If someone has altered and replaced perl itself, then all programs, as you say, have a "huge security hole".

Dude, that was kind of his point. Any application which has dependencies has, as a potential security risk, malicious or accidental alteration of those dependencies. Fortunately, since you weren't using the MD5 for anything (except to display it), your particular implementation doesn't represent a significant risk; the point is, you can't ever say "it has no security holes".

On a side note, one of my clients uses a digest (Digest::SHA-256, in this case) for file integrity checking. As an extra layer of security, files with known digests are fed to the production tool, and its output is checked against a separate implementation of the algorithm (on an off-network machine): if ever they fail to match, the box will be marked compromised and rebuilt.

<radiant.matrix>
A collection of thoughts and links from the minds of geeks
The Code that can be seen is not the true Code
I haven't found a problem yet that can't be solved by a well-placed trebuchet

In reply to Re^4: The Importance of Being Earnest by radiantmatrix
in thread The Importance of Being Earnest by zshzn

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.