Re: Cisco VPN password recovery program

[Bill Squier]

On Oct 19, 2005, at 10:29 AM, Perry E. Metzger wrote:



Via cryptome:

http://evilscientists.de/blog/?page_id=343

   The Cisco VPN Client uses weak encryption to store user and group
   passwords in your local profile file.  I coded a little tool to
   reveal the saved passwords from a given profile file.

If this is true, it doesn't sound like Cisco used a particularly smart
design for this.


No matter what their strategy for encrypting the on-disk passphrase,  
this simple trick will work:


"ltrace -i ./vpnclient connect ... 2>&1 | fgrep 805ac57" (or similar  
library call tracing technique on an OS besides linux).


This used to be used by

http://www.unix-ag.uni-kl.de/~massar/bin/cisco-decode

but apparently they've switched to the evilscientists' method.

-wps


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Re: Cisco VPN password recovery program

[Florian Weimer]

> http://www.cisco.com/en/US/products/hw/vpndevc/ps2284/products_configuration_guide_chapter09186a00803ee1f0.html#wp2477015
>
> - - -
>
> Cisco Client Parameters
>
> Allow Password Storage on Client - Check this box to allow IPSec
> clients to store their login passwords on their local client
> systems. If you do not allow password storage (the default), IPSec
> users must enter their password each time they seek access to the
> VPN. For maximum security, we recommend that you not allow password
> storage.
>
> - - -

I really doubt that this affects group password (PSK).

In some cases, network administrators used the password obfuscation to
force their users to use Cisco's VPN client.  Competing products, such
as vpnc, do not enforce client-side policies.  However, there's been a
website where you can upload the obfuscated password, and it returns
the password in clear text for quite some time now.  It is implemented
by running the Cisco client under a debugging tool, intercepting a
memcpy call that copies the password.

In the end, the publication of the algorithm doesn't change the
security of the system (there wasn't much to start with).  But it's
certainly easier to write interoperable software using this
information.

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Re: Cisco VPN password recovery program

[Florian Weimer]

* Perry E. Metzger:

> Via cryptome:
>
> http://evilscientists.de/blog/?page_id=343
>
>The Cisco VPN Client uses weak encryption to store user and group
>passwords in your local profile file.  I coded a little tool to
>reveal the saved passwords from a given profile file.
>
> If this is true, it doesn't sound like Cisco used a particularly smart
> design for this.

Why?  In essence, this is the PSK that is used to authenticate the VPN
gateway.  It must be available in cleartext on the client.

(Later versions offer asymmetric encryption as well.)

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Re: Cisco VPN password recovery program

[Andrea Pasquinucci]

On Wed, Oct 19, 2005 at 10:29:19AM -0400, Perry E. Metzger wrote:
* 
* Via cryptome:
* 
* http://evilscientists.de/blog/?page_id=343
* 
*The Cisco VPN Client uses weak encryption to store user and group
*passwords in your local profile file.  I coded a little tool to
*reveal the saved passwords from a given profile file.
* 
* If this is true, it doesn't sound like Cisco used a particularly smart
* design for this.
* 

Only for information, here is Cisco reply as passed on 
full-disclosure@lists.grok.org.uk and bugtraq@securityfocus.com

Andrea


From: Clayton Kossmeyer <[EMAIL PROTECTED]>
Subject: Re: [Full-disclosure] Ciscos VPN-Client-Passwords can be decrypted
Date: Tue, 18 Oct 2005 16:06:05 -0400
To: full-disclosure@lists.grok.org.uk
Cc: bugtraq@securityfocus.com, [EMAIL PROTECTED]


Hello -

The Cisco PSIRT is aware of reports that claim the Cisco VPN Client
password encryption uses a breakable algorithm to encrypt user
passwords.

We are aware of reports at the following sites:

   http://www.heise.de/newsticker/meldung/64954
   http://evilscientists.de/blog/?page_id=339
   http://evilscientists.de/blog/?page_id=343

This issue is related to a Security Notice that the Cisco PSIRT
released in October of 2004.  Cisco's public announcement can be found
here:

http://www.cisco.com/warp/public/707/cisco-sn-20040415-grppass.shtml

The Cisco VPN 3000 Series has a configuration option that does not
allow the storage of the user password in the VPN client. For
customers that are concerned about the recovery of the user password,
the following option can be disabled to prevent local storage of the
user password.

http://www.cisco.com/en/US/products/hw/vpndevc/ps2284/products_configuration_guide_chapter09186a00803ee1f0.html#wp2477015

- - -

Cisco Client Parameters

Allow Password Storage on Client - Check this box to allow IPSec
clients to store their login passwords on their local client
systems. If you do not allow password storage (the default), IPSec
users must enter their password each time they seek access to the
VPN. For maximum security, we recommend that you not allow password
storage.

- - -

Note that the default configuration of the VPN 3000 Series does not
allow client password storage. Additionally, this attack only affects
passwords that are static and reused for login to the VPN
network. Customers using one-time passwords (OTP) and certificates to
connect are unaffected.

We do greatly appreciate the opportunity to work with researchers on
security vulnerabilities, and welcome the opportunity to review and
assist in product reports.

Regards,

Clay
Cisco PSIRT



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Re: Cisco VPN password recovery program

[Eugen Leitl]

On Wed, Oct 19, 2005 at 09:45:38AM -0500, Alaric Dailey wrote:

> Cisco seems to be doing these kinds of boneheaded things for quite sometime.

Does Juniper have a better security story?

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Re: Cisco VPN password recovery program

[Alaric Dailey]

Perry E. Metzger wrote:

Via cryptome:

http://evilscientists.de/blog/?page_id=343

   The Cisco VPN Client uses weak encryption to store user and group
   passwords in your local profile file.  I coded a little tool to
   reveal the saved passwords from a given profile file.

If this is true, it doesn't sound like Cisco used a particularly smart
design for this.

  
Yeah, and they use simple character replacement for storing the admin 
password on their DSL modems, specifically the 675 and 678 models, they 
use telnet to admin the things and finally Their idea of how to 
protect these modems from the CodeRED worm is to change the port the web 
interface is listening on.


Cisco seems to be doing these kinds of boneheaded things for quite sometime.

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Cisco VPN password recovery program

[Perry E. Metzger]

Via cryptome:

http://evilscientists.de/blog/?page_id=343

   The Cisco VPN Client uses weak encryption to store user and group
   passwords in your local profile file.  I coded a little tool to
   reveal the saved passwords from a given profile file.

If this is true, it doesn't sound like Cisco used a particularly smart
design for this.

-- 
Perry E. Metzger[EMAIL PROTECTED]

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