Last week I had the pleasure to participate at the first RIPE IoT Roundtable Meeting in Leeds (thanks! to Marco Hogewoning for organising it). It was a day with many fruitful discussions. I particularly enjoyed Robert Kisteleki‘s talk on RIPE NCC’s own design & (security) process considerations in the context of RIPE Atlas (at TR17 NGI there was an intro to Atlas, too).
In this post I’d like to quickly lay out the main points of my own contribution on “Balanced Security for IPv6 CPE Revisited” (the slides can be found here).
Enno Rey
Local Packet Filtering with IPv6
Just recently we discussed IPv6 filter rules for NIC-level firewalls (in a virtualized data center) with a customer. I’d like to take this as an opportunity to lay out potential approaches for local packet filtering of IPv6, which in turn might somewhat depend on the address configuration strategy chosen for the respective systems (for the latter you may refer to this post or to this talk from the Troopers NGI event).
Some of this has already been discussed in RFC 4890 Recommendations for Filtering ICMPv6 Messages in Firewalls but that document is from 2007 and things may have changed in the interim.
Let’s start with a quick look at the traffic which might be of interest. We will take a server perspective here, read: which types of IPv6 traffic might have to be accepted by a host/NIC firewall in order to support proper operations? I will discuss the following, with a focus on the implications of filtering them locally:
RIPE74 / Why IPv6 Security Is So Hard
I’m on my way back from the RIPE74 meeting in Budapest. It was a great event: quite a few nice technical talks in the plenary, productive working group meetings and some really good hallway discussions.
Big thanks to the RIPE NCC team for the smooth organization and for taking care of us!
Here’s some stuff I found particularly interesting:
- Andrew Alston’s take on “Anti-Shutdown Policies” (slides and video incl. extensive mic discussion)
- Philip & Maximilian from Freifunk Rheinland on their efforts (slides, video)
- Friso Feenstra on “That’s Why Rabobank Implemented IPv6” (slides, video) plus some insight into their address planning (slides, video)
- BCOP work on “IPv6 Prefix Assignments/Prefix Delegation” and “IPv6 Assignments for Hosting Providers“
- Jerry Lundström‘s DNS Replay Tool (slides, video, code)
- Jan Žorž (supported by Sander Steffann) on NAT64 testing (slides, video, code)
These were my own contributions:
Continue readingSome Quick Tips for Submitting a Talk to Black Hat or TROOPERS
Given the CfP for Black Hat US in Vegas ends in a few days – and as apparently some people have already started to think about their TR18 submissions – I’ll quickly provide some loose recommendations on how to write a submission here. There’s quite some reasonable advice out there already (the BH CfP site lists this and this which you should both read as well) but some of you might find it useful to get (yet) another perspective.
Continue readingTesting RFC 6980 Implementations with Chiron
In the recent post on the IPv6 properties of the latest MS Windows versions I announced another one providing details on the RFC 6980 related testing I had performed. So here we go.
When doing IPv6 security testing there’s mainly four toolkits which can be used:
- Antonios Atlasis‘ Chiron
- Marc Heuse’s THC-IPV6
- Fernando Gont‘s IPv6 Toolkit
- Scapy (whose IPv6 capabilities are, afaik, mainly maintained by Guillaume Valadon. some tutorial on IPv6 packet crafting with scapy can be found here).
Each of them has specific strenghts & limits, which will not be discussed here. For the testing I performed I chose Chiron as it has the most powerful options when it comes to IPv6 extension headers and fragmentation.
Continue readingIPv6 Properties of Windows Server 2016 / Windows 10
In this post we’ll take a detailed look at the properties of the Windows Server 2016 IPv6 stack.
I perform(ed) this exercise for several reasons:
- Server 2016 is the latest OS released by Microsoft so this might give an indication as for their plans & strategy when it comes to supporting certain specifications.
(here you may keep in mind that the ~50 IETF meetings having passed since the publication of RFC 2460 provided ample opportunity for creative minds to come up with ever new ideas for “enhancing” IPv6, without too much real-life feedback/reality checks from enterprise space though, as simply not many of such organizations have deployed it at scale… or are incentivized to send their employees to week-long meetings in expensive hotels on other continents twice a year…). - as I laid out in this post the configuration approach an organization takes for their servers might depend on the support of specific features.
- obviously for both IPv6 planning and operations it might be helpful to understand the respective behavior of individual operating systems (which is why we researched stuff like this or this in the past).
- many years ago Microsoft published white papers with details as for the TCP/IP parameters of their OSs (incl. stuff like registry parameters to control it etc.) but I’m not aware of such a document for Server 2016 or Windows 10. I hence hope this post can somewhat contribute to public knowledge of the intricacies of their latest IPv6 stack.
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Continue readingIPv6 Configuration Approaches for Servers
In this post I’ll discuss configuration approaches for systems which usually have been configured with “static” IP parameters in the IPv4 age/context (like servers in data centers). When it comes to IPv6 there are more options and we’ll have a look at their implications and potential advantages/disadvantages.
From my perspective there’s mainly four possible approaches which we see being implemented or considered in our (predominantly enterprise) customer space. Before we have a closer look at those let’s quickly write down requirements that the involved planners or sysadmins might have in mind when it comes to provisioning the systems in question. Some of those requirements might seem obvious but it could still make sense to note them for the discussion to follow. These might include:
Continue readingConsiderations on DMZ Design in 2016, Part 3: Some Notes on Firewall Rule Management
This is the 3rd part of this loose series on considerations of (operating) DMZs in 2016 (part 1 on the role of a DMZ is can be found here, part 2 on reverse proxies here).
Again, I dare to deviate a bit from the plan & order I initially had in mind – today I will cover one process whose maturity may significantly influence the overall security posture of a DMZ environment: firewall rule management.
(Securely) Updating Smart Devices / Some Considerations
How to provide updates to IoT devices – yes, I’m aware this might be a overly broad generalization for many different devices – has been the topic of many discussions in the last years (for those interested the papers from the “Internet of Things Software Update Workshop (IoTSU)” might be a good starting point).
Given Matthias and I will moderate the respective session at tomorrow’s IoT Insight Summit I started writing down some points that we consider relevant in this context.
IPv6 Source Address Selection
As we all know an IPv6 enabled host can have multiple addresses. In order to select a source address for a to-be established outbound connection, operating systems implement a source address selection mechanism that evaluates multiple source address candidates and selects the (potentially) best candidate. Criteria for this selection are defined in RFC6724 (which obsoletes RFC 3484).
To find out if there are differences as for the way various OSs implement this mechanism we performed a little study whose results can be found in this whitepaper. Those differences might be particularly relevant for data center environments or enterprise networks with a variety of heterogeneous client operating systems. If interested in IPv6 in enterprise networks this training that I’ll give in some weeks might be worth attending for some of you, too.
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