In a message dated: Thu, 07 Mar 2002 08:36:13 EST
Benjamin Scott said:

>  Using this feature, an HTML form variable called "foo" results in a
>language variable called "$foo" (in Perl, at least).  So the attacker
>submits the "form" with extra variables that do things like change your
>path, shell, internal authentication variables, etc., etc.  Basically, the
>attacker can modify your program's state at will.

I don't think that's true.  Yes, you can set variables like that, but 
you can also turn that off and state explicity what variables get set 
from the HTML form.

Also, things like path, shell, and other environmental variables are 
all set using the global "%ENV" hash, which *should* be cleared out 
and set to known, safe, and accepted defaults. Perl also has 
"taint-checking" available which should always be used for stuff like 
this.

While I agree that Perl has many of the "features" you're complaining 
about, it is also completely possible to use them in a safe and 
consistent manner without getting into trouble.  Again, it comes down 
to safe programming practices.  If you know what you're doing, you're 
fine, if you don't, then you shouldn't be trying to pass as someone 
who does.

Cars are completely safe if used properly.  There are a lot of people 
on the road who claim to be and attempt to pass for someone who knows 
what they're doing and don't.  Because of them, the rest of us pay 
exhorbitant insurance rates :)
-- 

Seeya,
Paul



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