[kwlug-disc] Vulnerability in bash

[William Park]

On Fri, Sep 26, 2014 at 11:27:55AM -0400, Giles Malet wrote:
> On 14-09-25 07:18 PM, William Park wrote:
> >If the command is built-in, then shell runs it.
> 
> We're getting somewhat off topic, but bash will start subshells for certain
> loops. I can't remember off the top of my head which, but I know to be
> carefully of variable assignment within a loop, since if it's done in a
> subshell the assignment is lost.
> 
> Some thing like:
> 
> A="a"; loop ... A=b ... end loop; echo $A
> 
> produces "a", not "b", since that second assignment is lost.

That would be if the loop is part of pipe, because each part is separate
process, ie. fork/exec with consecutive parts connected to each other by
pipe.

> 
> But it's true what people have said: because of all this your running shell
> is probably pretty safe from being 0wned; subshells are vulnerable, unless
> you have a new binary.
> 
> g
> 
> 
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