This is the sequel post to the first part in which I mainly covered some elements of the specification wrt the “on-link” flag and the IPv6 subnet model.
In short each IPv6 address has an associated flag which determines if the host considers the respective address to be part of “a network where neighbors exist”. If this is the case ND is performed to talk to them, otherwise all communication with other hosts on that prefix is sent to the router. This flag is NOT set for DHCPv6 addresses (and, btw, just to make this clear already, there’s no way of setting it as part of the DHCP configuration procedure either) so communication with hosts with the same DHCPv6 provided prefix is supposed to go through a router, which in turn is very different (behavior) from the IPv4 world.
Enno Rey
A “Please, Don’t Waste my Time” Approach and the Sourcefire/Snort Evasion
This is a guest post from Antonios Atlasis.
Yesterday we (Rafael Schaefer, Enno and me) had the pleasure to deliver together our talk at BlackHat Europe 2014 named Evasion of High-End IDPS Devices at the IPv6 Era (by the way, latest slides can be found here and the white paper here). In this talk we summarised all the IDPS evasion techniques that we have found so far. At previous blogposts I had the chance to describe how to evade Suricata and TippingPoint. In this post I am going to describe some other techniques that can be used to evade Snort, and its companion commercial version, Sourcefire. The tool used to evade these IDPS is – what else – Chiron.
Continue reading Continue readingDeaggregation by large organizations
Some hours ago Iljitsch van Beijnum posted an email with the above subject to the RIPE Best Current Operational Practices (BCOP) mailing list.
Therein he describes the growing issue of (IPv6 prefix) deaggregation desires/approaches by certain organizations vs. the filtering practices of other organizations (providers). I touched this problem, from an enterprise’s perspective, some time ago in the second part of my blog post series on IPv6 address planning. Given we think that the discussion is heavily needed from several angles, I had actually submitted a talk on the topic twice (for the RIPE meeting in Warsaw in May and the upcoming one in London) which was unfortunately rejected at both occasions.
I’m hence very happy to see that a dialogue about the inherent dilemma might be started by Iljitsch’s mail. As a contribution to the development of a BCOP document I will hereby publish our draft slides of the talk which was initially planned. Furthermore two fellow IPv6 practitioners (Hi Roland & Nico!) and I plan to release a detailed paper with research results as for IPv6 prefix distribution at major European IXs in the near future.
Chiron – An All-In-One IPv6 Penetration Testing Framework
This is a guest post from Antonios Atlasis.
Last week I had the pleasure to give you my impressions regarding my experience about hacking for b33r at Ghent, that is, my participation at BruCON 2014 hacking conference. As I said among else, the reason that I was there was to present Chiron, my IPv6 penetration testing/security assessment framework, which was supported by the Brucon 5×5 program. The first version of Chiron had been presented at Troopers 14, during the IPv6 Security Summit.
Continue reading Continue reading“Hacking for a B33r” at Ghent
This is a guest post by Antonios Atlasis.
This week I had the pleasure to attend BruCON 2014. While participating at the Brucon 5×5 program, I had also the chance to attend this well-known European Con which is held in the beautiful city of Ghent.
The main event took place two days (on 25th and 26th of September), while some very interesting trainings were given in the previous days. There was mainly one track, plus some workshops that you could also attend, if you wished. You could book your seat at one of the workshops using an on-line scheduling system.
Continue reading Continue readingSecurity Implications of Disruptive Technologies
Yesterday I gave a talk with the above title in a private setting. Given it might be of interest for some of you, the slides can be found here.
Have a great weekend everybody
Enno
Continue readingMLD and Neighbor Discovery. Are They Related?
This is a guest post from Antonios Atlasis.
Today we had the opportunity at ERNW to have a full-day discussion about MLD. The discussion was led by Jayson Salazar who writes his thesis on the topic.
For the newcomers to IPv6 world, the purpose of MLD, a subprotocol of IPv6, as defined in RFC 2710, is “to enable each IPv6 router to discover the presence of multicast listeners (that is, nodes wishing to receive multicast packets) on its directly attached links, and to discover specifically which multicast addresses are of interest to those neighboring nodes.” MLD was updated by MLDv2 in RFC 3810 in order to “add the ability for a node to report interest in listening to packets with a particular multicast address only from specific source addresses or from all sources except for specific source addresses.”
Continue reading Continue readingAtomic Fragments vs. Fragmentation in the IPv6 “Real World”
This is a guest post by Antonios Atlasis.
Continuing the discussion about the IPv6 Atomic Fragments started at the IPv6 hacker’s mailing list and the freshly proposed draft RFC regarding the deprecation of the generation of IPv6 Atomic Fragments, we decided to check very quickly what is the current situation regarding the acceptance or the rejection of Atomic fragments in the “real world”. Thanks to Rafael Schaefer and the RISC lab at ERNW, we got some first measurements really fast.
Continue reading Continue readingPacket Too Big Messages and Atomic Fragments
This is a guest post from Antonios Atlasis.
Taking the chance from a discussion on the IPv6 hacker’s mailing list and the freshly proposed draft RFC regarding the deprecation of the generation of IPv6 Atomic Fragments, I decided to test very quickly what is the current status related with the latest and some of the most poplar Operating Systems (OS) status (whether they send Atomic Fragments in response to Packet Too Big messages, or not). The motivation behind this was to check which one of them is potentially vulnerable to the DoS attack using the technique described in the above proposed RFC and taking it for granted that Atomic Fragments are blocked in the real world (but more about this, in another blogpost in the near future).
Continue reading Continue readingEvading IDPS by Combining IPv6 Extension Headers and Fragmentation “Features” – The Story of My Life…
This is a guest post from Antonios Atlasis.
In the “A Novel Way of Abusing IPv6 Extension Headers to Evade IPv6 Security Devices” blogpost I described a way to evade a high-end commercial IDPS device, the Tipping Point IDPS (TOS Tipping Point, Package 3.6.1.4036 and vaccine 3.2.0.8530 digital), by abusing a minor detail at the IPv6 specification. As I promised at the end of that blogpost, this is not the end. In this blogpost I am going to describe several new and different ways of evading another popular IDPS, an open-source one this time, Suricata.
Continue reading Continue reading