best practices to secure home's network

[Neill Massello]

Enough already! I read it the first time...

One more time Navas, one more time, and pow! right in the killfile.

 

[Jeff Liebermann]

Assuming that an attacker does guess the WPA passphrase, however long or
random it is, what does that get him? Will he then be able to decrypt
all traffic to and from all clients on the wireless network?

Yes. With WPA-PSK, the pass phrase is the decryption key. If the
attacker can recover the WPA-PSK phrase, he can:
1. Impersonate an existing user.
2. Sniff all traffic and recover embarrassing documents and plain
text passwords from other users.
3. Run the recovered WPA key on the capture log and recover the
contents in unencrypted form.
4. Inject spoofed or counterfeit traffic.
5. Instigate denial of service attacks.
6. Bypass all the firewall rules (because he's on the LAN side of the
firewall).
7. Provide business for network security consultants.

Note that with WPA-TKIP and WPA-RADIUS, the WPA encryption key is
unique by the connection. There is no system wide common pass phrase.
Therefore, the attacker would need to recover each key for each user
individually. Since this is a temporary key that is rather long,
changes often, and changes with each session, chances of recovering
this key are minimal. Even if the key were recovered, it would not be
useable for the aformented exploits.

You should read the references supplied by John Navas. There's quite
a bit in there on how it all works and what can go wrong, go wrong...

 

[Derek Broughton]

Step two: do you _really_ need wireless?

Well, yeah! I'm really getting quite hooked on using my laptop anywhere I
feel like it.

 

[John Navas]

[POSTED TO alt.internet.wireless - REPLY ON USENET PLEASE]

In <[email protected]> on Tue, 11 Oct 2005 21:20:12

The end of wireless as we know it is at hand. Repent your evil ways
and prepare for the coming of yet another deluge of acronyms. Though
thou sacrifice upon the altar of fallen standards, thy petition for
data safety is in vain, for the priests only deliver complexity, and
little safety. Best to await the coming of the messiah, who shall
lead the multitudes to a land of perfect cryptography, infinite
bandwidth, readable standards, and omniscient tech support. Meanwhile,
learn, read, and suffer your way towards enlightenment.

If you're going to use my favorite method of spreading FUD (fear,
uncertainty, and doubt), then at least offer the recommended solution
to the WPA security problems. I wouldn't want to see another internet
rumor start here.

I did that in the part you snipped.

If the user selects a WPA pre-shared key that's longer than 20
characters (63 chars maximum) and is not found in a typical word list
dictionary, then WPA-PSK is fairly safe from dictionary attack.

I agree. The longer the better.

The WPA security problems also only apply to WPA-PSK and do not apply
to WPA-RADIUS, WPA-TKIP, and WPA-2.

True, as the material you snipped makes clear.

If you're going to accuse me of starting Internet rumors, at least have the
courtesy not to snip relevant materials from my post.

 

[John Navas]

[POSTED TO alt.internet.wireless - REPLY ON USENET PLEASE]

One more time Navas, one more time, and pow! right in the killfile.

Knock yourself out.

 

[Jeff Liebermann]

If you're going to accuse me of starting Internet rumors, at least have the
courtesy not to snip relevant materials from my post.

Guilty as charged. I'll put it back.

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.
(...)
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 ...

The way I read this is that the WPA-PSK pass phrase should be longer
than 20 characters but such pass phases are designated by the author
as "too long for entry" and "longer than most people will be willing
to use".

With all due respect, this is not exactly what I would call a clear
suggestion that over 20 characters is adequate WPA-PSK security and
may be safely used. It also makes no mention that only WPA-PSK is
vulnerable to such attacks and that other forms of WPA are acceptable.
Methinks it would have been better if you clearly specified the
limitations and alternatives to WPA-PSK. It's not like this is
something totally new as the problem was first identified in Nov 2003.


--
Jeff Liebermann 150 Felker St #D Santa Cruz CA 95060
831.336.2558 voice
http://www.LearnByDestroying.com AE6KS
http://802.11junk.com Skype: JeffLiebermann
(e-mail address removed)-cruz.ca.us (e-mail address removed)

 

[Neill Massello]

You should read the references supplied by John Navas.

The answer to my question was in the WiFi Net News article
<http://wifinetnews.com/archives/002452.html>:

"Thus even though each unicast pairing in the ESS has unique keys (PTK)
there is nothing private about these keys to any other device in the
ESS."

"Anyone with knowledge of the PSK can determine any PTK in the ESS
through passive sniffing of the wireless network, listening for those
all-important key exchange data frames."

 

[enrique]

You can use OpenVPN (available for Windows, Linux, Mac, Solaris, ... )
as logical AP, leaving WiFi just the low link layer connection.
OpenVPN offers much more secure protection than conventional WiFi ones
(WEP, WPA,...) - even Public Key Criptography if needed. -