Over the last couple of days my servers have been suddenly getting extremely slow and non-responsive at times. The system load averages climb to the hundreds and nothing responds. This has lasted from a few minutes to a few hours (the night before last). I found nothing out of the ordinary coming into the system and was having trouble figuring out the source of this DoS, until late last night. I was watching the server logs while working on some code and noticed that I was getting referer spammed. As I continued to look (and log) in amazement, a handful of machines made a large number of requests to my server, all with the tell tale referer spam clues (there were about 10,000 total requests in that attack). My understanding is that when the spammer requested such a large number of pages in quick succession, the server buried itself in […]