And if the user decides to type '|rm -rf' as an argument to a perl script, they could just as easily type 'rm -rf' at that same command line.

What about when the script runs as a different user than the one calling the script? This could be used to run a command with greater priviledge than one normally has.

For example, given mysetuid.pl 

print <>;

[download]

An attack: 

mysetuid.pl 'cat /etc/shadow |'

[download]

Well, at least taint catches this problem: 

Insecure dependency in piped open while running with -T switch

[download]

Update: Oops, I guess just /etc/shadow would have worked in this case!

In reply to Re^4: On being 'critical' by ikegami
in thread On being 'critical' by herby1620

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