The article seems to cover two things here:
- Brute force "vulnerability".
- Unauthenticated DoS.
The former seems to be the focus, but it is hardly the most shocking of the two. You can always do a brute force key search with any captured data, and one would assume that, being DES, it is at least 56 bits. The unauthenticated DoS, however, presents a serious flaw.