June 2015 - ipv6-wg - mailman.ripe.net

Extension Headers / Impact on Security Devices
by Enno Rey 26 Jun '15

26 Jun '15

Hi, hope everybody had a great #RIPE70 meeting. We did! Many thanks to the organizers and chairs! With regard to the strong position on ext hdrs that I expressed in the session yesterday pls allow to add some material/sources: - this is a paper laying out how we could circumvent some major (both commercial and FOSS) IDPS solutions in their at the time of testing latest versions, by various combinations of extension headers and fragmentation: https://www.ernw.de/download/eu-14-Atlasis-Rey-Schaefer-briefings-Evasion-o…. - here's some thoughts and preliminary results of tests performed to circumvent stateless ACLs: http://www.insinuator.net/2015/01/evasion-of-cisco-acls-by-abusing-ipv6-dis…. http://www.insinuator.net/2015/01/the-persistent-problem-of-state-in-ipv6-s…. We have a (somewhat) ongoing research project looking more closely on the interaction of ACLs and extension headers. For the moment I can only state that it's not just Cisco who are "affected". More results will be available in some months. If the chairs consider this appropriate we will happily give a presentation on this stuff in Bucharest or at another occasion. We could even bring some devices to Bucharest to do some practical testing and demos "in some side room" during #RIPE71, for those interested. We can even do the latter without any official part in a session, if there's interest. As for the topic itself I'd like to summarize our position as follows: - it has not happened in the past 17 yrs (since publication of RFC2460) that compelling, Internet-scale use cases of extension headers have been brought up. - we're hence quite sceptical as for the "we might see cool use cases in 15-20 yrs" position someone expressed at the mic. - from a security perspective they turn out to be a nightmare for (a number of) current security architectures and controls. it is hence understandable (and we actually advise to do so) that they are blocked at the _border_ of networks that have not yet managed to identify a compelling use case. - looking at the "liberty" RFC2460 provides as for ext_hdrs (wrt to their number, order, options, fragmentable vs. unfragmentable part etc.) we do not expect that type of security issues to disappear soon (the main reason why we did not continue the IDPS research was that the involved student eventually delivered this thesis. one can probably find much more issues provided time & resources). Adding more parsing cycles & intelligence (read: silicon) is not an option, at least not for sth that doesn't have a use case. - the results of this (blocking) approach have been observed and documented by Jen & Fernando and others (Tim Chown). - now that "this vicious circle" has gained sufficient ground it will be even less incentivized to develop a compelling use case. which is why we do not expect to see one in the future. === Everybody have a great weekend and for those still in AMS: have a safe trip home! Best Enno -- Enno Rey ERNW GmbH - Carl-Bosch-Str. 4 - 69115 Heidelberg - www.ernw.de Tel. +49 6221 480390 - Fax 6221 419008 - Cell +49 173 6745902 Handelsregister Mannheim: HRB 337135 Geschaeftsfuehrer: Enno Rey ======================================================= Blog: www.insinuator.net || Conference: www.troopers.de Twitter: @Enno_Insinuator =======================================================

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[training] RIPE NCC Webinars - new dates
by Training Services 18 Jun '15

18 Jun '15

Dear colleagues, We are pleased to announce the dates for the RIPE NCC Webinars for the coming quarter. These interactive on-line learning sessions take about one hour, and give you the opportunity to learn and interact with our trainers without leaving your desk. In the next 3 months you can participate in the following Webinars: - Advanced RIPE Atlas Usage (NEW!) - Introduction to the RIPE Database - RIPE Database - Advanced Topics - IPv6 in the RIPE Database - IPv6 Addressing Plan - Webinar for New LIRs - Resource Certification (RPKI) Register now at https://www.ripe.net/support/training/learn-online/webinars Participation is limited to 20 people, so don't hesitate if you want to take part! If you have any questions, please email <training(a)ripe.net>. We look forward to seeing you online. Kind regards, RIPE NCC Training Services

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[news] Finnish IPv6 Launch Event on 8 June in Helsinki, Finland
by Marco Hogewoning 16 Jun '15

16 Jun '15

Dear colleagues, Finnish IPv6 Launch Event on 8 June in Helsinki, Finland On Tuesday 8 June, Viestintävirasto, the Finnish telecoms regulator, hosted a seminar on the launch of IPv6 in Finland across a broad spectrum of sectors. Emile Aben and I participated in this meeting on behalf of the RIPE NCC. This half-day meeting was the pinnacle of a project that started about two years ago with a renewal of the work programme of the national IPv6 task force. This renewal led to efforts to coordinate the deployment of IPv6, with the seminar date set as a milestone by which to achieve nationwide support for IPv6. The project found support from all major access providers as well as hosting companies and content providers including the national broadcaster, YLE, and MTV. We are pleased to see this strategy has paid off: the regulator estimates that approximately five million Finnish Internet connections are IPv6 enabled to date. Real-time measurements by APNIC also showed a rapid increase of IPv6 users over the preceding week: the percentage of end users observed using IPv6 quickly rose from almost nothing to 4.7%. DNA achieved the most spectacular deployment: the percentage of their customers using IPv6 skyrocketed to 16% and is still increasing. During the seminar, various operators reported on their experiences during the deployment. They also looked forward to resolving any remaining issues and using the knowledge gained to further advance IPv6 adoption throughout the country. More information about the initiative can be found at http://ipv6nyt.fi. For detailed statistics on the IPv6 deployment, see: http://stats.labs.apnic.net/ipv6/FI?c=FI&x=1&p=0&r=1&w= Regards, Marco Hogewoning -- External Relations - RIPE NCC

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Re: [ipv6-wg] [v6ops] Extension Headers / Impact on Security Devices
by Mark ZZZ Smith 16 Jun '15

16 Jun '15

From: Ca By <cb.list6(a)gmail.com> To: Eric Vyncke (evyncke) <evyncke(a)cisco.com> Cc: "v6ops(a)ietf.org" <v6ops(a)ietf.org>; "ipv6-wg(a)ripe.net" <ipv6-wg(a)ripe.net> Sent: Tuesday, 16 June 2015, 8:32 Subject: Re: [v6ops] Extension Headers / Impact on Security Devices On Monday, June 15, 2015, Eric Vyncke (evyncke) <evyncke(a)cisco.com> wrote: Enno, As you probably know, Cisco handles PSIRT issues with care, so, I have no clue on this specific advisory. My own (educated) guess is that the packet causing a LC reload is fully RFC 2460 compliant but unusual, so, probably (a guess again) a combination of extension headers triggering a bug. In this specific case, I would not blame IPv6 or RFC 2460 but rather my own company (even if the affected versions were quite old as new IOS-XR versions appear to be immune to this bug). And I appreciate the humor in your rhetorical question about which FW could protect a CRS... Air gap probably :-) More generally, regarding the 'parsing of the header' and performance, my understanding (and I am NOT a HW engineer) is that there are multiple ways to parse the header chain: - purely software in low-end devices, should have a marginal performance impact - specific ASIC in middle-end devices (read high end enterprise), probably some limitations and heavy performance impact (but again within one organization, so, easier to fix the root cause) - a lot of specialized network processors in high-end devices (SP gears), which is a similar case as the 'low-end device', performance impact but marginal as parsing the chain of headers is not that hard after all _when_ coded correctly As the extension headers are specific to IPv6, this is an area when we will all learn (and have learned already) a lot of things... I respectfully disagree with your last sentence. Of course, destination AS/host SHOULD only accept useful, known and legit ext headers; but, why would an ISP filter on ext headers if they do not harm their own infra or a customer infra? Do you envision an Internet where only TCP/443 and UDP/43 would be accepted? Last point, the Internet will have to use IPv6 for 10 or 20 years at least. If the IETF/ISP block all new _options_ in _existing_ extension headers, then we will be stuck in 1997 for network innovation. While I do not like taking security risks, I even fear more the lack of innovation. I keep hearing this and it is very bizarre to hear With regards to 1997, believing that there will be innovation in the narrow waist of hour glass (network layer), that is very 1997. The network layer is stable and boring.... Hence it being narrow. Innovation is welcome everywhere except network in the e2e model / Absence of evidence is not evidence of absence. / Consider what the network and host situation was in 1997 (wired network access, desktops outselling laptops, dialup Internet for residential, corporates in total probably being the largest spenders on Internet access) to today and the near future (wireless networks, smartphones/tablets being the dominant Internet access device in some markets - and they're multi-homed, M2M/IoT considered to be place where the greatest expansion of Internet connected devices is going to occur in the near future.) / IPv6 has had relatively little adoption, and it is only starting to increase quite rapidly in the last few years and that is mainly because of mobile networks. There hasn't and still doesn't seem to be much thinking about how IPv6's differences from IPv4's can be taken advantage of yet - an "IPv4 first" or an "IPv4 == IPv6" mindset seems to be still very common (I think the network virtualisation space is where this is might be most prominent - I think most of the technologies they're inventing require fork lift network upgrades, so the costs of deploying IPv6 at the same time become a lot less significant. So if there is a "cheap" opportunity to deploy IPv6, and IPv6 is going to be the long term network layer 3, why not optimise for it now? That was the thinking behind my "Enhancing Virtual Network Encapsulation with IPv6" draft) / We don't want to disable innovation opportunities that IPv6 may provide before people have arrived at an "IPv6 first" or "IPv4 != IPv6" mindset. Let's talk on Thursday at Silvia's IPv6 Conference in Zurich ;-) -éric On 11/06/15 11:58, "Enno Rey" <erey(a)ernw.de> wrote: > >the problem here is the definition of "normal IP packet" as of RFC2460. >To illustrate this I just quote from today's Cisco advisory (Cisco IOS XR >Software Crafted IPv6 Packet Denial of Service Vulnerability) on packets >potentially crashing CRS-3 line cards: > >"The vulnerability is due to incorrect processing of an IPv6 packet >carrying IPv6 extension headers that are valid but unlikely to be seen >during normal operation. An attacker could exploit this vulnerability by >sending such an IPv6 packet to an affected device that is configured to >process IPv6 traffic. An exploit could allow the attacker to cause a >reload of the line card, resulting in a DoS condition." > >two question come to mind here: > >- is a "valid but unlikely" extension header chain "normal"? >- what ("combination of FW & IPS or whatever") would you put in front of >a CRS? > >my (sad) expectation is that we'll see much more of these (types of) >issues in the future. given the current level of freedom that the RFC2460 >leaves (see also discussion/picture in >http://www.insinuator.net/2015/06/is-ipv6-more-secure-than-ipv4-or-less/) >"properly parsing an IPv6 packet, let alone in wire speed" seems a pretty >much unsolvable task to me. > >That said I still fail to see any useful extension header besides AH&ESP >(not even FH) to be transported in the Internet. > >best > >Enno > > > > > > > > If your firewall cannot implement this policy, then >> it is time to change or to use a combination of FW & IPS or whatever. >> >> - network person: as I will live with IPv6 for the rest of my life, >>then I >> want a way to extend it and I need any packet to travel to my source to >>my >> destination. Any IPv6 packet should be able to traverse the >> Internet/private network as long as its layer-3 header is valid >> (filtering/dropping can be done exceptionally for good operational >> reason). Did we remember the IPv4 teardrop attack? It is blocked by >> default by most routers for years ;-) >> >> Bugs will plague us for ever... And make our life more complex than the >> above description of course ;-) >> >> -??ric >> >> On 17/05/15 20:43, "Silvia Hagen" <silvia.hagen(a)sunny.ch> wrote: >> >> >Hi >> > >> >I keep stumbling about that "recommendational wording" in RFC 2460 >> >everytime I teach it. >> > >> >Couldn't we update RFC2460 and make this list a strict order? >> > >> >I would want my firewall to notify me if the EHs in a packet do not >> >follow the list. >> >And limiting the number of possible EHs per packet might be a good >>idea. >> > >> >Silvia >> > >> >-----Urspr??ngliche Nachricht----- >> >Von: ipv6-wg [mailto:ipv6-wg-bounces@ripe.net] Im Auftrag von Benedikt >> >Stockebrand >> >Gesendet: Sonntag, 17. Mai 2015 18:39 >> >An: ipv6-wg(a)ripe.net >> >Betreff: Re: [ipv6-wg] Extension Headers / Impact on Security Devices >> > >> >Hi Enno and list, >> > >> >Enno Rey <erey(a)ernw.de> writes: >> > >> >> hope everybody had a great #RIPE70 meeting. We did! >> >> Many thanks to the organizers and chairs! >> > >> >and thanks to the actual speakers as well the speakers we had to turn >> >down due to time constraints, too:-) >> > >> >> If the chairs consider this appropriate we will happily give a >> >> presentation on this stuff in Bucharest or at another occasion. >> > >> >Sounds good to me! >> > >> >> - looking at the "liberty" RFC2460 provides as for ext_hdrs (wrt to >> >> their number, order[...] >> > >> >Actually, as far as I'm concerned that's the real core of the problem. >> >Or more specifically, the first two lines of RFC 2460, section 4.1: >> > >> > When more than one extension header is used in the same packet, it >>is >> > recommended that those headers appear in the following order: >> > >> >followed on the next page by >> > >> > Each extension header should occur at most once, except for the >> > Destination Options header which should occur at most twice (once >> > before a Routing header and once before the upper-layer header). >> > >> >Note in particular that these are not even RFC 2119 "SHOULD" or >> >"RECOMMENDED" and such. >> > >> >The impact here is actually at least twofold: >> > >> >- It is impossible to implement this as a simple pipeline architecture >> > in hardware; at least for cases deviating from the "recommendations" >> > above this effectively becomes either excessively complex to >>implement >> > in hardware or an invitation to DoS when implemented in software on >>an >> > otherwise hardware router. >> > >> >- As I understand it, at least some of the issues you have found are >> > effectively based on violating the second paragraph quoted, making it >> > impossible to come up with a lower bound on how long the header chain >> > can actually get and therefore leading to the fragmentation related >> > attacks and similar you have discovered. >> > >> >The original idea was that the extension headers are processed strictly >> >in the order they occur, so one question to ask is if there is any >>valid >> >reason to violate these "recommendations" for other than malicious >> >purposes. >> > >> > >> >Cheers, >> > >> > Benedikt >> > >> >-- >> >Benedikt Stockebrand, Stepladder IT >>Training+Consulting >> >Dipl.-Inform. http://www.stepladder-it.com/ >> > >> > Business Grade IPv6 --- Consulting, Training, Projects >> > >> >BIVBlog---Benedikt's IT Video Blog: >>http://www.stepladder-it.com/bivblog/ >> > >> > >> > >-- >Enno Rey > >ERNW GmbH - Carl-Bosch-Str. 4 - 69115 Heidelberg - www.ernw.de >Tel. +49 6221 480390 - Fax 6221 419008 - Cell +49 173 6745902 > >Handelsregister Mannheim: HRB 337135 >Geschaeftsfuehrer: Enno Rey > >======================================================= >Blog: www.insinuator.net || Conference: www.troopers.de >Twitter: @Enno_Insinuator >======================================================= > >_______________________________________________ >v6ops mailing list >v6ops(a)ietf.org >https://www.ietf.org/mailman/listinfo/v6ops _______________________________________________ v6ops mailing list v6ops(a)ietf.org https://www.ietf.org/mailman/listinfo/v6ops _______________________________________________ v6ops mailing list v6ops(a)ietf.org https://www.ietf.org/mailman/listinfo/v6ops

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Looking for info on IGP choices in production dual-stack networks
by Victor Kuarsingh 09 Jun '15

09 Jun '15

RIPE IPv6 Folks: Philip Matthews and I are co-authors on an active draft within the IETF related to IPv6 routing design choices. To ensure we are gathering sufficient data we are looking for an expanded set of input from operator forums as well (vs. just the v6ops IETF list). The draft is found here -(https://tools.ietf.org/html/draft-ietf-v6ops-design-choices). We are looking for information on the IGP combinations people are running in their dual-stack networks. We are gathering this information so we can document in our draft which IGP choices are known to work well (i.e., people actually run this combination in production networks without issues). The draft will not name names, but just discuss things in aggregate: for example, "there are 3 large and 2 small production networks that run OSPF for IPv4 and IS-IS for IPv6, thus that combination is judged to work well". If you have a production dual-stack network, then we would like to know which IGP you use to route IPv4 and which you use to route IPv6. We would also like to know roughly how many routers are running this combination. Feel free to share any successes or concerns with the combination as well. We are looking particularly at combinations of the following IGPs: IS-IS, OSPFv2, OSPFv3, EIGRP. If you run something else (RIP?) then we would also like to hear about this, though we will likely document these differently. [We suspect you run RIP/RIPng only at the edge for special situations, but feel free to correct us]. And if you have one of those modern networks that carries dual-stack customer traffic in a L3VPN or similar and thus don’t need a dual-stacked core, then please email us and brag ... If you are on multiple lists at RIPE, NANOG or the IETF, we apologize for any redundant emails you may get (we are just attempting to reach the widest audience possible). Philip Matthews Victor Kuarsingh

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New on RIPE Labs: IPv6 Deployment in Estonia
by Mirjam Kuehne 04 Jun '15

04 Jun '15

Dear colleagues, In case you missed Tarko Tikan's description of the IPv6 deployment in Estonia on other lists, we put the story on RIPE Labs: https://labs.ripe.net/Members/tarko_tikan/ipv6-deployment-in-estonia Kind regards, Mirjam Kuehne RIPE NCC

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