C.6. Conclusion

The preceding sections describe the bulk of the publicly available data on the frequency, size, duration, and character of DDoS attacks. (More data exists from studies that are not available to the public.) Much of it is a few years old. There is only one group known to the authors to be doing continued backscatter analysis using an unused /8 network over a long period of time (see http://monkey.org/~jose/presentations/ddos.d/). Similar sources of data have not been widely available to date, and this has made research very difficult to pursue. This situation is expected to change as a result of an HSARPA-funded project to collect various types of data for analysis and testing purposes. (See http://www.computerworld.com/securitytopics/security/story/0,10801,96011,00.html)

But it is a fair bet that attacks are no less common. It is clear, as well, that the sophistication of attacks is increasing. The data from these various studies also make clear that DDoS attacks target a wide range of systems, from home users on dial-up lines, to large businesses, to important pieces of the Internet's infrastructure.