This is a quick script to redirect a wireless client to a fake a login page for a WLAN. This is much stealthier than implementing a rouge AP in conjunction with layer 1/2 attacks against the WAP. It uses tethereal to listen for IP addresses being assigned to a new wireless client via DHCP, then runs dnsa-ng to redirect DNS queries from the new client to the specified IP.
You can download it from the following link: https://packetstormsecurity.com/files/download/40313/wlan_webauth.txt
Source: https://packetstormsecurity.com/files/40313/wlan_webauth.txt.html