RE: Serious flaw in Linksys wireless AP password security

From: Robert Thompson Jr. (rthompson_at_columbiabank.com)
Date: 08/16/05

  • Next message: Boren, Rich (HP SSRT): "[security bulletin] SSRT4874 rev.0 - HP-UX Ignite-UX Remote Unauthorized Access" 
    Date: Tue, 16 Aug 2005 11:59:15 -0700
To: "Steve Scherf" <steve@moonsoft.com>, <bugtraq@securityfocus.com>

    Thank you for the link. I appreciate it.

    After reading through it, I am beginning to see where I may have
    misunderstood what you were getting at.

    When I was attempting to get into the router, with WZC set open, and
    encryption was enabled on my router, but not on my nic, there was no
    connecting.

    And with a wrong key, no connecting.

    BUT - one thing that I did not do, was attempt to connect to the router
    via WZC with the encryption turned ON but with no key supplied. I
    always had a key loaded should the encryption be enabled.

    I will test encryption on with no key when I get home tonight and see
    what happens. Unfortunately, I will have to flash back down to the
    4.50.6 firmware, BUT I'm curious.

    Again, thank you for the link...

    -----Original Message-----
    From: Steve Scherf [mailto:steve@moonsoft.com]
    Sent: Tuesday, August 16, 2005 11:00 AM
    To: Robert Thompson Jr.
    Cc: Steve Scherf; bugtraq@securityfocus.com
    Subject: Re: Serious flaw in Linksys wireless AP password security

    FYI, the problem I reported has been reproduced over at Broadband
    Reports:

    http://www.broadbandreports.com/forum/remark,14141344 

    --
Steve Scherf
steve@moonsoft.com
On Mon, Aug 15, 2005 at 03:42:03PM -0700, Robert Thompson Jr. wrote:
> From: "Robert Thompson Jr." <rthompson@columbiabank.com>
> Subject: RE: Serious flaw in Linksys wireless AP password security
> Date: Mon, 15 Aug 2005 15:42:03 -0700
> To: Steve Scherf <bugtraq@moonsoft.com>, bugtraq@securityfocus.com
> 
> When upgrading my WRT54GS (v 1.0) router to the 4.50.6 and 4.70.6 
> firmwares, I experienced no such authentication problems.
> 
> If the router was set wide open, I could connect without
authentication.
> 
> As soon as I specified WPA-PSK on the router, in order for me to 
> connect via the NIC I absolutely had to have the WZC configured for 
> WPA-PSK (TKIP or AES accordingly) and HAD to have the correct password
> configured as well.  (And the SSID of course...)
> 
> If the proper settings were not configured into the WZC after enabling
> WPA-PSK, I was not able to connect to the router.
> 
> I am certain of these details as I was trying to get the WPA2 feature 
> to work on my NIC that didn't have WPA2 certified drivers at the time.
> I ended up trying every damned near possible configuration before 
> realizing that it was my drivers that weren't working on my NIC before
> having to settle with just WPA until Linksys updated their drivers on 
> their website...
> 
> Though, since we are on the subject of the WRT54GS router.  The 4.50.6
> and 4.70.6 firmwares enable the WPA2 feature.  AND Linksys was kind 
> enough to finally release WPA2 certified drivers for the WPC54GS NIC's
> (and I am assuming the WPC54G) as well.  So if you haven't updated, 
> you may want to condsider doing so for the increased security.
> 
> Rob.
> 
> 
> 
> -----Original Message-----
> From: Steve Scherf [mailto:bugtraq@moonsoft.com]=20
> Sent: Sunday, August 14, 2005 12:53 AM
> To: bugtraq@securityfocus.com
> Subject: Serious flaw in Linksys wireless AP password security
> 
> It appears that firmware version 4.50.6 for the Linksys WRT54GS 
> (hardware version 1) wireless router allows wireless clients to 
> connect and use the network without actually authenticating. With WPA 
> Personal/TKIP authentication enabled, the unit allows both clients 
> using encryption with the correct settings and key, and clients not 
> using any encryption. It disallows clients attempting to use 
> encryption with the wrong settings and/or key.
> 
> In other words, even if you think you've secured your wireless network
> from unauthorized access, anyone can access it. It actually shows up 
> as having no password security on a Macstumbler scan, which is how I 
> noticed the problem.
> I verified that anyone can access the network without needing to know 
> the key.
> 
> I did not check security modes other than WPA/TKIP. Other modes may 
> have different behavior. Changing the "Authentication Type" setting 
> had no effect on this problem. I believe it should be set to "Shared 
> Key", but the setting used does not appear to matter.
> 
> I only verified the problem on firmware 4.50.6. It is unknown if other
> firmware versions exhibit the problem. However, at least one older 
> firmware does not exhibit the problem, as my router functioned 
> correctly until I updated to 4.50.6.
> 
> The problem appears to be fixed in version 4.70.6. No expli*** notice
> of this problem or the fix appears in the release notes for version 
> 4.70.6.
> Strangely, the "Authentication Type" must be set to "Auto" for the 
> unit to function properly. Should it be set to "Shared Key", which one
> might expect to be the correct value, the wireless functionality 
> appears to be entirely disabled.
> 
> It is unknown if this problem is seen with other hardware versions, or
> with other models. I suspect it may, given the similarity between many
> of the Linksys models and their firmware.
> 
> 
> --
> Steve Scherf
> bugtraq@moonsoft.com
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