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Date: Tue, 3 May 2016 21:01:43 -0700
From: Seth Arnold <>
Subject: Re: ImageMagick Is On Fire -- CVE-2016-3714

On Tue, May 03, 2016 at 08:42:30PM -0500, Bob Friesenhahn wrote:
> >This appears to be executed via:
> >
> >which tries to escape arguments using UnixShellTextEscape(). This function
> >appears to replace \`"$ chars with backslash-escaped versions. I'm not
> >sure this is a safe mechanism either.
> Please provide me with a working exploit.

Sorry, exploits aren't my strong suite.

Shells are crazy things though -- | & || && and ; make it easy to execute
additional commands. * ? {} and [] make it easy to turn "single" arguments
into many arguments or get forbidden characters from the filesystem into
the command line anyway. - can change behaviours of called programs. etc etc.

> Be aware that this quoting method is only used for the few delegates.mgk
> rules which require shell-like syntax to work. Otherwise the external
> program is run using execvp() without a shell.

Now this I love to hear. execve() makes me happy.


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