Asus Configuration File Decoder

All modern DSL routers provide an option to save the configuration of the device to a file on your computer so you have a backup if the router needs to be reset.

Asus WLAN DSL routers, like the RT-10N or RT-N14U (both of which I have owned and tested), unfortunately save their configuration backup files in encoded form (it's not really encrypted, they mostly obfuscate the content to prevent you from seeing what it is). This is rather annoying as it prevents users from legitimately looking at their saved configuration files and extracting information from it (in particular forgotten router passwords).

Over the years, the obfuscation methods changed. An old method was based on code present in the Linux kernel, newer models use a home grown obfuscation. See Pawit Pornkitprasan's GitHub for a nice writeup on the newer format and a python based tool similar to this one.

Fortunately, the code for the firmware of these routers is open source (old version) and open source (new version), as it is mostly based on Linux. So I created this tool ("asinus") to decode the backup configuration files of Asus routers like the RT-N10 (old) and RT-N14U (new). You can use the online form to upload your configuration file and see its content decoded right here.

If you are a more advanced user, you can also download the source code of the tool to decode the plain text from your old or new saved configuration. It also allows encoding in both formats, this way you can also modify the configuration file and then load it back onto your router. All you need to do to compile is type cc -o asinus asinus.c.

Decode Configuration File

I do not store or analyze your configuration file beyond decoding it and sending the content back to you. However, you should not belive me (or anyone else claiming things like that). So if you use the web form, you should afterwards change your passwords stored in the router configuration to make sure they remain secret.