Category: Unbound

DNS Security Advisories Out Today For BIND, PowerDNS and Unbound – Time To Upgrade!

DNSWhile this has nothing to do specifically with the topic of DNSSEC that we cover here on Deploy360, there is important news in the broader world of “DNS security”.  The vendors of three of the major DNS recursive resolvers today released security advisories about a particularly nasty bug where the resolver can be tricked into trying to follow essentially an infinite loop and wind up exhausting all resources and potentially shutting down.  The advisories from BIND, PowerDNS and Unbound are found at these links:

The advisories from both PowerDNS and Unbound indicate that this bug would be difficult for an attacker to exploit unless they were within the user base of the recursive resolver.  The BIND advisory is more open-ended and indicates the bug could be executed remotely.

In all cases the easiest solution is to upgrade to the newest versions:

While there are apparently no known exploits of the bug in the wild yet, that will now only be a matter of time.  It would be best to upgrade your recursive resolvers as soon as possible.

P.S. While you are in there updating your DNS resolver, if you are using BIND or Unbound, why not enable DNSSEC validation?  It’s a simple change in the configuration file, as shown in this SURFnet white paper.

Weekend Project: Add DNSSEC Validation to an OpenWRT WiFi Device

Looking for a weekend project?  Do you use a WiFi access point based on OpenWRT?

If so, here are some quick instructions about how to install the Unbound DNS resolver that supports DNSSEC validation into OpenWRT.  What this will do is change the DNS resolver in your access point to start performing DNSSEC validation… so as more domains get signed you’ll be able to know that you are, in fact, getting to the correct domain. Plus, with DNSSEC validation available you’ll be able to start playing around with very cool new technologies like the DANE protocol… who knows what you’ll be able to do with it!

The great thing is that it turns out to be a trivial process, which is great to see!

P.S. While you’re hacking on your devices, check out some of the other DNSSEC tools we are listing…