|Router Security||Wi-Fi Protected Setup - WPS||
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Our Standard Operating Procedure isn't hard: we see an available Wi-Fi network, click on it and enter the password. Yet, back in 2007 this was deemed too hard, so WPS was introduced to make Wi-Fi access easier.
The WPS protocol in consumer routers is like putting a virtual HACK ME sign on the box. WPS was a bad idea to being with, has a huge design flaw, comes from an unstrustworthy source and is overly complicated. In addition, there have been multiple instances of poorly written, buggy implementations.
It is better to use a router that does not support WPS at all. If your does, try to turn it off, then verify that it really is off using the software mentioned near the end of this page.
A typical consumer router supports WPS, a typical business class router does not. My favorite router, the Pepwave Surf SOHO, does not support it. A March 2017 article in PC Magazine, The Best Wi-Fi Mesh Network Systems of 2017 describes nine different mesh router systems. Six of the nine do not support WPS, which I take as progress considering that the devices are targeted at consumers. The three that do support WPS are the Netgear Orbi, Amped Wireless Ally and Luma.
You have to wonder if the design of WPS stems from incompetence or if it was intended for spying. Arguing on the side on incompetence, is that WPS comes from the WiFi Alliance, the same group that gave us WEP encryption.
A visitor to your home/office illustrates one aspect of why WPS is a bad idea The visitor only needs to turn your router upside down, take a cellphone picture of the label on the bottom and they can, thereafter, get into your WiFi network. The WPS password (they use a different term, but its a password) on the router label is the equivalent of a get out of jail card in Monopoly. It over-rides the WPA2 password.
Have a really long WPA2 password? It doesn't matter, WPS lets the visitor in anyway. Change the WPA2 password every week? It still doesn't matter, WPS continues to let the one-time visitor into your network.
But, a visitor with a cellphone is only part of the security problem with WPS.
There are multiple modes of operation in WPS. Only one has an obvious security flaw but routers, as a rule, do not support enabling/disabling the various modes of operation. I am no expert on the assorted operational modes. That said, one mode is geared to setting up and configuring a new WiFi network on a new router. This is mode that gave the protocol its name: WiFi Protected Setup and it is not the operating mode with the security problem.
Three other operating modes allow a new WiFi client to logon to an existing WiFi network. They are illustrated in the screen shot below from a Linksys EA6200 router running firmware 220.127.116.11830.
One of the logon modes (shown on the left in the picture above) requires pushing buttons on both the router and the WiFi client. In this case the button is virtual but many WPS capable routers have a physical button, which the warning above references. Like a Bluetooth pairing, this type of WPS pairing is only active for a minute or so before it times out. I believe the official term for this mode of operation is Push Button Connect or PBC for short.
I suspect the Netgear Arlo Pro security camera uses the push button mode of WPS. The camera talks to a Netgear base station on a Wi-Fi network created by the base station. That Wi-Fi network supports WPS. The camera is linked to the base station by pushing buttons on the devices.
Push button mode does not have any remote security problems. Locally however, anyone that can touch a router with a physical WPS button, can get onto the Wi-Fi network.
Apple supports a mode of WPS they call "First attempt" for connecting WPS printers to the network. This uses the push-button method. It's not clear to me how Apple limits the functionality to just printers. I read the Setup Guide for an Apple router and the topic was not explained.
The mode of operation on the far right, which Linksys calls Device PIN, involves entering a serial number (a.k.a. PIN) associated with a WiFi device into the router. This mode too, does not have security problems as you first have to login to the router to use it. I have also seen this referred to as Client PIN mode. Apple AirPort routers use this to connect a WPS printer to the network.
There is also another mode of WPS operation, not shown above. It is the latest mode: NFC or Near Field Communication. If both the router and the wireless device support NFC then you can get on a wireless network just by touching the device to the router. If the router is offering multiple networks, such as a private 2.4GHz, a private 5GHz and a Guest, I have no idea which network the NFC device is assigned to.
I think there used to be yet another mode, that used a USB flash drive to transfer network configuration information.
The problematic mode, Router PIN, is in the middle box in the screen shot above. In this mode, when a new WiFi device wants to get on the network it can do so by providing the router with the hard coded WPS password (the technical term is "pin code") of the router. That set-in-stone WPS pin code is whats on the label on the bottom of every WPS capable router. In the screen shot above, we can see that the WPS PIN code for this router is 70307851.
The obvious problem with the Router PIN code mode of operation is that WiFi clients can guess, and guess and guess again, until they hit on the right code. At first it seems that 8 digits (the PIN codes are all numeric) should be enough to avoid mass guessing, but there is a HUGE design flaw that converts 100 million to 11 thousand.
An 8 digit number should mean that there are 100 million (zero through 99,999,999) possible codes. But no.
The last digit is a checksum, so we are down to 7.
The 7 digits however are not validated a single number. Instead, the WiFi device first offers the router 4 digits, gets that validated, then offers the last 3 digits for validation. Four digits is 10,000 possibilities. Three digits is 1,000. Adding them up yields the 11,000 mentioned above.
Anyone guessing would, on average, only need to make half the possible guesses before hitting pay-dirt. That gets us down to 5,500 guesses. It doesn't take computers very long to make 5,500 guesses.
Bottom line: anyone near a router that supports WPS can hack into it in a matter of hours. We may never know if the protocol was purposely designed this way to allow spying.
And, WPS is not just in routers. I have seen an Android v4.4 cellphone that had WPS turned on when it was used as a "Mobile Hotspot", sharing its 4G/LTE data connection via Wi-Fi. There was no way to disable this either. I have not tested Android 5, 6 or 7. Or, an iPhone either.
Software to make the 11,000 guesses is freely available in Kali Linux. It's called Reaver.
On top of this insecure design, we have also seen coding issues. While the WPS spec calls for routers to limit massive guessing of the PIN code, not all routers do so. In addition, back in December 2011 when the you-know-what first hit the fan about WPS, there were some routers that did not disable WPS, even after being told to do so.
More bugs have come to light in the years since. There have been at least four cases of bad coding that reduced the number of necessary guesses to well below 11,000. For details, see the reading list at the bottom of this page or the router bugs page. An April 2015 article by Paul Ducklin, We TOLD you not to use WPS on your Wi-Fi router! We TOLD you not to knit your own crypto! offers a good introduction to three different WPS programming flaws.
Want to check if your WiFi network supports WPS? As a rule, operating systems won't tell you. That is, the feature that scans for nearby networks and displays them, never identifies WPS. This is true for OS X, iOS, Windows, Android and Chrome OS. Apple, I believe, does not want iOS users to know. I know of no iOS apps that display the WPS status of a Wi-Fi network.
On Windows, the free and portable WifiInfoView by Nir Sofer displays a ton of technical information about detected Wi-Fi networks, including whether they support WPS or not. Mr. Sofer is an excellent source for Windows software.
If you know of other software that reports on WPS, please let me know.
Apple routers support WPS, but only partially.
For one thing, they seem to only support it for adding WPS enabled printers to the LAN. The AirPort Extreme Setup Gide says nothing about using WPS to connect anything other than a printer to the network. How the router can tell a printer from another type of wireless device is unclear to me. Since WPS is a standard published protocol, any type of device should be able to communicate using the protocol. In fact, someone said that in older versions of the AirPort utility, the feature was called 'Add Wireless Clients'.
In addition, Apple does not seem to support all the various WPS modes of operation. According to the AirPort Extreme setup guide, it supports a mode where you enter a number from the assumed printer into the router. This mode was never a security risk. It also supports another mode that Apple calls "First attempt" for, again, connecting a WPS printer to the network. The Setup Guide does not explain this mode at all. But, while Apple does not seem to update the Setup Guide, the do update their website. The document, Connect an AirPrint printer to a Wi-Fi network (last updated June 1, 2015) says "If you selected 'First attempt,' push the WPS button on the printer. When the printer's MAC Address appears in AirPort Utility, click Done." Outside of Apple, this is called the WPS push button method. It too, has never been a security issue.
What is Wi-Fi Protected Setup (WPS)? by Yasin Jabbar October 10, 2016. A Luma blog posting points out the security issue with WPS then says "Our Luma WiFi routers natively don't support WPS."
Frequently asked security questions by Eero. Quoting: "eero doesn't support WEP, WPA, or WPS, as these protocols are known to be insecure."
Google Wifi security features Quoting: "WPS, a mechanism that lets a device join a wireless network without entering a password, is also not supported for security reasons."
Getting started with the Ubiquiti AmpliFi mesh router by me November 2016. It does not do WPS.
Does Plume support WPS? Quoting: "Plume does not not support WPS as it was discovered to be a less secure procedure for establishing a WiFi network."
Does my Orbi WiFi System support Wi-Fi Protected Setup (WPS)? from Netgear. Article ID: 31239 Last Updated:03/29/2017. Quoting: "Yes. You can use the Sync button on your Orbi router and satellite to connect devices that support WPS." More details are available in the Orbi WiFi System User Manual (PDF) from March 2017. Reading page 23 (WiFi Connection Using WPS) makes it seem that Orbi only supports the push button method of WPS. While this is much more secure than the PIN method, it does still mean that anyone that can physically touch an Orbi can get on its network. The manual says nothing about whether this WPS feature can be disabled, so we have to assume it can not.
Linksys Velop User Guide (PDF). The manual has no date or release level which is always a bad sign. Page 17 describes how to "Connect a Device with WPS" and says "Wi-Fi Protected Setup allows you to easily connect wireless devices to your Wi-Fi without manually entering security settings." The screen shot of the mobile app shows it saying "WPS is a secure way for basic users to connect devices without complicated authentication details." Sane people disagree about WPS being secure. And, what the heck is a basic user? From the screen shot, it looks as if WPS can be disabled but the manual does not go into this at all. Perhaps most importantly, it is not at all clear which types of WPS are supported. At least Netgear was clear on this point.
The two sections above were written up by me in a blog posting on April 28, 2017: How seven mesh routers deal with WPS.
How to stop Wi-Fi hackers cold by Roger A. Grimes in InfoWorld May 26, 2015. The author helps out a neighbor whose router was being used by a bad guy to download illegal material thanks to WPS. Quoting: "Nearly every new feature intended to make computer security easier is bound to open up new vulnerabilities. Such is the case with WPS."
This April 2015 review of the $300 D-Link DIR 890L/R router at SmallNetBuilder.com points out that it does not let you disable WPS.
We TOLD you not to use WPS on your Wi-Fi router! We TOLD you not to knit your own crypto! by Paul Ducklin for Sophos April 2015. This describes two different bugs in programming WPS. Fairly technical. Sophos offers router software, the Sophos UTM that does not support WPS.
Reversing Belkin's WPS Pin Algorithm By Craig April 10, 2015. Exposing bad WPS programming by Belkin.
Reversing D-Link's WPS Pin Algorithm by Craig October 31, 2014. Exposing bad WPS programming by D-Link.
Using WPS on your Wi-Fi router may be even more dangerous than you think by Paul Ducklin for Sophos September 2, 2014 Describes the research by Dominique Bongard in the article below. The programming flaw he discovered converts a normally on-line WPS attack to off-line. Bad guys no longer need to make 11,000 guesses to the router. Off-line guessing attacks the WPS protocol itself and can yield the WPS pin code. There are bugs in at least two unspecified routers.
Offline bruteforce attack on WiFi Protected Setup by Dominique Bongard. Aug 6, 2014
Wi-FI Protected Setup (WPS) is Insecure: Here’s Why You Should Disable It by Chris Hoffman November 24th, 2013. Has an overview of the PIN and push-button connection methods. Ignores the other types of WPS.
Routers using WPS are intrinsically unsafe by Fred Langa in Windows Secrets newsletter Dec. 13, 2012. This explains four WPS methods of gaining network access, explains the security problem, offers advice on router configuration and verifying that WPS is really disabled. Not a great article, has some mistakes and omits the fact that Android network scanners can display the WPS status.
Putting Wi-Fi router's security to the test by Fred Langa Dec. 20, 2012. This is a follow-up article to the above that walks you through creating a BackTrack 5 Linux DVD, installing Reaver on it and setting it loose on a WPS enabled Wi-Fi router. A great way verify that WPS is really disabled and, as far as I know, the only way to tell if a router will stall or lock out an attacker after too many bad PIN guesses.
Waiting For The WPS Fix by Tim Higgins Jan. 7, 2012. Vendor responses right after the initial news.
Hands-on: hacking WiFi Protected Setup with Reaver by Sean Gallagher of Ars Technica Jan. 4, 2012. Ars being ars. Even with WPS supposedly disabled on a Linksys WRT54G2 Wireless-G Broadband Router, Gallagher was able to get it to cough up the SSID and password.
Researchers publish open-source tool for hacking WiFi Protected Setup by Sean Gallagher of Ars Technica Dec. 30, 2011. Quoting: "The routers most vulnerable to these attacks ... include products from Cisco's Linksys division, Belkin, Buffalo, Netgear, TP-Link, ZyXEL, and Technicolor. None of the vendors has issued a statement on the vulnerability, or replied to inquiries from Veihbock."
Brute forcing Wi-Fi Protected Setup When poor design meets poor implementation by Stefan Viehbock December 26, 2011. The original research that exposed the design flaw in WPS.
CERT Vulnerability Note VU#723755 WiFi Protected Setup (WPS) PIN brute force vulnerability. Dec 27, 2011. Big publicity at the start.
New Tools Bypass Wireless Router Security by Brian Krebs December 29, 2011. More publicity at the start.
Most Wi-Fi routers susceptible to hacking through security feature by Chester Wisniewski for Sophos December 30, 2011.
The Woops of WPS (Wi-Fi Protected Setup) raises its ugly head again by me April 2014. Basically, I am griping that articles about the new NFC flavor of WPS completely ignore the security problems with it.
Wi-Fi routers: Oldies are goodies by me January 2012. When I first learned of the WPS security problem, my router at the time did not support it because it was so old, it pre-dated WPS.
Wi-Fi_Protected_Setup at WikiPedia
Wi-Fi Protected Setup (WPS): The Easiest Way to Set Up Wireless Devices by Sharan Keswani July 12, 2011. A D-Link blog touting the WPS push button.