Frankly, yes. The basic concepts of a DNS server are fairly straightforward, but as demonstrated by this attack, the devil is in the details. This attack uses reasonably advanced cryptanalysis, and exploits the predictable behaviour of DNS clients. I suspect that this attack would also have been mitigated by the use of DNSSEC, but the roll-out of that has been held up for years - and DNSSEC itself introduces even more cryptographic complexity.