NVRAM Dump: Sensitive Information Redaction

[gatorback]

As I understand it, the command:

NVRAM show
​

can provide useful troubleshooting information when provided to the community (via pastebin). Examples of potentially security-sensitive information include:

ddns_hostname
sshd_dsskey

Originally, I thought it would be good to list items to be removed from the output file, but perhaps the better (from a security standpoint) approach is to explicitly extract non-sensitive to a pastebin file. Does a script to perform the latter exist? Is there a better process / best practice?

 

[thelonelycoder]

As I understand it, the command:

NVRAM show
​

can provide useful troubleshooting information when provided to the community (via pastebin). Examples of potentially security-sensitive information include:

ddns_hostname
sshd_dsskey

Originally, I thought it would be good to list items to be removed from the output file, but perhaps the better (from a security standpoint) approach is to explicitly extract non-sensitive to a pastebin file. Does a script to perform the latter exist? Is there a better process / best practice?

Admin account name and Password is also part of that.

 

[gatorback]

Thank you. Excellent reply: I look forward to good replies.

 

[thelonelycoder]

I just wanted to mention it, as it may not be obvious to other readers.

 

[ColinTaylor]

Admin account name and Password is also part of that.

Indeed. These also contain important passwords, especially as people use the same password for different services:

acc_list
http_passwd
pptpd_clientlist
wl*_wpa_psk
vpn_client*_password
vpnc_pppoe_passwd
wan*_pppoe_passwd

 

[RMerlin]

Asus implemented something similar already, which they use to remove security-sensitive information before sending back other nvram settings to them whenever you use their Feedback form (don't look for that page tho, I remove it from my firmware, as I don't want feedback/bug reports about my firmware being sent to them). Not sure if that list is complete (for starter it seems to be missing some VPN credentials), but it would be a starting point for anyone wishing to create such a script.

https://github.com/RMerl/asuswrt-merlin/blob/master/release/src/router/nvram_arm/main.c#L51

 

[cybrnook]

wps secret key
serial number
and why not, MAC addresses

 

[peraburek]

is it possible to get serial number of ASUS router from command line interface (SSH or telnet) ?

I have tried nvram show but I don't see it