CVE-2019-25015: Security Advisory 2019-11-05-1 - LuCI stored XSS

A vulnerability has been reported in LuCI which allows injection of script code through maliciously crafted wireless network SSIDs.

When joining a wireless network by clicking Network → Wireless → Join, the subsequent configuration view interprets the SSID of the network to join without proper escaping, allowing to execute arbitrary JavaScript in the client’s web browser through network names which contains payload, for example AP</h2><svg onclick=alert(0);>

Additionally the network interface overview displays configured wireless network SSID without proper escaping.

Since the SSID string is stored in the UCI configuration, the issue effectively becomes a stored Stored Cross Site Scripting (XSS) vulnerability.

In order to exploit this vulnerability, a user needs to either explicitly pick a network with a malicious SSID from the wireless scan result list or manually add a wireless network with an SSID containing embedded script and browsing to the network interface overview page.

The wireless scan result list is not affected by this issue, so no automatic script code execution is possible through it.

To fix this issue, update the affected LuCI package using the command below. The fix is contained in version git-19.309.48729-bc17ef673 and later.

opkg update; opkg upgrade luci-mod-admin-full

To workaround the problem, avoid joining networks with HTML code in the SSID.

To our knowledge, LuCI packages with OpenWrt versions 18.06.0 to 18.06.4 are affected. OpenWrt 19.07 is not affected by this problem. The fixed LuCI packages are integrated in the OpenWrt 18.06.5. Older versions of OpenWrt (e.g. OpenWrt 15.05 and LEDE 17.01) are end of life and not supported any more.

The issue has been reported by Marcin Zieba <marcin.zieba at ehlo.red> on 27th October 2019 and independently by Ridwan Maulana <mrm at asdqwe.net> on 5th November 2019.

The issue has been fixed by Jo-Philipp Wich <jo at mein.io>