jdtoronto has asked for the wisdom of the Perl Monks concerning the following question:

Esteemed Monks,

I am writing a rather large WebApp using CGI::Application, HTML::Template, Apache::Session all under mod_perl.

I wish to make the operation as secure as possible. Presently I have the following:

  1. CHAP authentication, a challenge of the day (an MD5 hash) is sent to the client, the client enters username and password in browser. The challenge, username and password are concatenated and then HASHED using MD5 by a JavaScript in the browser. The username and the HASH are returned to the server. Server takes username, gets password from database, recreates the HASH and verfies they are the same.
  2. INPUT VERIFICATION - SessionID, UserID & RunMode produce an MD5 hash as a checksum, the three values plus the checksum are encrypted using Blowfish and sent to the client as a hidden field. When it is returned the veracity of the 'secret' is tested and if it passes the session is allowed to continue.
  3. Form data is validated at the client end using JS, but is repeated again on the server.
  4. Search query fields are all tested to see that they are of the appropriate type before they are used.
  5. Updated Thanks for the reminder freddo411 this all takes place over an SSL connection.
OK, my question is, what am I missing? Is there any other technique I should be using along with these?