ntopng 1.2.0 XSS injection using monitored network traffic ntopng is the next generation version of the original ntop, a network traffic probe and monitor that shows the network usage, similar to what the popular top Unix command does. The web-based frontend of the software is vulnerable to injection of script code via forged HTTP Host: request header lines in monitored network traffic. HTTP Host request header lines are extracted using nDPI traffic classification library and used without sanitization in several places in the frontend, e.g. the Host overview and specific subpages for each monitored host. The injected code might be used to execute javascript and to perform management actions with the user-rights of the current ntopng user, which can be used to disable the monitoring function or deletion of accounts making the monitoring system unusable. To give a coarse idea of the vulnerability the following python script can be used on the monitored network, afterwards the victim needs to browse to the Host overview / Host details in the ntopng frontend. import httplib conn = httplib.HTTPConnection("example.com") headers = {"Host": "<SCRIPT>alert(\"xss\")</SCRIPT>", "Accept": "text/plain"} conn.request("GET", "/", None, headers) r1 = conn.getresponse() print(r1.status, r1.reason) data1 = r1.read() Other users of the nDPI code might be affected as well. Steffen Bauch Twitter: @steffenbauch http://steffenbauch.de