Scrutinizing WPA2 password generating algorithms in wireless routers
Eduardo Novella Lorente, Carlo Meijer, Roel Verdult · 2015
A wireless router is a networking device that enables a user to set up a wireless connection to the Internet. A router can offer a secure channel by cryptographicmeans which provides authenticity and confidentiality. Nowa-days, almost all routers use a secure channel by default that is based on Wi-Fi Protected Access II (WPA2). This is a security protocol which is believed not to be sus-ceptible to practical key recovery attacks. However, the passwords should have sufficient entropy to avert brute-force attacks. In this paper, we compose a strategy on how to reverse-engineer embedded routers. Furthermore, we de-scribe a procedure that can instantly gather a complete wireless authentication trace which enables an offline password recovery attack. Finally, we present a number of use cases where we identify extremely weak password generating algorithms in various routers which are mas-sively deployed in The Netherlands. The algorithms are used to generate the default WPA2 password. Such a password is loaded during device ini-tialization and hardware reset. Users that did not explic-itly change their wireless password are most likely vul-nerable to practical attacks which can recover their pass-word within minutes. A stolen password allows an ad-versary to abuse someone else’s internet connection, for instance compromising the firewall, making a fraudulent transaction or performing other criminal activities. Together with the Dutch National Cyber Security Cen-tre we have initiated a responsible disclosure procedure. However, since these routers are also used by many other companies in various countries, our findings seem to re-late an international industry wide security issue. 1