Beefy Boxes and Bandwidth Generously Provided by pair Networks
XP is just a number

Comment on

( #3333=superdoc: print w/replies, xml ) Need Help??
A quick cursory look of your code doesn't reveal much ... It doesn't look as if you are running under strict as there doesn't appear to be any definition of scope of some of your variables. Nevertheless, the snippet you have given doesn't show enough for any judgement to be made of its 'fitness' for any given task - There is no indication of where you are deriving some of your values from, in particular, $tempUID and $call, without which any assessment of security tightness of your code would be flawed.

A general pragma to remember with regard to CGI security is to never trust anything which comes from the browser - Irrelevant of whether it be query arguments, cookie data or user submitted information, don't trust it! This is vitally important where any of the submitted information may be used to manipulate the filesystem or process tree directly - In such instances, you should be excluding everything and then selectively permitting that which is vetted and permissable. This can lead to a great deal of code overhead but given the consequences of a failure in security, this is a little price to pay in development time.

With regard to open and security inherit to the command itself, this comes down very much to the arguments which are passed to it - There has previously been the discussion on the 2-argument invocation of open with specific reference to passed arguments. But at the end of the day, the security concerns will center on how the data is parsed and vetted prior to being passed to open - Has the data been checked for shell escape characters? Does the target file to be opened exist? Is the target file a directory or symbolic link? Are the permission and ownership rights of the target file as expected and allowed? The list goes on ...

In short, limit the allowable parameters, code defensively and don't trust anything sent from the browser.


perl -e 's&&[@.]/&&s&.com.&_&&&print'

In reply to Re: Security with open() in CGI scripts by rob_au
in thread Security with open() in CGI scripts by Coplan

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, 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, 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.
  • Log In?

    What's my password?
    Create A New User
    and all is quiet...

    How do I use this? | Other CB clients
    Other Users?
    Others taking refuge in the Monastery: (4)
    As of 2018-05-21 19:08 GMT
    Find Nodes?
      Voting Booth?