 διδεχνή was δεν θα δημιουργηθεί σε αυτή τη πολιτισία σε μια κέρδι, δεν θέλαμε να μοδιθεί από κάθε κέρδι να μοδιθεί τη πολιτισία So what would be the main advantage? The main advantage is that you actually know what security level is your operating system using in general and because I had to convince my boss I wrote some reasons why we actually και έχουμε πάνω αυτό και εμπλήθεια ότι είναι πραγματικά επίπεδο για να δημιουργήσουμε το σύστημα γιατί χρήμαστε το συστημα του πρόσφυρου. Έτσι, ένας αντιμετωπίσιο είναι ότι θα χρησιμοποιήσουμε την δημιουργία του πρόσφυρου να δημιουργήσουμε το συστημα του πρόσφυρου. Γιατί είναι ότι αν έχεις δημιουργήσει ένα HCDPS ή κάτι που χρησιμοποιείς την κρύπτα, τι είναι οι καλύτερες εξοπιστές που έχεις να κάνεις. Βεβαίνει να δείξεις σε εξοπιστές like bettercrypto.org, δυοχθεί το PDF από 90 παίδες ή ακόμα more, ρωθεί εκεί, πώς να δημιουργήσεις τις εξοπιστές σε ένα σύστημα που η σύστημα του πρόσφυρου είναι εξεπτοποίητο για στιγμή στιγμή, και να δημιουργήστε το σύστημα για τον对ύσιο των ενδυακών, λοιπόν, γιατί θα πιστεύεις αυτό στην πόρφα ότι θα caminhoσαι να儒ομαι ένας και πρέπει να δiate σας τον εξοπιστής, επειδή θανεφού του Mixed upload Revureaty Avenue να με συνασυφέρει το συστήταμα του πρόσφυρου. Είμα για acquired Portal Continue, η δημιουργία τηςuneguia by using a consistent level across the operating system Βεβαίνει ένα κλασό της εμπανιστικής δημιουργίας που αντιμετωπίζει σε συγχρονομές στον λειβό. Για παράδειγμα, αν έχεις παραδείγει τελευταία, είχαμε ένα ατακόντυο στον τελευταίο, το λόγω του, που αντιμετωπίζει σε κάποιες λειβόνες, δημιουργήσει πάνω από τα άλλα. Αν έχουμε ένα συγχρονομή, αυτό το ατακό δεν θα μπορεί να είναι εκεί. Το άλλο είναι να είναι εύκολο να παραδείγμαστε. Δεν ξέρεις πως το πρόγραμμα που αντιμετωπίζει σε κάποιες λειβόνες, ξέρεις τι ατακόντυο your programs θα χρησιμοποιήσεις. Θα θα είναι οι ατακόντυες που αντιμετωπίζουν. Δεν χρειαστεί να παραδείγμαστε. Λίγο για την ιστορία που είμαστε στην Φαδόρα. Είμαστε στην Φαδόρα 21, που ήταν τελευταία, και χρησιμοποιήσαμε σύστημα βαδικοίδωσης. Είμαστε κοινωνικές σύστηματος για εξαιρετικότητα. Τώρα, στις τέτοιμοι, είμαστε πρόγραμματος να έχουμε μία εξαιρετικότητα, αλλά να δημιουργήσουμε τη δημιουργία, να έχουμε ένα από τέτοιμοι εξαιρετικότητα, ένα που είναι η λιγασία. Αυτό was a bit insecure, included all algorithms, it even enabled MD5, and the idea of the legacy was to be able to connect, to set up your system in a way that you can connect, even on a network where you have really 10-year-old computers, and you cannot connect to them otherwise. And the default level was a bit conservative, it didn't have algorithms that were considered to be broken, and pretty much it was about on an 80-bit security level. It also provided a future security level, but it was around 11 bits security offered, but that also meant that you couldn't connect to around 80% of the internet if you enabled this. So of course the system came by default on the default level, and we piloted on a few applications on Fedora 21, while on Fedora 22 we converted several libraries and applications to use this policy by default, like Apache HPD, Lite HPD, Lib, Micro HPD, and also the command line applications we shipped. In Fedora 23 we added also the BIND software to the system value critical policies, because in DNSSEC you also use algorithms, and we would like to be able to restrict certain algorithms from being used in DNSSEC when they are considered broken. So what was our approach? Every all up to now was a bit theoretical, but what we actually did, if you have already set up a server using either open and sell or no TLS, you have probably noticed that at some point you have to specify a server-shoot string, for example in open and sell it can be like that to enable the high level Cypher suites except MD5 and such. In the TLS it will be something enable the normal Cypher suites with only TLS 1.2 in this example, for example. And we figured that since we have several applications, and every having this kind of strings on the configuration files, why not agree on a single string that we set on every application, and upon when this string is accounted by open and sell or no TLS, it will just load the default system-wide policy. So that's pretty much the idea. And the next step we just modified most of the applications we see to change the included by upstream, let's say example configuration file, to use our system-wide policy string. Some problematic cases were the applications which hardcoded their defaults into the code, and in these cases we just also modified the code to use our shift policy, our default policy. That was a very brief description. If you want to see more about this, it's on that URL. And ideally we wanted to cover everything, let's say, that every cryptographic aspect of the application in that policy, from signature to MAC algorithms to Cypher algorithms to key exchange algorithms, elliptic curves allowed, the size of parameters allowed for RSVR, if you help the protocols allowed, and even compression. Our current state is that no TLS is able to cover the whole set of options, while on open and sell we are restricted to MAC algorithms, Cypher and key exchange. Although we plan to extend open and sell as well, the reason, if you don't know already, is the fact that open and sell doesn't allow much freedom in what's to specify in the Cypher-shoot string. You can only specify the Cypher-shoot, it's not any other parameters. We also have paths for NSS, if you don't know, the NSS is a library used by Firefox, the TLS library used by Firefox, to cover also all these parameters. It's currently under upstream consideration, and we haven't included it yet in Fedora. So our current state is that we have already sent patches in new TLS, they're upstream, that was pretty easy for me because I was the appreciative of new TLS, and we have pull requests in open SSL and NSS, and all of these are under upstream consideration for open and sell. For example, we know that upstream is very happy with these patches, but not merged yet, so we hope it will be soon. An interesting aspect of this is that after we sent these patches to NSS, the long-term attack came out, and we realized that if that patch was in place with the Fedora default settings, NSS wouldn't have been a vulnerable to long-term. I think that's an interesting aspect, because I'm presenting here something to increase proactively the security of the system, but we actually see that if we had managed to fully deploy it, we would have actually increased the security of the system and prevent a new attack from being a real threat. So, a few lessons learned during this deployment. We have an initial deployment with Fedora 21, and we selected very conservative settings, our default level of Fedora 21 included SSL3 and RC4, it was before the pull attack, and it went pretty smoothly because of that. When in Fedora 22 we decided to drop SSL3.0, it didn't take more than 10 minutes to receive a bug report that we broke something. So, as a lesson I would say that it's better to be conservative in the beginning when you deploy for a pilot rather than be strict and say SSL3.0 is already 12, it's broken, let's drop it, because we realized there are applications that could only use SSL3.0, not because of Fedora, but because the Windows server, let's say, was only using SSL3.0. Another thing is that, unlike CVs, where they have to be fixed in a very short amount of time because let's say you have all the newspapers talking about you, that you are broken and this kind of stuff, when you send the proactive security patch to some project upstream, you have very slow response times, you get probably mails that tell you, ok, we like it, we are going to evaluate it, but when it actually comes to the point to merge it, it takes much time. The third thing is that, I believe actually, that's my opinion, that it pays off having such a system-wide security level. The same attacks we have seen in the last years on TLS and SSL, like PUDL or the CBC Cypher sheets, the RC4 attacks, it would have been much easier to simply change the policy and remove these options from the protocol or reorder them, rather than modify each and every application to eliminate these options. Also, as I've mentioned, the long-term attack wouldn't have been an issue. What are our future plans? At the moment, our first priority is to make sure that everything is upstream, everything we have contributed so far to NSS and OpenSSL is upstream, and we would like to include the Java, SSL and TLS implementation to the policy, and that's partly maybe easier than we initially thought, and probably in the future to include OpenSSL, but as I say, it's Kerberos or even GnopiG there in the policy, so that you actually set up your security level centrally all over the operations, irrespective of TLS or all the actual protocol for everything that relates to crypto. I have set up a tracker there on this URL, if you are interested for more information, where are we? The reason I'm actually here is because we want to make this policy, not only but pretty much universal, and I hope I have attracted your attention, and this is the project we use at Zithab for the policies. Do you have any questions? What about certificates? Are they centrally managed too? Yes, the idea, the parameters that I presented before, was to include also certificates, let's say the size of parameters used in the certificates, in RSA certificates. Well, the certificates used to authenticate some remote site, for example in Debian there's EDC, SSL certs. Ah, you mean the CA certificates. Yeah, actually in Fedora we have a common CA certificates for open SS and green TLS. So we pretty much have already shared this, and this part was about only the algorithms. Because if I remember correctly, Firefox, Icewizzle and Debian used them in the past but Noma uses them because I think something upstreamish changed. So I think that's pretty. I'm not aware of this but it will be by news indeed. The problem I found when I was using security strings, is that you can only use plus or minus, you can't use intersections. So when you have a large thing like system default, but you won't say only perfect for security strings, you can't actually say use system defaults which are perfect for security, but you have to either take system default minus everything that's not perfect for security or alternative list, all the perfect security which also are a member of the system default by basically manually looking through the list. That is correct. You cannot do so advanced substitutions there. This is for me a big problem with any concept like system defaults but I can't reduce them if I want to guarantee perfect for security. You could also set your system defaults to be only perfect for secrecy. Currently in Fedora we don't have, but that is not a limitation, let's say. Hi there. Is there also something in progress to get more programs to be comfortable with? As I read the policy you suggest for everything that is configurable to have this system policy as default and to change everything that has hardcoded to change it to the hardcoded value to the system. In my eyes this has the problem that it's still hardcoded. So if one application that is hardcoded needs something more permissive you have to keep the system-wide setting more permissive for this. So it would be nice to have an orchestrated afford to ping all upstreams to have everything configurable. That's a correct observation and pretty much our approach of changing the hardcoded we hoped it would end up in something like this if somebody would want something worse or better security policy he would have to request it from upstream. But I didn't think it should be part of this project to force every upstream to make it configurable because on some applications you may not want it configurable. Okay, time is over. Thank you for being here.