There's still danger in this, even if it's not through perl internals.

Say I have variable $chargecustomerscard which, later in the code, which actually does the monetary processing in my script. Normally, this variable is only set after the status is determined from a database query, cookie checks, etc.

Certainly this variable name is sufficiently hidden from the end user since they can't see the script. But if a more malicious user were to discover that this variable exists, and that one is populating the variable space by the methods used here, then that user could easily "overwrite" the correct value of that variable just by generating the right URL request, and cause numerous problems.

It's nearly always better to explicitly define what you are looking for than to exclude the cases you don't want to look for when it comes to security in this fashion.

-----------------------------------------------------
Dr. Michael K. Neylon - mneylon-pm@masemware.com || "You've left the lens cap of your mind on again, Pinky" - The Brain

In reply to Re: Re: Web form security by Masem
in thread Web form security by earthboundmisfit

Title:
Use:  <p> text here (a paragraph) </p>
and:  <code> code here </code>
to format your post, it's "PerlMonks-approved HTML":


  • Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!
  • Titles consisting of a single word are discouraged, and in most cases are disallowed outright.
  • Read Where should I post X? if you're not absolutely sure you're posting in the right place.
  • Please read these before you post! —
  • Posts may use any of the Perl Monks Approved HTML tags:
    a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, details, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, summary, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr
  • You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)
            For:     Use:
    & &amp;
    < &lt;
    > &gt;
    [ &#91;
    ] &#93;
  • Link using PerlMonks shortcuts! What shortcuts can I use for linking?
  • See Writeup Formatting Tips and other pages linked from there for more info.