ALERT: WPA isn't necessarily secure

SUMMARY:

WPA-PSK is vulnerable to offline attack.

TO AVOID THE PROBLEM:

USE A PASSPHRASE WITH MORE THAN 20 CHARACTERS. Examples: BAD: "vintage wine" GOOD: "floor hiking dirt ocean" (pick your own words, even longer is better) FOR HIGH SECURITY, USE MORE THAN 32 CHARACTERS.

BACKGROUND:

Weakness in Passphrase Choice in WPA Interface By Glenn Fleishman By Robert Moskowitz Senior Technical Director ICSA Labs, a division of TruSecure Corp

... The offline PSK dictionary attack ... Just about any 8-character string a user may select will be in the dictionary. As the standard states, passphrases longer than 20 characters are needed to start deterring attacks. This is considerably longer than most people will be willing to use.

This offline attack should be easier to execute than the WEP attacks. ... Using Random values for the PSK

The PSK MAY be a 256-bit (64 hexadecimal) random number. This is a large number for human entry; 20 character passphrases are considered too long for entry. Given the nature of the attack against the 4-Way Handshake, a PSK with only 128 bits of security is really sufficient, and in fact against current brute-strength attacks, 96 bits SHOULD be adequate. This is still larger than a large passphrase ... ... Summary ... Pre-Shared Keying is provided in the standard to simplify deployments in small, low risk, networks. The risk of using PSKs against internal attacks is almost as bad as WEP. The risk of using passphrase based PSKs against external attacks is greater than using WEP. Thus the only value PSK has is if only truly random keys are used, or for deploy testing of basic WPA or 802.11i functions. PSK should ONLY be used if this is fully understood by the deployers.

See also: Passphrase Flaw Exposed in WPA Wireless Security

Wi-Fi Protected Access. Security in pre-shared key mode

Cracking Wi-Fi Protected Access (WPA)

WPA Cracker

Reply to
John Navas
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All those words are included in a pretty simple english dictionary with less than 1000 words, which means a password phrase with four of those words will give 1 000 ^ 4 combinations. With my crack algorythm and a puter it would take me less than 10 days to find the phrase. With a simple asic, less than three minutes.

For the password phrase not to be weaker than AES itself, you need 13 random words from a simple dictionary with at least 1000 words. For random letters (a-z) the number is 28. This means "threre is nothing I like more than a good disbute with my friends on a daily basis every day" is about as secure as "wdhozjlktiolbhdkeorjmfdhierk". Remember not to count for the short words in the phrase.

Reply to
Chrisjoy

On Mon, 15 Dec 2008 15:09:45 -0800 (PST), Chrisjoy wrote in :

Correct. That's the idea.

That's sufficient for most people, but I go on to say: FOR HIGH SECURITY, USE MORE THAN 32 CHARACTERS Those numbers?

That's not a meaningful criteria.

Reply to
John Navas

Who are you to tell what is sufficient, crackpot?

Already told you. 28 (a-z) (excluding A-Z)

With 32 you got a stronger password than the cryption behind, which is meaningless.

That's the ONLY meaningful criteria.

Reply to
Chrisjoy

On Mon, 15 Dec 2008 17:19:38 -0800 (PST), Chrisjoy wrote in :

With that insult you concede the debate. Thanks for saving me the time.

Reply to
John Navas

I didn't think you would be able to produce a reasonable answer to my valid objection, dumb f*ck.

Reply to
Chrisjoy

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