As a huge "denial of service" attack hit Avaaz's servers last week, we asked members to help fund our defences. They reacted brilliantly: over 42,000 have sent donations so far. In this interview with TechWeek, executive director Ricken Patel explains what happened – and Avaaz's strategy to defeat the cyber-hooligans. He answers some tough questions.

We've been expecting this for a while: the very same week, servers hosting a live stream from opposition activists in Russia suffered a similar attack. Such tactics are also familiar tools in the digital propaganda war being fought over Syria.

Here's Ricken Patel's full interview with TechWeek's Tom Brewster.