I agree that scripts *should* use taint, but what if they don't ?
Then they don't, and take a risk. I don't find, in general, the argument "what if people ignore the safety devices we give them?" very valid.
http://www.securityfocus.com/archive/1/317234, which to my reading looks like a dodgy old CGI script that would cease to be exploitable if the Perl interpreter had poisoned null countermeasures.
From the description of the code, it seems that 1) the code doesn't use taint - the substitution on the cookie failed, so the cookie would still have been tainted. 2) the cookie is interpolated into a string, then evalled. I'm pretty sure that leaves many other possibilities to execute arbitrary code.
Seems like a good thing to me, maybe I will take a stab at writing a patch.
You might consider using an embedded NUL for system calls a warning - people can than use FATAL to upgrade the warning to an exception.

In reply to Re^3: Why do poisoned null attacks still work ? by JavaFan
in thread Why do poisoned null attacks still work ? by pubnoop

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