Comment 5 for bug 673366

Revision history for this message
C Snover (launchpad-net-zetafleet) wrote :

Oops, I made a typo in the original report. Sorry!

The speed of log writing in our scenario (with about 1600 concurrent connections) was 17MB/sec, not 1MB/sec. As such, I still feel like this is a potential security issue, since it appears that it is trivial for even low levels of traffic to nginx to quickly exhaust a server’s disk space. A single, malicious attacker could easily cause unrelated applications to crash/corrupt data just by opening a couple thousand connections to a server and waiting for nginx to fill up the disk.

If the speed of the log writing increases with the number of connection attempts (1 alert per connection), fewer than 4000 connections could cause 100MB/s of log data to be written, resulting in disk space exhaustion on an 80GB disk in under 14 minutes. In our case, with 1600 connections, disk space would have run out in about 75 minutes if we hadn’t managed to catch it quickly.