Ah k, in this case, the content of $shellstring is tainted. This means that $shellstring obtains its value from a source outside of your script. If you are ____absolutely___ sure that this string contains what you think it does, you can do ($shellstring) = $shellstring =~ m#^(.*)$#; before sending it through the backticks. This will untaint the value. Please note that under the rarest conditions should data simply be untainted as such. This just defeats the purpose of taint, and it's rare that such a method should be used. If you cannot trust that $shellstring contains undamaging data, then you need to come up with a regex to ensure that the string is safe.

I am telling myself that the string cannot be trusted since it appears to be coming from an outside source. Mind posting the code where $shellstring is generated?

If the above content is missing any vital points or you feel that any of the information is misleading, incorrect or irrelevant, please feel free to downvote the post. At the same time, please reply to this node or /msg me to inform me as to what is wrong with the post, so that I may update the node to the best of my ability.

In reply to Re^3: How to call external scripts from a CGI-script in taint mode? by Coruscate
in thread How to call external scripts from a CGI-script in taint mode? by professa

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