Feeds

Wi-Fi Protected Setup easily unlocked by security flaw

Couple of hours of brute force will crack a network's PIN

Providing a secure and efficient Helpdesk

Security researcher Stefan Viehböck has demonstrated a critical flaw in the Wi-Fi Protected standard that opens up routers to attack and has prompted a US-CERT Vulnerability notice.

Wi-Fi Protected Setup (WPS) is used to secure access to wireless networks and requires each router to have a unique eight-digit PIN. One mode of use allows a device to connect by just presenting that PIN, opening the way for a client to just try every available PIN. Worse still, the protocol splits the PIN into two halves which reduces the attack time to a couple of hours.

Eight digits should produce 100,000,000 possible combinations, and testing various routers Viehböck found it took an average of around two seconds to test each combination. So brute forcing should take several years unless the router was particularly responsive.

But the protocol used by Wi-Fi Protected Setup reports back after the first four digits have been entered, and indicates if they are right, which means they can be attacked separately. The last of the eight digits is just a checksum, so having got the first four the attacker only then has to try another 1,000 combinations (identifying the other three digits) and the entire PIN is known.

That combination means that our attacker only has to try 11,000 different combinations to find the right PIN, reducing the attack time to a couple of hours.

In documented tests (PDF, surprisingly understandable) Viehböck found that of all the routers he tried only the one from Netgear had any sensible response to being repeatedly presented with incorrect PINs, slowing its responses to mitigate against the attack, but with only 11,000 combinations to try that only extended the attack time to a day or so.

Most services will start to slow up when incorrect credentials are presented repeatedly, but it seems router manufacturers have relied on the huge number of possible PINs to keep them safe. Hopefully that means a simple software fix, but until then the US-Cert is recommending that WPS be switched off, and going back to the MAC Address white list. ®

New hybrid storage solutions

More from The Register

next story
Apple Pay is a tidy payday for Apple with 0.15% cut, sources say
Cupertino slurps 15 cents from every $100 purchase
Google recommends pronounceable passwords
Super Chrome goes into battle with Mr Mxyzptlk
Reddit wipes clean leaked celeb nudie pics, tells users to zip it
Now we've had all THAT TRAFFIC, we 'deplore' this theft
YouTube, Amazon and Yahoo! caught in malvertising mess
Cisco says 'Kyle and Stan' attack is spreading through compromised ad networks
TorrentLocker unpicked: Crypto coding shocker defeats extortionists
Lousy XOR opens door into which victims can shove a foot
Greater dev access to iOS 8 will put us AT RISK from HACKERS
Knocking holes in Apple's walled garden could backfire, says securo-chap
Microsoft to patch ASP.NET mess even if you don't
We know what's good for you, because we made the mess says Redmond
NORKS ban Wi-Fi and satellite internet at embassies
Crackdown on tardy diplomatic sysadmins providing accidental unfiltered internet access
prev story

Whitepapers

Providing a secure and efficient Helpdesk
A single remote control platform for user support is be key to providing an efficient helpdesk. Retain full control over the way in which screen and keystroke data is transmitted.
Top 5 reasons to deploy VMware with Tegile
Data demand and the rise of virtualization is challenging IT teams to deliver storage performance, scalability and capacity that can keep up, while maximizing efficiency.
Reg Reader Research: SaaS based Email and Office Productivity Tools
Read this Reg reader report which provides advice and guidance for SMBs towards the use of SaaS based email and Office productivity tools.
Security for virtualized datacentres
Legacy security solutions are inefficient due to the architectural differences between physical and virtual environments.
Secure remote control for conventional and virtual desktops
Balancing user privacy and privileged access, in accordance with compliance frameworks and legislation. Evaluating any potential remote control choice.