Steve Smith explains the difference between WEP, and WPA wireless security. Also, goes indepth into AES, TKIP, RC4, symmetric key algorithms, and their weaknesses.
Episode #3-06 released on October 21, 2012
Network security is of great importance, especially when you wish to prevent unauthorized access of your network to those that would drain your resources, and pirate digital media in your name.
Unauthorized users can also scan the traffic, sniff the data passing by, implant viruses in unprotected shared folders, etc... For those with bandwidth caps, you can end up paying a premium for all those extra downloads you didn't do, and when someone does pirate your material, it may be extremely difficult to determine who is the perpetrator of the crime. Theft is theft, and like your front door, you need to make sure you have the best protection in place to prevent intruders from entering in your network. This is mostly an issue for wireless networks, and its the reason of the episode.
It is known that we currently have two general options for network security, WEP and WPA. Some people are convinced that WEP is more secure than WPA, and I will be explaining why that is in fact false.
WEP, also known as Wired Equivalent Privacy, introduced in September 1999, was created to provide the same security as the more commonly used wired networking of the time. You can identity WEP by its 10 or 26 character hexadecimal pin, and it is the mostly commonly indicated first choice on most wireless routers. WEP uses RC4 cryptography in order to secure data.
RC4, is a cryptographic stream cipher, sometimes known as ARC4, or ARCFOUR, and is the most widely used software based stream cipher, and is also used in such protocols as SSL, WEP, and has a severe weakness based in a vulnerability related to the beginning of the output keystream, if it is not discarded. Incorrect or weak implementations of RC4 leads to weak security methods, such as WEP.
WPA, also known as Wi-Fi Protected Access, was released in 2003, was created as a temporary solution awaiting WPA2, due to the many security issues that came arise from the use of WEP.
Two forms of security were used in WPA as a result of the weakness presented in WEP. TKIP, or Temporal Key Integrity Protocol, and AES, or Advanced Encryption Standard.
So, want to know what was wrong with the WEP implementation of security? WEP used RC4, a stream cipher, that meant that the traffic key had to never be used twice in order to avoid security issues. However, this stream cipher was only 24-bits long, and meant that you had a 50% chance of repetition every time you have more than 5000 packets, really easy to accomplish on busy networks.
It was, also, possible to eaves drop from over a mile away with proper equipment on WEP protected wireless systems. WEP, was, also, optional. Being an optional technology means novices and the misinformed will not use it unless someone they know installs it, or they willingly take the time to use it themselves.
TKIP, Temporal Key Integrity Protocol, was designed to replace WEP/RC4 wireless security system as a temporary solution awaiting the new AES standard to be added into WPA2. It was capable of being added to legacy network cards because it did not leave the hardware without a viable link-layer security. However, it was impossible to update the firmware of routers created before 2003 because of the many hardware issues that would arise.
AES, Advanced Encryption Standard, was also named Rijndael, and is a cipher created by two Belgium Cryptographers, Joan Daemen, and Vincent Rijmen, who submitted it to the AES selection process. AES superseeds the previous DES, or Data Encryption Standard created in 1977, and is now the most widely used symmetric-key algorithm, meaning it uses the same key to encode and decode traffic.
Knowing this, in order to maximize the security of your wireless network, whichever is it, WEP or WPA. The answer is neither, you better off using WPA2 with AES as the stream cipher, and a really strong password, as well, as turning off WPS whenever possible to maximize security. However, an implementation of WPA with AES does exist, and can be used whenever network cards are unable to use the WPA2 standard of wireless security.
Now, some may be inclined to state that using WEP is better than using nothing, but the disturbing fact is, that with our newer computers and graphics card capable of processing insane amounts of data at a time, it takes less than 60 seconds for anyone to break into a WEP enabled secure wireless network, meaning using WEP is equal to using nothing to protect your wireless network.
One possible attack vector with an ends to identify theft may include the sniffing of traffic long range on networks using WEP, then forcing the victim to have their passwords reset and intercepting the password reset emails which are rarely acquired by secure means. This allows the perpetrator the ability to not only change the password by access that account, and possibly any connected to this account it the case of Facebook, Google, or even Twitter, and more. This attack method can be done at a mile distance with the right equipment. The time required to crack WEP is less than 60 seconds, so this attack pattern could be done in extremely short duration.
The only viable local attack vector against WPA and WPA2 is through the WPS weakness, which limits the distance to several dozen feet, not a mile. And this would allow the perpetrator to access the network but the time required is can be as long as 46 hours or more, and requires to be within range of the network. The use of firmware such as Tomato on compatible routers renders that attack method unusable. However, once on the network, the perpetrator can sniff the traffic, request a password reset, intercept the password e-mail, and take hold of your accounts.
These attacks could be used to steal financial information, emails, etc... Using strong passwords, and even stronger cryptography, as well as turning off WPS, UPNP and remote access to your router, as well as changing default passwords of all equipment are the only ways to slow down these kinds of attacks.
Next week, I'll take you on a guided tour through the new Ubuntu 12.10 operating system, and many of its new features and tools.
And, if anything in this episode interests you, and you want a more in depth introduction to any of the encryption technology, techniques like symmetric encryption, stream ciphers, block ciphers, etc... just comment you interest below on Youtube, on the shows notes page at http://tqaweekly.com/se3ep06, or e-mail me at ask@tqaweekly.com.
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Host : Steve Smith | Music : Jonny Lee Hart | Editor : Steve Smith | Producer : Zed Axis Productions