August 23, 2021

Zoom RCE from Pwn2Own 2021

On April 7 2021, Thijs Alkemade and Daan Keuper demonstrated a zero-click remote code execution exploit in the Zoom video client during Pwn2Own 2021. Now that related bugs have been fixed for all users (see ZDI-21-971 and ZSB-22003) we can safely detail the bugs we exploited and how we found them. In this blog post, we wanted to not only explain the bugs and our exploit, but provide a log of our entire process.

June 30, 2016

StartEncrypt - obtaining valid SSL certificates for unauthorized domains

Recently, we found a critical vulnerability in StartCom’s new StartEncrypt tool, that allows an attacker to gain valid SSL certificates for domains he does not control. While there are some restrictions on what domains the attack can be applied to, domains where the attack will work include,,, and others.