MAC Address Randomization: Not as Random as You Think

MAC Address Randomization: Not as Random as You Think

For privacy-minded individuals, randomization of Media Access Control (MAC) addresses for Wi-Fi networks and mobile devices has long been touted as a standard defensive technique. However, recent research [1] suggests that major flaws in implementation have left smartphone users defenseless and vulnerable to exploitation.

What is MAC Address Randomization?

All network interfaces on networked devices have a factory-assigned MAC address which is hard-coded on a network interface controller. In the case of smartphones using 802.11 (Wi-Fi) radio specifications, [2] devices have a 48-bit link-layer MAC address that functions as a globally unique identifier. The MAC address is sent in every link-layer frame sent to or from the mobile device. [3]

Smartphone behavior is distinct from general computing network cards (both wired and wireless), as the MAC address used to assign an address to your computer on the local network is not passively sent to computers beyond the local router. This means the MAC address is not traceable unless logged by other computers on the network. [4]

Smartphone behavior has grave privacy implications. Any network observer can eavesdrop on nearby Wi-Fi traffic, with pinpointing of this traffic to a uniquely identified device. [6] In addition to broadcasting of the MAC address ID, smartphones send probe requests that broadcast at a semi-constant rate, posing an even greater surveillance risk: [7]

… wireless devices identify access points within close proximity. Traditionally, devices perform active scanning where they broadcast probe request frames asking nearby APs to identify themselves and respond with 802.11 parameter information required for connection setup. These probe request frames require a source MAC address, but if an 802.11 device uses its globally unique MAC address then it is effectively broadcasting its identity at all times to any wireless receiver that is nearby. Wireless device users can then easily be tracked across temporal and spatial boundaries as their devices are transmitting with their unique identity.

In an attempt to solve this problem, most major smartphone device manufacturers and operating systems (Android, iOS etc.) have implemented protocols to create temporary, randomized MAC addresses that are distinct from the true global identifier. Randomized, pseudonym addresses are changed periodically to restrict third party tracking. [8]

In theory, observers of network traffic (like ISPs) should be prevented from singling out smartphone traffic or identifying the physical location from other nearby devices, because randomized MAC addresses shouldn’t be linkable to the previous address. [9]

The Flawed MAC Address Randomization Implementation

Transportation of network traffic without a static ID is a common sense approach for privacy advocates. Unfortunately, a recent study by the US Naval Academy shows the implementation of this technique in smartphones is seriously flawed across every OS platform, device manufacturer and model.

Using real-world datasets, the 2017 study found: [10]

  • Randomization techniques and schemes were easily identified from large collections of wireless traffic.
  • Adoption rates for MAC randomization are low, particularly for Android devices. [11]
  • Passive and active techniques for determining true global identifiers is a trivial task due to flawed MAC randomization implementations, particularly for Android devices. [12]
  • The global MAC address was discoverable via a “control frame attack”. This allows tracking/surveillance for all known devices, irrespective of the OS, manufacturer, device type or randomization scheme.

Smartphone chipsets were discovered to have a flaw in how they handled low-level control frames, allowing an identification rate of 100%. Considering previous studies exhibited “only” a 50% accuracy rate, and Android devices were susceptible even when Wi-Fi was disabled or Airplane Mode enabled, this is a devastating result for user privacy. [13]


Unfortunately, smartphone MAC address randomization policies are not universally adopted, nor particularly effective at eliminating privacy risks. Network adversaries currently have a smaller test set to contend with, making their job of identification easier. [14]

Standardized MAC address randomization needs to be correctly implemented on any mobile device using Wi-Fi, with the entire length of the MAC field used as randomization input. Unique methods of randomization simply increase the attacker’s chances of deanonymizing a user. [15]

Other critical changes for smartphone user privacy include: [16] [17]

  • Random addresses for every probe request.
  • Removal of sequencing numbers from probe requests.
  • Removal of global MAC addresses from probe requests.
  • Elimination of directed probe requests for cellular offloading.
  • Redesign of chipset firmware to prevent RTS frames eliciting a CTS response while in State 1.

Convincing device manufacturers to implement MAC address randomization consistently across all devices is a large and improbable undertaking. [18] Without a solution on the horizon, users of mobile devices should expect to be uniquely fingerprinted. User behavior on mobile devices should be adjusted accordingly in response to this clear and present danger to user privacy.

Primary Source

Martin, J. et al. (2017). “A Study of MAC Address Randomization in Mobile Devices and When it Fails”. US Naval Academy.

  4. Unfortunately, due to weaknesses in current spoofing methods it is likely the MAC address can be enumerated via the physical characteristics of the Wi-Fi card.
  5. Spoofing is only necessary if you expect to travel with your laptop or PC. It is not required for home PCs that do not change locations. For further information on spoofing MAC addresses in Whonix, see
  11. Possibly due to chipset and firmware incompatibilities.
  12. Notably, Samsung devices were never observed to perform MAC randomization, despite being the leading manufacturer of Android devices.
  17. See the original paper for further discussion of these issues.

Livestream NOW!

Patrick and I are going stream ourselves NOW under this address:

If you’d like to join us, we’d be very grateful. Furthermore, this will be our first Patreon Stream. If you want to support us on Patreon, click here.


Remember that to watch the stream via the Tor Browser Bundle, you should set the Security Settings to Low (default).


Also, if you would like to talk to us or ask us a question, you may either post it in this thread, ask directly via the Youtube Chat or join us via OTR. To join us via OTR, simply sent a message to via OTR.

Public Livestream on 14th of April at 8PM CEST and Patreon

Whonix is a project which requires a lot of dedication, passion and time to be properly maintained. Especially Patrick has sacrificed a huge part of his live to making a fail-safe way to use Tor accessible to as many people as possible.

For the last few years, he mainly was able to focus on the tasks required to maintain Whonix thanks to the dedication of individuals supporting Whonix either in the forum, wiki, on Github or on all three, as well as the occasional donations provided by generous donors. However, because of the nature of these donations, it continues to be challenging to focus on long time goals, seeing how it is hard to make extensive plans based on occasional monetary support.

Because of this, over the course of the last few months, we have looked into different ways of obtaining long term funding, either via government programs or by incentivising people to donate on a more regular basis. In the end, we decided to look into the latter, as it would enable us to have an even better communication with our community, wouldn’t in any way compromise the open and rather democratic structure currently in place for support and development and make it possible to give something back to our most generous supporters. It also would keep Whonix in the hands of our great community, instead of trusting a government organisation which may have different goals or requirements and would potentially force us to not act in the best interest of our users, by limiting our ability to implement the features we deem necessary.

To make this possible, we decided to team up with Patreon, a service which enables you to donate a certain amount of money every month. You are able to cancel your regular donation anytime you want and, best of all, will receive certain rewards by us if you decide to donate. These rewards all have the goal of both giving you an incentive to donate a bit to keep Whonix sustainable for the future and furthering the cause behind Whonix in general. You will be able to more directly decide on new features and may gain access to other rewards, like a monthly live stream in which Patrick Schleizer and I, Ego are going to cover certain topics related to Whonix, Tor, anonymity, journalism and cryptography, as well as answer question of Patrons.

Our complete list of rewards:


  • $1 Become A Patron
  • $5 Join the Monthly Livestream
  • $10 Priority Support
  • $15 Livestream Chat Access
  • $20 Immortalize yourself by becoming part of the Whonix Installer Source
  • $30 Vote on Features
  • $50 Personal Support
  • $100 Personalized Video Guide
  • $500+ Advertise on


Now, I am aware of what some of you may think right now.

Isn’t Patreon a service which requires the use of something traceable like a credit card or PayPal and don’t they use Cloudflare, the enemy of all Tor users?!

Yes, that is correct. Because of the fact that a lot of Whonix users are rather critical of services using Cloudflare, it was important for us to address this head on. Obviously, we can understand that a lot of users will not be able to use Patreon due to the fact that they require to stay as anonymous as possible. We understand that and will never ask someone who needs to stay anonymous to give up that anonymity, simply so we may get some cash. We also will continue to focus on keeping this subset of our user base, the one that really requires anonymity, as safe as possible.

If you are a user who has no issues with using a service like Patreon, would like to support Whonix and are able to do so, we would be very grateful if you could do so via a monthly donation.

Since it is quite a lot to ask you for money when you aren’t sure whether you will enjoy the rewards, we have decided to make our first monthly Whonix-Livestream open to anyone. It will be broadcasted via Youtube Live which you may access via the Tor Browser Bundle with Whonix and you may ask Patrick and me anything you’d like via OTR.

To join our livestream, simply visit Youtube via this link on Friday, the 14th of April at 8PM Central European Summer Time:

For our American users, that would be 2PM Eastern Time. If you click on the link, there is also a timer to show you when the stream will start.

We hope to see many of you join our stream. If you miss it, you will be able to watch it later on our Youtube Channel were every stream will be publicly available after the fact.

In conclusion, we hope that you will enjoy using Whonix for years to come and would be thankful for any support, no matter how small.

Our Patreon may be found here:

Tor Stable Upgrade – Testers Wanted!

Updated Tor was uploaded to Whonix stable-proposed-updates as well as to testers repository.

Instructions for changing Whonix repository:

Then just do a update:

Announcing unMessage: a Next-Gen Tor Messenger

unMessage is an anonymous messenger that uses Tor to hide metadata of participants. Its still in early development, however a major new feature such as Tor-to-Tor audio chat (the first such implementation we are aware of) has been included. Major additions like file-sharing support, video conferencing and a portable code-base for mobile platforms are planned.

Their major goal is to provide a better UX and a competitive feature set to move users away from proprietary solutions that don’t respect privacy. Its not ready for mass adoption yet, so only the more technical audience among you should go ahead try it out. Feedback and/or pull requests are highly appreciated.

Check it out on Github:

Tor Stable Upgrade – Testers Wanted!

Tor was updated to in Whonix stable-proposed-updates as well as in testers repository.

Instructions for changing Whonix repository:

Then just do a update:

[Release] Whonix-Installer and UI

Disclaimer: Please remember that Windows is NOT a secure host operating system for a variety of reasons. This Installer was mainly created to make it easy for people to experience Whonix first hand without the requirement of installing an entirely new OS. Under no circumstances, use Windows for sensitive work.


After almost a year of active development, we are releasing the Whonix-Installer which will provide a simple and familiar way for Windows users to gain access to Whonix and its massive capabilities as well as toolset.

Currently, the Whonix-Installer for Windows is based on nsisbi, a fork of the often used “Nullsoft Scriptable Install System”, which was required to circumvent the general size limit of 2Gb usually enforced by “NSIS”. Even with that though, a bit of additional modification was required to include all the files required for Whonix into one simple to use “.exe file”. That’s why for the foreseeable future, a disk-space of 8Gb is required during installation, as the Gateway and Workstation required additional compression, since even “nsisbi” has a single file size limit of 4Gb. Thus, during installation, both Gateway and Workstation take temporarily double the disk space, during the decompression process.

Adding to this however, the Whonix-Installer can be used regardless of whether you’ve installed VirtualBox previously or not. Any older virtual machines should be unmodified by using the Whonix-Installer.

Furthermore, a small, simple user interface, named “Whonix-UI” or alternatively “Whonix for Windows”/”Whonix.exe” has been created to make starting and terminating of both the Gateway and Workstation as simple as possible. It is still very much in the early stages of its development, which is part of the reason for its rather basic appearance though functionally works as intended. By pressing the “Start Whonix Button”, both the Gateway and Workstation are launched and by pressing the “Stop Whonix Button” they are terminated. While Whonix is being used, the window prevents itself from being closed, as to prevent issues.

If you’d like to try the UI with your existing installation of Whonix, you may simply drag-and-drop it into the folder in which you’ve installed VirtualBox.

Download Links:

The Whonix-Installer may be downloaded from here:

The Whonix-UI can be found separately here:

Tagged with: , , ,

Whonix featured on Tor blog

Whonix stable upgrade released!


Either start with fresh templates. I.e. uninstall qubes-template-whonix-gw and qubes-template-whonix-ws. Then, to install, run in dom0:

sudo qubes-dom0-update --enablerepo=qubes-tempates-community qubes-template-whonix-gw qubes-template-whonix-ws

Or you can also upgrade from Whonix’s repository. Please refer to the following instructions:


Or you can also upgrade from Whonix’s repository. Please refer to the following instructions:

major Whonix 13 -> changes:

How to upgrade Debian, Whonix, etc. without being compromised by CVE-2016-1252