Are you using Sky Broadband in your home or business?  Are you still using the default wifi password?  Your business / home network is a potential target for hackers.

The algorithm used by Sky to generate wireless passwords is particularly weak against an offline dictionary attack which could allow intruders onto your network if the wireless key was cracked.

Sky Broadband use weak algorithm in their home / business routers. ( Model SR101)

We notified Sky Broadband about the problem in January 2014.  Sky Broadband are still supplying customers with modems / routers ( SR101 ) that use this weak algorithm to generate the wireless keys for each user.
At the time, graphics cards were expensive and clustering several machines was not financially viable to the average hacker.

In September 2014, we purchased a used rig, comprising off:

  • Windows 8 Pro
  • I5 Processor
  • 4GB RAM
  • 2TB Drive
  • Radeon HD 5850

For a tidy sum of: €245.00 :)

We generated 26 dictionary files using “mask processor” by ATOM, piping each letter out to its own file, for example:

  • A:  ./mp32 A?u?u?u?u?u?u?u > A.TXT = AAAAAAAA – AZZZZZZZ
  • B: ./mp32 B?u?u?u?u?u?u?u > B.TXT = BAAAAAAA – BZZZZZZZ
  • etc

Each .txt file weighed in at around 60GB’s each.  The 26 files took up about 1.6TB of storage.

We now had the complete key space, partitioned into 26 different files.  This allowed us to distribute the brute force attack amongst multiple computers.  There are other ways with ocl-hashcat but this was the simplest.

Using our Radeon HD5850 on standard settings, we were hitting 80,000 keys per second.  Breakdown below:

  • 26^8 = 208,827,064,576 ( 208 billion possible combinations )
  • 26^8 / 80,000 keys per second = 2,610,338 seconds
  • 2,610,338 / 60 seconds = 43,505 minutes
  • 43,505 / 60 minutes = 725 hours
  • 725 hours / 24 hours = 30 Days

For €245, we had built a computer that could crack the default Sky Broadband wireless password within 30 days.  The WPA-PSK handshake / password we tested started with the letter S and was cracked within 96 hours.

We ended up getting a second machine for the same price which resulted in our maximum cracking time being reduced to 15 days.

If you’re using the default wireless password on your Sky Broadband connection, we recommend changing it immediately to a more secure password, using a mix of letters, numbers and symbols.

If you have any queries or questions on the above, please feel free to leave a comment.