[OpenWrt-Devel] OpenWRT www version banner a security risk

Daniel Dickinson openwrt at daniel.thecshore.com
Sun Sep 13 16:04:19 EDT 2015

I do think allowing to choose to disable the banner is a minor benefit, 
however, as I've said, there are much more effective means of preventing 
accidential exposure, and quite frankly if the user is *choosing* to 
open the web interface I think an warning and disabling the banner if 
the user foolishly insists on opening the interface despite the warning 
is more useful thank disabling the banner by default.

If you're going to argue it prevents against internal threats than I 
would argue that if your internal network is hostile enough that you 
need to worry about attacks on openwrt from your internal network AND 
you're not skilled enough to limit access to LuCI (or better, build an 
image without LuCI and just use SSH) to the specific trusted hosts 
(preferably by combination of MAC address and IP address) in the 
firewall, or (better) to use a 'management' VPN or VLAN that only 
trusted hosts can get on, then you're in a lot more trouble than 
eliminating the banner for LuCI will solve.



On 2015-09-13 10:21 AM, MauritsVB wrote:
> At the moment the OpenWRT www login screen provides *very* detailed version information before anyone has even entered a password. It displays not just “15.05” or “Chaos Calmer” but even the exact git version on the banner.
> While it’s not advised to open this login screen to the world, fact is that it does happen intentionally or accidentally. Just a Google search for “Powered by LuCI Master (git-“ will provide many accessible OpenWRT login screens, including exact version information.
> As soon as someone discovers a vulnerability in a OpenWRT version all an attacker needs to do is perform a Google search to find many installations with versions that are vulnerable (even if a patch is already available).
> In the interest of hardening the default OpenWRT install, can I suggest that by default OpenWRT doesn’t disclose the version (not even 15.05 or “Chaos Calmer”) on the login screen? For extra safety I would even suggest to leave “OpenWRT” off the login screen, the only people who should use this screen already know it’s running OpenWRT.
> Any thoughts?
> Maurits
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