The HTTP server in AsusWRT has a flaw where it allows an unauthenticated client to perform a POST in certain cases. This can be combined with another vulnerability in the VPN configuration upload routine that sets NVRAM configuration variables directly from the POST request to enable a special command mode. This command mode can then be abused by sending a UDP packet to infosvr, which is running on port UDP 9999 to directly execute commands as root. This exploit leverages that to start telnetd in a random port, and then connects to it. It has been tested with the RT-AC68U running AsusWRT Version 188.8.131.52.380.7743.
AsusWRT LAN Unauthenticated Remote Code Execution
AsusWRT Router Remote Code Execution
AsusWRT Router 184.108.40.206.380.7743 - LAN Remote Code Execution
ASUS Patches Root Command Execution Flaws Haunting Over a Dozen Router Models
UPDATED VERSION: RouterSploit 3.4.0
AsusWRT Router < 220.127.116.11.380.7743 - LAN Remote Code Execution