DNSSolutions

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The flaw discovered by Dan Kaminsky put a forthright scare into the entire internet community — and it should have. This attack, which is trivial in nature, could make the difference between sending all your private data to the secure server across the ocean, or to a happy hacker filling his/her eye balls with goodies.

But now, since everyone was woken up, there are two mainstream, proposed solutions in hopes of ending the insecurity in DNS: DNSSEC and DNSCurve. Which one should you bet your network’s integrity on? Better hope your patched or you might get bailiwicked. Let the enlightenment begin.

DNSSEC, or Domain Name System Security Extensions, is a suite of IETF specifications for securing certain kinds of information in DNS. Recently, lots of companies have been gearing up to implement DNSSEC, as a means of securing DNS on the Internet. One man, that opposes DNSSEC, has written his own code to provide a nicer, more secure solution, and far better than DNSSEC. He calls it DNSCurve.

DNSCurve uses high-speed, high-security elliptic cryptography to improve and secure DNS. Daniel J. Bernstein, the creator of DNSCurve and many other high security servers such as qmail and djbdns servers, doesn’t want DNSSEC implemented, but DNSCurve instead. And it is no question which one is the better choice after looking at the comparisons Bernstein makes between the two now rivals.

Some huge advantages with DNSCurve vs DNSSEC are encrypting DNS requests and responses, not publishing lists of DNS records, much stronger cryptography for detecting forgeries, (some) protection against denial of service attacks, and other improvements.

There is one quick, unrelated issue that I disagree with Mr. Bernstein about. After offering $500 “to the first person to publish a verifiable security hole in the latest version of qmail”, he states: “My offer still stands. Nobody has found any security holes in qmail”. But in 2005, Georgi Guninski found one and has confirmed exploitability on 64 bit platforms with a lot of memory.

Bernstein denied his claim and then stated “In May 2005, Georgi Guninski claimed that some potential 64-bit portability problems allowed a “remote exploit in qmail-smtpd.” This claim is denied. Nobody gives gigabytes of memory to each qmail-smtpd process, so there is no problem with qmail’s assumption that allocated array lengths fit comfortably into 32 bits.”. Now, to me, and I am sure to many other people as well, an exploitable bug in an exploitable bug. Conditions have to sometimes be met and “can be carried too far”, one might put it, but in this case, it is clear that Guninski found at least one exploitable bug in qmail. Game over. No disrespect to Mr. Bernstein or his code; he does have both great code and concepts. On with my main literature.

So, if I were a betting man (and I am), I would gamble on Bernstein’s all around great approach to making DNS safer, more resilient against attacks, and definatly more secure. Hopefully, people will realize money can’t solve all our problems, but the guys that know what they are doing, can, and might just make some things happen pretty soon.

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