Vietnamese authorities orchestrate DDoS attack against Viet Tan website

August 22, 2011

Beginning on August 13, hackers launched a sustained attack against A network of compromised computers, or botnet, consisting of 77,000 internet protocol (IP) addresses were employed in the distributed denial-of-service (DDoS) operation. Of the 77,000 IP addresses, 73% originated from Vietnam. These Vietnam-based IPs belonged to many different local internet service providers (ISPs).

Like many other pro-democracy websites, has been constantly blocked by Vietnamese authorities. To access Viet Tan’s website, internet users from Vietnam would have to use proxies or other circumvention methods.

On August 13, however, the Hanoi government’s firewall on was lifted so that the botnet relying on computers from Vietnam could take down the Viet Tan website. This is further evidence that the communist authorities of Vietnam are behind the ongoing hacker attacks against pro-democracy websites and blogs.

These hacker attacks represent the Hanoi government’s policy of extending censorship from society to the online space. It shows how Vietnamese authorities are fearful of free speech and the democratizing power of social media.

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With so many computers in Vietnam infected by malware and unknowingly enlisted as zombies in DDoS attacks, ISPs in Vietnam have a responsibility to protect their customers. Local ISPs need to inform their customers of the botnet attacks and take measures to stop these abuses. A full list of the Vietnam-based IPs is available at

We are also publishing the IP addresses of computers from outside Vietnam which were abused for the DDoS attack: Internet users outside Vietnam who have been comprised should clean their computers and consider appropriate legal actions.

About Viet Tan

The mission of Viet Tan is to overcome dictatorship, build the foundation for a sustainable democracy, and demand justice and human rights for the Vietnamese people through a nonviolent struggle based on civic participation.