Difference between revisions of "Security notes / Identification, authentication, authorization"

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===Passwordless login===
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===On authenticator devices===
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===On passwordless login===
 
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Given the issues with bad passwords, one proposal is to not use user-entered secrets at all.
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Given that passwords have issues, one proposal is to not use user-generated secrets at all.
  
This avoid the extra steps of password+device style 2FA.
 
  
  
Most proposals of passwordless actually amount to a shift from what you know to what you have.
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Most proposals of passwordless actually amount to a shift away from what you know, and more towards what you have.
  
 
This of course presents a shift in risks,
 
This of course presents a shift in risks,
ones that you need to teach your users,
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ones that you ''need'' to teach your users to not be riskier,
but for a lot of localized uses (like businesses) it can be pretty convenient.
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but for a lot of localized uses (like businesses) can be pretty convenient.
  
  
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::: and doing it with a password is just typical 2FA
 
::: and doing it with a password is just typical 2FA
  
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In some ways, we have taken password+device 2FA and removed the password.
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Or left it symbolically in, but don't really count it towards our 
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Keep in mind that biometrics were never a great idea ''as a single factor'',
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because very few are distinguishing enough.
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: either it has to be extremely strict (giving many false negatives)
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: or it will probably accept lots of people (giving many false positives)
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Fingerprints are one of the better options, but still come with many footnotes.
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In general, assume that biometrics are useful as added difficulty, only.
  
  
Biometrics are not a good idea as a single factor either,
 
because any single one is basically not distinguishing enough.
 
: Either it has to be extremely strict (giving many false negatives)
 
: or it will probably accept lots of people
 
  
 
A smart card or hardware token are a bad idea to use as a single one factor,
 
A smart card or hardware token are a bad idea to use as a single one factor,
because theft of the device basically means theft of the identitiy.
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because '''theft of the device basically means theft of the identity'''
: (consider that most types amount to "something you have knowing the password")
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in ways that the system can never hope to detect.
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(...not that it's much worse than "something you have that knows your password")
  
  
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===On n-factor authentication===
 
===On n-factor authentication===

Revision as of 13:31, 25 October 2021

Security related stuff.

Practical


Theory / unsorted

  • auth notes
how to do a login system badly
how to do encryption badly
Disk and file encryption notes

Separate parts

Identity

Authentication

Authorization

Auth systems - setup considerations

Local authentication

Centralized authentication

Shared authentication

Tokens and tickets

Delegated authentication / delegated access

This article/section is a stub — probably a pile of half-sorted notes, is not well-checked so may have incorrect bits. (Feel free to ignore, fix, or tell me)

Federated identity, Single Sign On

This article/section is a stub — probably a pile of half-sorted notes, is not well-checked so may have incorrect bits. (Feel free to ignore, fix, or tell me)



On authenticator devices

On passwordless login

On n-factor authentication

This article/section is a stub — probably a pile of half-sorted notes, is not well-checked so may have incorrect bits. (Feel free to ignore, fix, or tell me)


On TPM auth

Auth systems - practical considerations

Notes on implementations (and parts of them)

LDAP

LDAP is often used for authentication (via its binding mechanism, or sometimes via a proxy user that has wide access).

See also:

Kerberos

This article/section is a stub — probably a pile of half-sorted notes, is not well-checked so may have incorrect bits. (Feel free to ignore, fix, or tell me)

See also:

RADIUS

This article/section is a stub — probably a pile of half-sorted notes, is not well-checked so may have incorrect bits. (Feel free to ignore, fix, or tell me)

A framework that can be used for authentication, authorization and accounting.

See also:


*nix systems

This article/section is a stub — probably a pile of half-sorted notes, is not well-checked so may have incorrect bits. (Feel free to ignore, fix, or tell me)
  • PAM (Pluggable Authentication Modules), commonly used in OSes such as Linux, Mac OSX, a number of BSD variants (the others usually use BSD Auth), Solaris, AIX, HP-UX and more.
    • There is also a distinction between Linux PAM (used in linux) and OpenPAM, used in FreeBSD, NetBSD and Mac OS X Snow Leopard, and some linux distributions.
  • BSD Auth (used by some BSD variants)
  • NSS (Name Service Switch)


See also:

Microsoft windows components

This article/section is a stub — probably a pile of half-sorted notes, is not well-checked so may have incorrect bits. (Feel free to ignore, fix, or tell me)
  • NTLM ('NT Lan Manager'), mostly for SMB (see samba)
  • MS-CHAP, mostly for remote access
  • GINA (Graphical Identification and Authentication), which is the graphical login window.
GINA is basically a replacable executable; a common alternative is Novell's replacement GINA, and also of interest is pGina, a project that lets you authenticate against many different things.


See also:

SIP authentication

This article/section is a stub — probably a pile of half-sorted notes, is not well-checked so may have incorrect bits. (Feel free to ignore, fix, or tell me)

http://www.voip-info.org/wiki/view/SIP+Authentication

Athens, OpenAthens

This article/section is a stub — probably a pile of half-sorted notes, is not well-checked so may have incorrect bits. (Feel free to ignore, fix, or tell me)

https://en.wikipedia.org/wiki/OpenAthens

RSA SecurID

This article/section is a stub — probably a pile of half-sorted notes, is not well-checked so may have incorrect bits. (Feel free to ignore, fix, or tell me)

A two-factor system using a physical token that periodically generates a new code, based on a seed.

Relies on synchronizing the token with the login server's clock.


http://en.wikipedia.org/wiki/SecurID

Online delegated auth

This article/section is a stub — probably a pile of half-sorted notes, is not well-checked so may have incorrect bits. (Feel free to ignore, fix, or tell me)
  • Shibboleth
  • OpenID, usable for any system that wishes to support them (see also OpenID notes)
  • OAuth, for (service) APIs, bears similarities to OpenID (verify) [1] [2]
  • Windows Live ID (Hotmail, Messenger, Xbox LIVE, others), previously known under various names including the word passport
  • Google
    • Note that Google exposes their accounts via OAuth / OpenID (verify)





OAuth notes

This article/section is a stub — probably a pile of half-sorted notes, is not well-checked so may have incorrect bits. (Feel free to ignore, fix, or tell me)

See also:

OpenID notes

This article/section is a stub — probably a pile of half-sorted notes, is not well-checked so may have incorrect bits. (Feel free to ignore, fix, or tell me)

Short version

See this video, it's pretty clear on the basics.



What it is

OpenID lets you have an identity and relevant authentication for it stored/executed remotely to the sites that use it.

Which lets you use one identity, backed by a single OpenID provider, in many sites that want to use OpenIDs (which act as OpenID clients to the provider for each OpenID identity).

It lets you use a single identity for sign-on to many unrelated websites. It mostly solves cross-site identity verification - to the degree that clients can trust the OpenID provider, because the system is comparable to an orgnisation vouching for people you personally don't know.


Technically, OpenID servers are identity brokers and verifiers.

OpenID is decentralized in general, though each identity is centralized in that it implies a particular OpenID provider (exactly that?(verify)). The OpenID itself is URL-based, which is how an openID implies a provider, which is how an OpenID client knows what server to contact for verification.

As far as the side wishing for verification is concerned, the exchange is roughly:

  • site using OpenID: "Hey, this guy particularopenid is trying to log in. Do you agree that's them?"
  • OpenID server: "Hmm, particularopenid? Let's see, I'll check. Yup, I say that's them." (or, of course, the negative answer)

Note that the check and login happen on the openID provider - the OpenID client never sees the login information, or means of login.


The check proves that the identity described by the URL that is is indeed verified. (There is a bunch of security detail about going from site to site that side of things can for the most part be fairly simply trusted.)


Just how much that server's verification actually means to the client side, however, depends on the trust you place in the openID provider.

What it isn't

It does not really deal with trust - the only thing you really get is the information on whether a specific exchange succeeded.


Implicit (and pre-configured) trust in a system is always a bad idea (human trust is often one of the weakest links in a security system). To get back to the vouching-for-someone analogy: you would likely accept a good friend vouching for someone else, but probably not someone who's opinion you've come to disagree with, or a stranger. If some company vouches, you would still make some quick risk assessments and consider how their policies have worked out in the past.


A login in a decentralized login (OpenID or otherwise) is limited by:

  • The verifier's trustability.
Consider an openID server spam.com that answers 'yes' to each and every request that comes in.
  • Certain implementation details
OpenID allows setup of aliases, such as using a short domain name as an OpenID (by making it point to one). This means that this identity can change, e.g. when I lose the domain and someone else registers it.
OpenID allows clients to check whether it is verifying the same actual ID as before, but they have to actually do so to be secure against this.

Still, OpenID does make a number of things harder to fake. For example, if you got a comment or account request from spock.oid.example.com, and I can (informally) check that the person I'm thinking of indeed owns that openID, and that oid.example.com is trustworthy, that means they signed it.

Basic usage details

Signing up for an identity means a provider hands you a single URL that represents your identity.


This identity itself implies the site at which it the identity can be verified, which means login at a site you've never been before at involves:

  • typing your identity, such as example.myopenid.com
  • You get forwarded to the site that can verify this identity -- in this case myopenid.com
  • you log into your openid provider,
  • it tells you the new site wants access,
  • you allow it,
  • you get sent back to the new site

To the casual observer, it's a username/password deal, just at a central site.


OpenID has two main uses that I've noticed. The first is being the login step for an account elsewhere. This may well imply choosing a screen name there that is unrelated. This use is purely private, for my own ease of login.

The other is leaving a comment that is provably mine, say, on a blog (such as on livejournal -- except I have an account there anyway)


Identity delegate on a page

There are several openID providers, but you may not like some company's name in your ID. While you could technically run your own openID service, that's not very practical.

Something that is a lot easier is using a specific website -- usually a domain you own, to keep it short, or perhaps the URL to your main blog -- that you have control over.


Consider that losing control over that domain or website means that a different identity may eventually sit at the same openID url. If you stop owning that site, it is not guaranteed another identity won't be put there.

In fact, this is a feature too: since you delegate to a real openID service, you can change the delegate to another OpenID when for some reason you want to swith accounts, say, your openID service disappears.


OpenID providers

Some services imply an openID. For example, Livejournal users have an openID, period. AOL is implementing openIDs, and microsoft said it would too. Using one of these may be simpler. You can of course have several openIDs.

As to provider services, there are many. See http://openid.net/wiki/index.php/Public_OpenID_providers


Sites you can use OpenID on

Also a big list, and growing quickly. See https://www.myopenid.com/directory


Unsorted

http://www.openid-ldap.org/ (OpenID provider based on LDAP authentication)