IPv6 unmasking via UPnP

Martin Zeiser and Aleksandar Nikolich authored this post

EXECUTIVE SUMMARY

With tools such as ZMap and Masscan and general higher bandwidth availability, exhaustive internet-wide scans of full IPv4 address space have become the norm after it was once impractical. Projects like Shodanand Scans.io aggregate and publish frequently updated datasets of scan results for public analysis, giving researchers greater insight into the current state of the internet.

While IPv4 is the norm, the use of IPv6 is on the rise. However, there’s been very little analysis on the most recent version of the internet protocol because it’s impossible to run exhaustive scans given the size of the address space. We need to deploy novel techniques to enumerate active IPv6 hosts.

In the following post, we’ll present a technique that uses the properties of the Universal Plug and Play (UPnP) protocol to get specific IPv4 hosts to divulge their IPv6 address. This allows us to enumerate a particular subset of active IPv6 hosts which can then be scanned. We performed comparative scans of discovered hosts on both IPv4 and IPv6 and presented the results and analysis. Our findings show that this technique is valid and that there are significant security discrepancies in filtering between IPv4 and IPv6 interfaces of these hosts and unintended IPv6 connectivity will be a growing problem.

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