Haller: MAC Address Spoofing in NetworkManager 1.4.0

[Posted August 30, 2016 by ris]

We recently pointed to Lubomir Rintel's coverage of NetworkManager 1.4. Thomas Haller follows up with a more detailed look at the MAC spoofing capabilities of NetworkManager. "1.2.0 relies on support from wpa_supplicant to configure a random MAC address. The problem is that it requires API which will only be part of the next major release 2.6 of the supplicant. Such a release does not yet exist to this date and thus virtually nobody is using this feature. With NetworkManager 1.4.0, changing of the MAC address is done by NetworkManager itself, requiring no support from the supplicant. This allows also for more flexibility to generate “stable” addresses and the “generate-mac-address-mask”. Also, the same options are now available not only for Wi-Fi, but also Ethernet devices."

Haller: MAC Address Spoofing in NetworkManager 1.4.0

Posted Aug 30, 2016 20:15 UTC (Tue) by dkg (subscriber, #55359) [Link] (1 responses)

I commented on the earlier article about NM's default removal of lower-layer MAC address spoofing (e.g. by udev). I encourage network-manager to switch the default for ethernet.cloned-mac-address back to preserve!

Haller: MAC Address Spoofing in NetworkManager 1.4.0

Posted Aug 31, 2016 13:36 UTC (Wed) by ovitters (guest, #27950) [Link]

Seems they agree with you! Hopefully this gets into the next stable release.

Btw, gave you some additional permissions on bugzilla.gnome.org. Useful for eh.. triage bugs?

Haller: MAC Address Spoofing in NetworkManager 1.4.0

Posted Sep 1, 2016 13:07 UTC (Thu) by joey (guest, #328) [Link] (1 responses)

I tried following this guide, and the first thing I did was set the global wifi.cloned-mac-address=random. However, that turned out not to cause a random mac to be used. It seems that each of my wifi devices that I'd used with network manager before had its own wifi.cloned-mac-address=permanant setting, so I had to override it on a per-device basis.

Also, there exist some wifi drivers that ignore attempts to change the mac address. Network-manager seems to not show any indication when it fails to randomize it. r8723au is the module I know of with this problem (I earlier fixed macchanger to notice and warn when this happens).

I hope this gets exposed in the nm-applet GUI, because mac randomization should be available to everyone, not only the few people who will read this nice guide and work through the gotchas.

Haller: MAC Address Spoofing in NetworkManager 1.4.0

Posted Sep 1, 2016 13:09 UTC (Thu) by joey (guest, #328) [Link]

Actually, it has to be overridden on a per-connection-per-device basis, at least for anywhere that device has been used before. Urk.