Researcher uses AWS cloud to crack Wi-Fi passwords

A security researcher has said he will release an open-source kit for cracking WPA-PSK keys using the Amazon Web Service cloud at a security conference next week.

Thomas Roth plans to release the Cloud Cracking Suite (CCS) on 19 January at the Black Hat security conference near Washington DC. The CCS can crack a WPA-PSK handshake at a speed of 400,000 attempted passwords per second using eight GPU-based Amazon Web Services (AWS) instances, Roth said on Thursday. WPA-PSK, which stands for Wi-Fi Protected Access, Pre-Shared Key, is a security authentication mechanism for Wi-Fi networks.

The time it takes to crack a password depends upon the password strength. "If [the password is] in a dictionary it'll be very fast, but if you have to brute force it and it's longer than eight characters and its complexity is okay, it'll take a very long time," Roth told ZDNet UK.

The CCS uses rentable machine infrastructure from AWS, focusing on the recently released cluster GPU instance. It is written in the Python programming language.

"I hope that people get a better feeling on how big the real impact of high-performance computing in the cloud really is," Roth said. "The best way for doing that and keeping track of new innovations in this area is to provide people with a framework that they can use and extend easily for further research on this topic."

The CCS will initially support cracking for SHA1, WPA and WPA2-PSK cryptography, all with Cuda support and acceleration, and offers experimental support for MD5 and NTLM.

In November, Roth demonstrated the cracking of the SHA1 hashing algorithm using an AWS cluster GPU instance.

AWS's cluster GPU instances use an HPC-bespoke networking architecture for fast inter-instance communication and contain Nvidia's Tegra Fermi-architecture GPUs. The Cuda instruction framework can increase the efficiency with which the Tegra GPUs are utilised.

Ccs-server and ccs-client
The CCS is composed of two parts — the ccs-server and the ccs-client. Ccs-server supervises the cracking of the passwords and co-ordinates with other AWS instances working on the job. Ccs-server is a software package that is loaded inside an Amazon Machine Image (AMI), which is then loaded into Amazon Web Services Elastic Compute Cloud (EC2).

Ccs-client is a command line program for managing the jobs.

There are other services that can crack WPA using rentable cloud infrastructure, such as WPACracker, which uses its processor cluster to use dictionary attacks to crack Wi-Fi passwords.

"Nothing in this researcher's work is predicated on the use of Amazon EC2. As researchers often do, he used EC2 as a tool to show how the security of some network configurations can be improved," an AWS spokesperson told Darkreading. "Testing is an excellent use of AWS; however, it is a violation of our acceptable use policy to use our services to compromise the security of a network without authorisation."