it is still a tiny bit impractical.
My crypto knowledge is fine. What do you think I meant by "cheap" above? And you're accusing me of arguing semantics. Do you measure the cost of brute-forcing RSA-512 in terms of the lifetime of the universe? Please upgrade your crypto knowledge if that's the case.
Citing a real-world example, what is the difference between RSA-512 vs. RSA-2048 that you would consider one secure and the other insecure?
Well, using a real-world metaphor, if RSA-512 is a grain of sand (let's say 10 micrograms) then RSA-2048 is the entire mass of the entire universe. Put into a grain of sand in yet another entire universe, where every grain of sand represents an entire universe and then taking that entire universe and multiplying it by a couple trillion. That's not a matter of "brute-force becoming cheap". If every grain of sand in the entire universe were a supercomputer that could break one RSA-512 per second, RSA-2048 would still be secure against brute-force attacks.
This is just dissembling now. So many words, because you refuse to acknowledge a simple point: algorithmically there is no difference between the two.
Obscuring the version info increases the cost (time, bandwidth) of the attack.
Yes, but it is not a security measure. It's a one-time tiny benefit. We recommend it because it doesn't really cost you much and thus it's a net-gain. Real-world example: If you have a server running at a version that has a known exploit in the wild, then you wouldn't consider obscuring the version number as a mitigating action, would you? It does not provide security.
Same issue again. So many words to exlain why you prescribe it, and so many words to then disown it as a security measure. The point is simple and clear. Obscuring that version info is a tiny little security measure. No individual thing provides security -- so your line at the end does not apply.
In ASLR you *obscure* addresses from an attacker. It's an important security mechanism, any modern OS is incomplete without it, and there's just no escaping the fact that it is nothing but a form of obscurity.
No, you don't. ASLR has nothing to do with "security through obscurity". Please stop playing tricks with semantics. You won't be able to quote even a single serious source that puts ASLR even in the vicinity of "security through obscurity".
Playing tricks with semantics? After you ramble on with some nonsense about grains of sand instead of just discussing the core of the issue? As an attacker, you know there's a freaking stack (for example), don't you? With ASLR the only difference is that you don't know where it is anymore -- because it has been *obscured* from you. That's not a semantic trick -- you are the one dancing around with endless verbiage to defend a stupid and pointless stigma over the word 'obscurity'.
You're missing my point again, which is that you *should* really be talking about *cost*.
Negative. Cost is one factor, but not the only one.
What are the other factors? Everything translates into cost eventually.
Plus you don't generally know the cost equations of your attacker.
You know the relatives costs inside your system. What is the cheapest point of attack in your system currently? That is your first priority. Once that's dealt with, ask and answer that question again and again. You will *raise* the *cost* of breaking your system by doing so. You don't need to project the attackers cost to do that. You are deliberately being dense now.
Sometimes, work time is expensive, sometimes it is cheap.
Sometimes people ramble on when they lose the plot. This was a great discussion until this post.
Sometimes acquiring an exploit is expensive, sometimes it is cheap.
Somebody originally developed it at some cost. Whatever the economoes of them selling it, if you raise that initial cost, you improve the chances of them looking at someone else's product for holes instead of yours.
Sometimes, you all you need is being a less easy target than the guy next door
My exact words were "As a security professional your job is to make their cost of doing business in your neighborhood prohibitively high." You're saying the exact same thing back to me and lecturing me on how wrong I am.
and sometimes, costs don't even matter to your attacker as long as they can afford it at all.
Actually, that's just a scenario where the attacker is willing to pay such a high cost that nothing you do cryptographically will deter them. If they are willing to hold a gun to your head or a loved one's head to make you give up your passwords, you better make sure they can't find you (i.e., make your location obscure).
You should be talking about security. Cost is one factor, since most security measures are imperfect. But sometimes, you have one that isn't. One-time pads can not be cryptographically cracked, for example. Cost of cryptoanalysis stops being a factor if you use one-time pads, and the efforts shift to stuff like key distribution.
We are talking about security. The currency in this trade is *cost*. One-time pads are a great example of that -- for an effectively unbreakable system, its pretty seldom used. Why do you think that is? Because it's manual nature means that the *cost* is not worth it to the good guys.
Established on slashdot, and in journalism circles perhaps.
Nice strawman, I'm not biting. You are trying to re-define the meaning of the term in order to win an argument.
Whatever man... This shit is getting pointless...
Real world example: would you ever let your clients share even the slightest information about a DB schema publicly? Even if you authenticate all entry points? C'mon man!
There's a difference between "don't tell them if it doesn't serve a purpose" and "the security of this system lies with this being kept a secret". If a client would ask me if they should publish their DB schema on their website, I'd not tell them the sky is falling, I'd ask them why. Because the security of their DB should not rest with the schema being a secret.
Who said anything about the security if their DB resting with the schema being a secret? Did I even imply that this will be your only security mechanism? And you're accusing me of strawmen? WTF man?
I used to work with the SELinux crowd, contributed a couple patches, held a couple talks. For demo purposes, I once put the IP address and root password of my notebook on a piece of paper. With a proper policy, you can do that on an SELinux system. I wouldn't recommend it, but once again, the security of the system rests with the policy and the role authentication, not the root account.
You're lecturing me about stupid shit that adds nothing of value again (see grains of sand above). Stop doing this! See your above strawman -- did I suggest that hiding your IP address is a single point of defense you should rely on? WTF is this logic?
Maybe it's all semantics with you. I don't consider just any tiny bit that might or might not make the attackers job a little bit more difficult to be a security feature.
You accuse me of semantics, and then argue semantics in the very next sentance.
Countercheck: Would you consider re-arraging the keys on your keyboard a security feature? It certainly makes things more difficult, but c'mon!
Another strawman -- citing a silly example doesn't make your point valid. It just means you used a silly example as a strawman. Do you consider re-arranged keys obscurity? If yes, then why?
Obscurity is an inextricable part of security. Anyone claiming otherwise has never worked in the profession.
I do and I have and still do. Obscurity is not a part of security. It's an additional low-cost measure you can take if it makes you feel better, but your system should be just as secure without it.
Low cost measure of what? Low cost measure of what? Ans: security.
That is why I don't consider it a part of security - it should not affect the security of your system in any measurable way. It's more obvious in crypto: Your attacker can know which algorithm you use. Whether or not he knows should not affect the security of your encrypted data. If it does, your algorithm is broken.
This is a pitfall people fall into too easily. The algorithm has to be public knowledge else even the good guys wouldn't be able to use it. But you do obscure something -- the key. And it still comes down to cost. If something else in your system is easy (cheap) to bypass, will you object to your attacker "but, but, I was using crypto!!"?