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Groups > linux.debian.security > #5510

Re: RFC: proposed fix for CVE-2018-19518 in uw-imap

From Tomas Bortoli <tomasbortoli@hotmail.it>
Newsgroups linux.debian.security
Subject Re: RFC: proposed fix for CVE-2018-19518 in uw-imap
Date 2018-12-26 09:50 +0100
Message-ID <x9d33-qg-5@gated-at.bofh.it> (permalink)
References <x82CJ-7hv-1@gated-at.bofh.it> <x8GgO-61K-7@gated-at.bofh.it> <x8GgO-61K-5@gated-at.bofh.it>
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Hi Roberto,

On 12/24/18 10:40 PM, Roberto C. Sánchez wrote:
> There are two command templates involved in this section of code:
> rshcommand and sshcommand.  The two for loops each operate on a
> different command template.

Ah ahn.. I missed that single byte difference, thanks.

> Yes, the description could certainly use more detail.  That said, I did
> include this in my original post:
>
>     I also wondered whether it was possible to cause the vulnerability
>     without a space in the hostname (somewhat related to the first
>     question).  In any event, I concluded that the question of whether
>     something is a valid hostname might be a bit complex to tackle and
>     despite numerous attempts I was not able to exploit the
>     vulnerability without the space between the host name and the
>     command switch '-'.
>
> I suppose it would be possible to apply the approach of counting tokens
> to the host variable to ensure that it only contains a single token.
> However, I do not think that is any better or worse than the approach I
> came up with.
>

What about "shell escaping" the host name? Not sure about escaping the
other parameters too..but that shouldn't harm.
It should be the best security practice against command injection, AFAIK.


Happy Christmas,
Tomas



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Thread

RFC: proposed fix for CVE-2018-19518 in uw-imap Roberto C. Sánchez <roberto@debian.org> - 2018-12-23 04:30 +0100
  Re: RFC: proposed fix for CVE-2018-19518 in uw-imap Roberto C. Sánchez <roberto@debian.org> - 2018-12-24 22:50 +0100
    Re: RFC: proposed fix for CVE-2018-19518 in uw-imap Tomas Bortoli <tomasbortoli@hotmail.it> - 2018-12-26 09:50 +0100
  Re: RFC: proposed fix for CVE-2018-19518 in uw-imap Tomas Bortoli <tomasbortoli@hotmail.it> - 2018-12-25 12:30 +0100
    Re: RFC: proposed fix for CVE-2018-19518 in uw-imap Roberto C. Sánchez <roberto@debian.org> - 2018-12-28 05:30 +0100
      Re: RFC: proposed fix for CVE-2018-19518 in uw-imap Roberto C. Sánchez <roberto@debian.org> - 2018-12-28 15:30 +0100
      Re: RFC: proposed fix for CVE-2018-19518 in uw-imap Tomas Bortoli <tomasbortoli@hotmail.it> - 2018-12-28 19:30 +0100
  Re: RFC: proposed fix for CVE-2018-19518 in uw-imap Ola Lundqvist <ola@inguza.com> - 2018-12-28 21:50 +0100
  Re: RFC: proposed fix for CVE-2018-19518 in uw-imap Roberto C. Sánchez <roberto@debian.org> - 2018-12-29 16:30 +0100
    RE: RFC: proposed fix for CVE-2018-19518 in uw-imap COSTEY Anthony <a.costey@caenlamer.fr> - 2018-12-29 17:10 +0100
    Re: RFC: proposed fix for CVE-2018-19518 in uw-imap Salvatore Bonaccorso <carnil@debian.org> - 2018-12-30 09:40 +0100
      Bug#914632: RFC: proposed fix for CVE-2018-19518 in uw-imap Magnus Holmgren <holmgren@debian.org> - 2019-02-24 20:40 +0100

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