My favourite SAML horror story, is that it used to be, that by default the main c implementation of xmlsig would not just check the sig with the public key specified but would also:
- check it against an hmac using a password specified in the attacker controlled document.
- check the signature using web pki (so the attacker could sign the saml document with their TLS key for their own personal domain and it would always be considered valid)
I honestly dont know how sites with saml arent getting hacked all the time. The only thing worse than the absolute terrible standards are the absolute terrible implementations.
I saw multiple implementations that looked for a signature, verified it, then just trusted the document as a whole rather than only the part that was signed. So as long as you had any signed SAML doc, you could provide an attention of your choosing and just bundle the signed one somewhere arbitrary inside of it.
It’s also enormous, I assume from the attempt to have nominally composable parts that could be reused for other flows.
It’s three entire specs bundled as one. One for the XML components, another for the documents you build from them, and another for the authentication flows built on top.
It is truly surprising how large the specs for each of these ecosystems are: PKI, Kerberos, TLS, OAuth, SAML, etc. They are gargantuan, especially when you include essential dependencies like DER codecs and ASN.1 compilers (PKI, Kerberos) or XML (SAML).
“There are two ways of constructing a software design: One way is to make it so simple that there are obviously no deficiencies, and the other way is to make it so complicated that there are no obvious deficiencies. The first method is far more difficult.”
The problem with this is the assumption that there's a simpler way to do all of this, and if only we could stop looking for large and complex solutions we could just land on the simple ones.
I listed a number of solutions, all built by different people, at different times, in different orgs, and some of those solutions (OAuth, SASL) being much more organic in how they evolved, and yet all are ultimately large and complex.
I think that hints at the problem space being... large and complex and requiring large and complex solutions.
What we _can_ do is avoid adding complexity unnecessarily, but what looks like a simplification today (e.g., picking the best current encoding system) might look like a terrible mistake in twenty years.
The thing is that they don't have to be that big at all, you could probably specify enough of PKI and TLS and SSH to cover most uses cases in, I dunno, 30-40 pages. However the standards bodies that produced them, termed "working groups", are more like standing committees that will (a) standardize any random idea that any member brings along and (b) are worse than the energizer bunny, they just keep going and going and going and going. Even ones that have been forcibly shut down like PKIX just keep going in other forms (LAMPS). You can't stop these standards mills, they'll just keep grinding out more stuff that no-one ever asked for, for all of eternity.
It sure sounds like it should be like this, but when you actually try you end up with not this. TLS is huge! Yes, but SSL 2.0 was smaller, and buggy as hell, so it had to evolve, and after 30+ years it became the monster that it is today.
Of course, SSL 2.0 did reference x.509, so hey, SSL 2.0 should have invented its own PKI. Except that Netscape might have come up with something terrible that worked in 1993 in labs but didn't scale to the web, or just full of security problems, or...
What you say sounds nice and right right up until you actually look at the details of what actually happened in real life, and how things actually evolve when they have little standards involvement.
Well, no-one held a gun to their head but there was a general "enough, already", aided by the fact that several of the main characters were retiring which helped wind it up. And then they just kept going as before under a new name and with an influx of new people who were unaware of how the original mess was made and why.
So if a WG is wound up and then continues under another name with mostly the same people doing the same things the original WG did it's not really wound up, is it? It's just changing the sign over the door with business continuing as usual.
First, anyone can participate. The only cost is the value of your time.
Second, yes, there are the usual suspects -- the ones who've decided to spend a lot of their time on whatever the area of tech we're talking about.
Third, working groups have charters that delineate what RFCs they will publish. Sometimes the work runs out. Sometimes the people run out of energy. Sometimes the tech is 'done', at least for a while. Then the WGs shut down.
Fourth, sometimes new work gets brought to the IETF in an area where the relevant WG has concluded, so then a new WG _may_ get spun up to take on that work.
The root problem with SAML is there’s a million and one permutations to do the same thing.
Signed assertions. Signed messages. Encrypted messages. Encrypted assertions. Sign after normalization. Sign before normalization. Encrypt then sign. Sign then encrypt.
That's because its built in part on XMLDSig, a genius idea to sign active content that can redefine its own semantics as it's being signed/verified. It's a triumph of ideology over common sense.
The first book that came out on XMLDSig, "Secure XML: The New Syntax for Signatures and Encryption", written by the chair of the working group, spent over half of its 500 pages wrestling with canonicalization, and even then it read more as a 250-page problem statement than a solution.
And that was before you got into deliberately malicious content that actively subverts the signature process.
I say this a lot, but: there was a conspiracy theory that NSA had infiltrated the IETF during the original IPSEC standardization effort and injected the "TLS BEAST" CBC IV chaining vulnerability, which is funny because we actually know exactly how that happened (professional academic cryptographers took out a petition to get the bug fixed and were shouted down by standards body gadflies who literally rejected the premise that there was such a thing as a professional academic cryptographer). This is really easy to see once you've done an engagement on DSIG security! Standards bodies are more than capable of fucking things up entirely on their own. If anything, NSA would risk making protocols stronger by intervening in their natural processes.
"Never attribute to malice what is adequately explained by stupidity". Or, in this case, design-by-committee by a bunch of people who haven't written ten lines of code in as many years. There have been several other cases where absolute no-brainer fixes, like one or two lines of code changed, to long-standing security problems, were filibustered, or blocked by WG chairs, for no explainable reason, and they can't all have been paid by the NSA to do that.
Yes, absolutely. And it's self-selection for mediocrity, people who are useless at any other task and prepared to argue endlessly over pointless technicalities that no-one apart from other professional meeting-goers care about are perfect for dumping onto standards committees.
bawolff · · focus · HN ↗
- check it against an hmac using a password specified in the attacker controlled document.
- check the signature using web pki (so the attacker could sign the saml document with their TLS key for their own personal domain and it would always be considered valid)
I honestly dont know how sites with saml arent getting hacked all the time. The only thing worse than the absolute terrible standards are the absolute terrible implementations.
stouset · · focus · HN ↗
tptacek · · focus · HN ↗
stouset · · focus · HN ↗
It’s three entire specs bundled as one. One for the XML components, another for the documents you build from them, and another for the authentication flows built on top.
cryptonector · · focus · HN ↗
arethuza · · focus · HN ↗
C. A. R. Hoare
cryptonector · · focus · HN ↗
I listed a number of solutions, all built by different people, at different times, in different orgs, and some of those solutions (OAuth, SASL) being much more organic in how they evolved, and yet all are ultimately large and complex.
I think that hints at the problem space being... large and complex and requiring large and complex solutions.
What we _can_ do is avoid adding complexity unnecessarily, but what looks like a simplification today (e.g., picking the best current encoding system) might look like a terrible mistake in twenty years.
pseudohadamard · · focus · HN ↗
cryptonector · · focus · HN ↗
Of course, SSL 2.0 did reference x.509, so hey, SSL 2.0 should have invented its own PKI. Except that Netscape might have come up with something terrible that worked in 1993 in labs but didn't scale to the web, or just full of security problems, or...
What you say sounds nice and right right up until you actually look at the details of what actually happened in real life, and how things actually evolve when they have little standards involvement.
cryptonector · · focus · HN ↗
Was the IETF PKIX WG "forcibly" shut down, or it merely concluded, with new WGs popping up to do similar things when needs arose?
pseudohadamard · · focus · HN ↗
cryptonector · · focus · HN ↗
pseudohadamard · · focus · HN ↗
cryptonector · · focus · HN ↗
First, anyone can participate. The only cost is the value of your time.
Second, yes, there are the usual suspects -- the ones who've decided to spend a lot of their time on whatever the area of tech we're talking about.
Third, working groups have charters that delineate what RFCs they will publish. Sometimes the work runs out. Sometimes the people run out of energy. Sometimes the tech is 'done', at least for a while. Then the WGs shut down.
Fourth, sometimes new work gets brought to the IETF in an area where the relevant WG has concluded, so then a new WG _may_ get spun up to take on that work.
koolba · · focus · HN ↗
Signed assertions. Signed messages. Encrypted messages. Encrypted assertions. Sign after normalization. Sign before normalization. Encrypt then sign. Sign then encrypt.
There’s too many ways to do too many things.
pseudohadamard · · focus · HN ↗
[deleted] · · focus · HN ↗
[deleted]
arethuza · · focus · HN ↗
NB I can absolutely see why canonicalization is required... just that it was the bit where I lost interest
pseudohadamard · · focus · HN ↗
And that was before you got into deliberately malicious content that actively subverts the signature process.
pseudohadamard · · focus · HN ↗
tptacek · · focus · HN ↗
pseudohadamard · · focus · HN ↗
bigfatkitten · · focus · HN ↗
They don’t build products, they don’t operate networks, and they don’t talk to customers.
pseudohadamard · · focus · HN ↗
bigfatkitten · · focus · HN ↗
HAIPE IS is classified, and mostly accommodates NSA’s private algorithms and key management practices.
IPMEIR is public, but it mandated the Suite B cipher suites and so I don’t know where it stands now with the move to PQC.
bigfatkitten · · focus · HN ↗