Re: Inexcusable weakness in Kmail / GnuPG

From: Simple Nomad (thegnome_at_nmrc.org)
Date: 12/24/04

  • Next message: Donato Ferrante: "XSS in yacy 0.31" 
    To: "Thomas C. Greene" <thomas.greene@theregister.co.uk>
Date: Fri, 24 Dec 2004 00:30:24 -0600

    <snip>

    > So i compose my reply, and i'm just about to click the Send button, when i
    > notice, quite by chance, that the reply is *not* encrypted by default, and i
    > am not warned about this fact. My reply, and my entire past exchange with
    > the source, is about to go out in fscking clear text!

    Most if not all mailers are affected by certain bugs related to this. It
    "forgets" the passphrase, but does it free the variable? Does it wipe
    the variable with 0's or random data as soon as it is done with the
    passphrase, assuming it is supposed to forget it? Does it page to swap?
    Can this be prevented by running as root, which can do an mlockall()? Is
    the binary suid root to allow non-root users to mlockall()? Are
    privileges dropped? Is running suid root the best way to solve this
    problem? Is a temp file used to create the encrypted message? Is the
    temp file securely wiped? Where is the temp file written? Can simply
    encrypting/decrypting by hand and importing/exporting/cutting/pasting
    into the mail program an easier way to solve this for paranoid users?

    Most mailers fail one or more of these tests. If this hasn't been
    discussed, it should be, but it should also be discussed in the context
    of whether the system running GPG is secure or not, and how hard would
    it be to exploit the bugs. If someone can access your swap, you have all
    kinds of problems, not just the possible passphrase recovery from the
    swap itself.

    As far as the functional bugs as stated below in mailers, I'm sure there
    are others as I have seen this type of bug before -- where you are
    allowed to sent email unencrypted when you think it is encrypted --
    although for the life of me I cannot remember the mail program. IIRC I
    did report the error to the mailer's authors, but switched mailers. I
    recommend either contacting the authors, writing a patch, or switching
    mail programs. 

    -- 
- Simple Nomad ---- thegnome@nmrc.org ---- thegnome@razor.bindview.com -
- "Patriotism means to stand by the country. It does not mean to stand -
- by the President or any other public official." - Theodore Roosevelt -

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