Botnet

We previously wrote in detail about how botnets hammering a web site can cause outages.

Here is another case that emerged in the past month or so.

Again, it is a distributed attempt from many IP addresses all over the world, most probably from PCs infected with malware.

Their main goal seems to be to add content to a Drupal web site, and trying to register a new user when that attempt is denied because of site permissions.

The pattern is like the following excerpt from the web server's access log.

We had a site for a client that was stable for close to two years, then suddenly started to experience switches from the master to the geographically separate slave server as frequently as twice a week.

The site is an entertainment news site, and its articles get to Google News on occasions.

The symptoms was increased load on the server, a sudden influx of traffic causing over 800 simultaneous connections all in the ESTABLISHED state.