Re: OT, sorta: Breaking pipes?

[Chris Myers <clmmacunix () charter net>]

Do you use Perl at all with CGI scripts? If so, this is just an  
example of what might be done with anything written with custom  
scripts. In this case, it is a specific vendor, but it could happen to  
anyone who does not code diligently.

http://www.kb.cert.org/vuls/id/496064

Thank You,

Chris Myers
clmmacunix () charter net

John 1:17
For the Law was given through Moses; grace and truth were realized  
through Jesus Christ.

   Go Vols!!!!

On Oct 27, 2009, at 1:48 PM, Kurt Buff wrote:

> All,
>
> At $WORK I admin a nice Sidewinder. Works well. I like it, though I'm
> not as fully trained on it as I'd like to be.
>
> However, I'm seeing more complaints from end-users who are
> encountering web sites that issue URLs with the pipe/vertical bar -
> "|" - character embedded in them. The Sidewinder proxy denies it, as
> is proper. The latest occurrence is a really stupid State government
> web site that actually puts the pipe character at the end of the URL!
>
> For those sites that we have a business case for end-user access, I
> make an exception.
>
> IT manager now considers this an annoyance, and wants justification
> for the not allowing URLs with the character through the proxy. I tell
> him it violates the RFCs that I'm aware of (1738 and 2396 - 3986
> doesn't really deal with it, AFAICT) and he wants me to
> quantify/qualify the risk, and wants me to consider allowing that
> character universally. I told him (as I believe to be correct) that
> you can't do that without turning off the proxy entirely, which would
> be foolish in the extreme.
>
> Aside from what we (the manager and I) already know (that the pipe is
> used in scripting/shells/etc. to redirect output from one program to
> another) are there any other risks of which I'm not aware, or any
> specific attacks that I can point to that have or do use this
> character? I would think that our current understanding on this would
> be sufficient justification for keeping things the way they are, but
> apparently not.
>
> This is really silly, and frustrating for me, though I suppose many of
> you have fought the same (kinds of) battle, but any insight would
> help.
>
> Thanks,
>
> Kurt
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