I was rading my companies application security guide lines and I came across this 
... Enables "stealth commanding" i.e. the insertion of 
special control or escape characters in data input ...
and "%" which invokes system level commands in Perl
I always thought that % was used to denote that a variable is a hash?
Is there some other use of % that can be "exploited"?

In reply to Acceptance meta code embedded within input data? by Anonymous Monk

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