IPv6 Security

IPv6 is the natural progression for internet addressing.  With IPv4 addresses limited to just over 4 billion,  estimates have predicted a public address space shortage in months rather than years.  With over 7 billion people on the planet, it's easy to see why, especially as many in the western world, use smart phones and tablets as well as standard laptops, resulting in a individual using more than one address simultaneously.

What is IPv6

Internet Protocol version 6 is seen as a direct replacement for Internet Protocol version 4, operating at the internet layer of the OSI model.  There are a few main differences between the two approaches, mainly the fact that IPv6, has a considerably larger pool of available addresses - around 340 undecillion (lots of zero's..).  An IPv6 address is longer too, at 128 bits compared to the shorter 4 byte, 32 bit IPv4 address.  IPv6 also contains a fixed host identifier based on the devices MAC (Media Access Control) address.



One of the major implementation headaches of IPv6, is that there is no default interoperability with IPv4.  Tunnelling and translation options are available to allow devices using the different protocols to communicate.

Whilst the uptake of IPv6 is slow, it's becoming a major area of investigation for CIO's planning strategic reviews of network deployment and security.

Security Concerns

Many security attack vectors are triggered due to one thing - cash.  Malware in recent years has become a complex organised crime related activity, resulting in big pay days for those who are successful.  As more organisations look to deploy IPv6, attacks will increase and vulnerabilities will be exploited.

The main area of practical concern, would be that many network administrators will have relatively fewer skills in managing IPv6 networks, than the traditional IPv4 environments.  This is natural of course, due to the history, popularity and training available for the now legacy v4 infrastructures.  Security knowledge, implementation and scanning of those networks will therefore more likely contain security mis-configurations or tooling that is not properly utilised to effectively detect, protect and report on IPv6 issues.

One of the interesting concerns that has been raised about IPv6, is that of privacy versus security.  Whilst the IPv6 address is longer, it also by default, contains the network devices MAC address.  This MAC address is hard coded into the physical device, making it non-transferable and therefore easier to track.  MAC's are broken down to contain vendor specific codes, allowing identification of network interface cards, phones, printers, routers, servers and so on.  Whilst certain operating systems (Windows 7, Vista etc) can mask the association of the MAC to the IPv6 address, the ability for ISP's to perform continual, long term tracking of an individuals network activity is open for debate regarding privacy.

Many malware attacks today, are generally not directly focused on low level protocols.  Whilst many do, the larger area of interest for attackers, is that of higher level social engineering.  Attacks using spear phishing, camouflage downloads, USB drops and so on, allow for the proliferation of worms and viruses which are not directly referencing the underlying network protocols.  Does that mean IPv6 is safe from attack?  Perhaps not, but in the long term there is nothing to say it will be attacked more than IPv4.

There are several specific attacks already know to affect IPv6 networks.  A well known vulnerability concerns the ability to alter the routing header information.  A 'Type 0' attack, allows for a Denial of Service scenario to occur, between affected network hosts, as traffic oscillates between routing devices in a continuous loop.  Whilst this type of attack was possible to a limited extent in IPv4, the symptoms are considerably worse in IPv6 networks, as more devices can be impacted.  However, this is a well known vulnerability, identified and documented, resulting in the use of 0 based route header information to be deprecated.

One of the major practical security issues with IPv6, is the inability to effectively scan subnet ranges.  Whilst in IPv4, ranges where often less than 256 addresses in size, making enumeration quick and simple using out of the box scanners and scripts.  IPv6 subnets default to 2^64 devices in size, making a scan effectively impossible.  This can make asset identification difficult, especially if attempting to identify unauthorized devices.  However, this scanning argument could also be used as a security benefit.

One of the key issues with IPv4 was that that of ARP spoofing.  Whilst this technique will be less of a concern in IPv6 networks, it is instantly replaced by the new Neighbour Discovery Protocol spoofing.  Ultimately, it is envisaged that NDP spoofing will be mitigated by a secure implementation of NDP, cunningly called SeND, which utilises cryptography.

Whilst there will be obvious new attacks specifically related to IPv6, over time legacy IPv4 issues will be removed and as more nodes join the IPv6 world, it would be envisaged that more vulnerabilities will be identified and ultimately fixed.

Implementation Approach


As with any large scale implementation of a new technology, phased deployment would be recommended.  This however, provides several obvious issues.  IPv6 and IPv4 networks are not interoperable.  Whilst this can be overcome with tunnelling and translation tools, this is another complex configuration step for network administrators.  Whilst this is possible, the tunnelling approaches can break existing firewall, IDS/IPS tools, resulting in less than obvious security loop holes.

Existing IPv4 security tools and processes main not easily port across to IPv6.  They will need to be checked and ported or reconfigured to support IPv6 addresses.  This too would be an administrative overhead, which could require retraining costs.

Many newer network devices and operating systems (thinking Vista, W7, W8) will have IPv6 enabled by default.  If an organisation has not started an IPv6 implementation project, they could, probably, quite rightly, assume that no IPv6 traffic would exist on their networks.  This could be far from the truth.  Detection of existing IPv6 nodes and traffic would be an initial starting point in helping to understand the existing coverage of IPv6.

Like any new technology, implementation issues will always occur, but the long term landscape will contain nothing but IPv6 networks, so organisations need to start, planning, testing and implementing, as a necessity not a choice.

@SimonMoffatt