thanks pc88mxer, for your comments. your right that the $host is tainted and i've fixed the issue. whats more,

my $fh = new IO::File "$NSLOOKUP -type=any $host 2>&1 |";

is same as

open(my $fh, "-|", $NSLOOKUP, "-type=any", $host)
however only difference from the two is that yours is more optimised than mine. so i've decided to use yours.

if your have more ideas of improvement or security issues please let me know.

many thanks

In reply to Re^2: Insecure dependency in piped open by gugubanana
in thread Insecure dependency in piped open by gugubanana

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.