Other responses should be off list, directly to me.
Pat
-----BEGIN PGP SIGNED MESSAGE-----
I have been asked by Steve Crocker, CyberCash's Chief Technical Officer,
to post this message concerning security of CyberCash's software.
The following should appear in its entirety if it's printed at all.
Permission is granted to repost this message as long as the entire
message is reposted unaltered with the PGP signature intact.
Pat
The following message appeared on the net.
> === begin quoted message ===
>
>From: Anonymous <anon@ANON.EFGA.ORG>
>Subject: Major security flaw in Cybercash 2.1.2
>To: BUGTRAQ@NETSPACE.ORG
>
>CyberCash v. 2.1.2 has a major security flaw that causes all credit
>card information processed by the server to be logged in a file with
>world-readable permissions. This security flaw exists in the default
>CyberCash installation and configuration.
>
>The flaw is a result of not being able to turn off debugging. Setting
>the "DEBUG" flag to "0" in the configuration files simply has no
>effect on the operation of the server.
>
>In CyberCash's server, when the "DEBUG" flag is on, the contents of
>all credit card transactions are written to a log file (named
>"Debug.log" by default).
>
>The easiest workaround I've found is to simply delete the existing
>Debug.log file. In my experience with the Solaris release, the
>CyberCash software does not create this file at start time when the
>DEBUG flag is set to 0.
>
>The inability to turn off debugging is noted on CyberCash's web site
>under "Known Limitations". The fact that credit card numbers are
>stored in the clear, in a world readable file, is not.
>
> === end quoted message ===
We have taken this quite seriously and have put through a full release
of our software which will be available Monday 11/24 for three
platforms and others shortly thereafter. The flaw was in the
debug logging function, not in the protocols or core
implementation. Nonetheless, the effect was an unnecessary
exposure of potentially sensitive information, and it shouldn't
have gone out the door that way. We're tightening our internal
processes to avoid this in the future.
That said, here's the actual exposure. The credit card information
that's in the clear in the log comes from "merchant-initiated"
transactions, which means the merchant obtains the credit
card number from somewhere -- phone, mail, fax, SSL-protected
Internet interaction, or unprotected Internet interaction.
The merchant thus has the same info in the clear already.
If the card number was provided via a wallet, then the card
number is blinded at the consumer's end. It is therefore
not in the clear as it passes through the merchant's machine
and the reported exposure does not apply..
In order for the unprotected log to pose a risk of exposure,
someone has to be able to gain access to the merchant's machine.
If the machine is well protected, viz behind a firewall and/or
carefully configured, presumably an outsider won't be able to
gain access. And in terms of the *additional* exposure the
open log represents over existing risks, if the same information
is accessible in the clear elsewhere on the machine, eliminating
from the log or encrypting the log provides little or no real
protection. We continue to advise merchants to take strong steps
to protect their machines.
To our knowledge, the exposure documented above has not resulted
in the actual loss of any customer data or other security incident.
- ----------------------------------
Steve Crocker Desk: +1 703 716 5214
CyberCash, Inc. Main: +1 703 620 4200
2100 Reston Parkway Fax: +1 703 620 4215
Reston, VA 20191 crocker@cybercash.com
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Pat Farrell CyberCash, Inc. w:(703) 715-7834
Senior Engineer pfarrell@cybercash.com
#include standard.disclaimer