Imma Chargin Mah Lazer-How to protect against (D)DoS attacks

Denial of Service (DoS) attacks aim to make services and systems unavailable to legitimate users . If these attacks are performed by multiple sources at the same time and for the same target, they are called Distributed Denial of Service (DDoS) attacks. This talk “Imma Chargin Mah Lazer” describes different types of (D)DoS attacks that are out in the wild and are seen on a daily basis by different corporations. Furthermore,  a multi-layered strategy to mitigate such kinds of attacks has been presented within the talk. The speaker is Dr. Oliver Matula, an IT security researcher at ERNW who holds a PHD degree in physics. He presented the topic in a simple way which eases the delivery of information to audience of different technical levels and backgrounds.

Continue reading “Imma Chargin Mah Lazer-How to protect against (D)DoS attacks”

Continue reading

VMDK Has Left the Building — Denial of Service

Almost all of our presentations and write-ups on the VMDK File Inclusion Vulnerability contained a slide stating something like

“we’re rather sure that DoS is possible as well ;-)”

including the following screenshot of the ESX purple screen of death:

So it seems like we still owe you that one — sorry for the delay! However the actual attack to trigger this purple screen was rather simple: Just include multiple VMDK raw files that cannot be aligned with 512 Byte blocks — e.g. several files of 512 * X + [0 < Y < 512] Bytes. Writing to a virtual hard drive composed of such single files for a short amount of time (typically one to three minutes, this is what we observed in our lab) triggered the purple screen on both ESXi4 and ESXi5 — at least for a patch level earlier than Releasebuild-515841/March 2012: it seems like this vulnerability was patched in Patch ESXi500-201203201-UG.


Pascal & Matthias

Continue reading