Re: CAPTCHA system in webDNA
This WebDNA talk-list message is from 2005
It keeps the original formatting.
numero = 60818
interpreted = N
texte = Hi Bill, Your proposed method looks like a good extension of my suggestion, especially the use of a randomly generated password. [cart] creates a value that looks too much like a number sometimes, and this might encourage hackers to run a brute force test on the page that's posted in the email. I also use a technique similar to the one Dan got from Brian Fries to generate virtually unique values, but I extend it even further by making the number of characters in each generated password value a random number between (for example) 10 and 20 characters. Then the hacker has one additional variable to deal with if he tries a brute force attack. I also like your idea to disable access to the page after X attempts from the same ip address within a pre-determined time period, because that would even further deter a brute force attack. After all, the valid password is already in the URL, which means the visitor from a specific ip address *should* get the password right on his very first attempt -- but certainly after a handful of failures this page should be 'turned off' for that ip address for an hour or so, and asking the visitor to try again later. Sincerely, Kenneth Grome www.kengrome.com >-----Original Message----- >From: Kenneth Grome
>Sent: Thu, 20 Jan 2005 00:12:48 +0800 >To: "WebDNA Talk" >Subject: Re: CAPTCHA system in webDNA > >You're trying to prevent automatic email deletion from an opt-in mailing list? > >I wouldn't mess with the system you're suggesting at all. Instead >when the visitor enters his (or someone else's) email address into >the email field in your unsubscribe form, I would enter a unique >value into the 'unsubscribe' field of his database record: > >[replace db=subscribers.db&eqemaildatarq=[email]]unsubscribe=[cart][/replace] > >.. and then in the same template I would send the visitor an email >message with a URL that has that same unique value in it, like this: > > >************************************ >"Someone entered your email address into the >UNSUBSCRIBE page on our web site. If that person >was you, and if you really want to unsubscribe, just >click this link and we will unsubscribe you immediately:" > >http://domain.com/page.html?out=[cart] > >"But if you do NOT want to unsubscribe from our list, >please just ignore this message, thanks." >************************************ > > >The person who receives this email message may (or may not ) click >that link. If he clicks the link, your webdna code simply deletes >the only record in the subscribers database that has that unique >'out' value in the unsubscribe field: > >[delete db=subscribers.db&equnsubscribedatarq=[out]] > >Simple and efficient, and no images or other non-webdna tricks required. > >:) > >Sincerely, >Kenneth Grome >www.kengrome.com -- ------------------------------------------------------------- This message is sent to you because you are subscribed to the mailing list . To unsubscribe, E-mail to: To switch to the DIGEST mode, E-mail to Web Archive of this list is at: http://webdna.smithmicro.com/
Associated Messages, from the most recent to the oldest:
Hi Bill, Your proposed method looks like a good extension of my suggestion, especially the use of a randomly generated password. [cart] creates a value that looks too much like a number sometimes, and this might encourage hackers to run a brute force test on the page that's posted in the email. I also use a technique similar to the one Dan got from Brian Fries to generate virtually unique values, but I extend it even further by making the number of characters in each generated password value a random number between (for example) 10 and 20 characters. Then the hacker has one additional variable to deal with if he tries a brute force attack. I also like your idea to disable access to the page after X attempts from the same ip address within a pre-determined time period, because that would even further deter a brute force attack. After all, the valid password is already in the URL, which means the visitor from a specific ip address *should* get the password right on his very first attempt -- but certainly after a handful of failures this page should be 'turned off' for that ip address for an hour or so, and asking the visitor to try again later. Sincerely, Kenneth Grome www.kengrome.com >-----Original Message----- >From: Kenneth Grome >Sent: Thu, 20 Jan 2005 00:12:48 +0800 >To: "WebDNA Talk" >Subject: Re: CAPTCHA system in webDNA > >You're trying to prevent automatic email deletion from an opt-in mailing list? > >I wouldn't mess with the system you're suggesting at all. Instead >when the visitor enters his (or someone else's) email address into >the email field in your unsubscribe form, I would enter a unique >value into the 'unsubscribe' field of his database record: > >[replace db=subscribers.db&eqemaildatarq=[email]]unsubscribe=[cart][/replace] > >.. and then in the same template I would send the visitor an email >message with a URL that has that same unique value in it, like this: > > >************************************ >"Someone entered your email address into the >UNSUBSCRIBE page on our web site. If that person >was you, and if you really want to unsubscribe, just >click this link and we will unsubscribe you immediately:" > >http://domain.com/page.html?out=[cart] > >"But if you do NOT want to unsubscribe from our list, >please just ignore this message, thanks." >************************************ > > >The person who receives this email message may (or may not ) click >that link. If he clicks the link, your webdna code simply deletes >the only record in the subscribers database that has that unique >'out' value in the unsubscribe field: > >[delete db=subscribers.db&equnsubscribedatarq=[out]] > >Simple and efficient, and no images or other non-webdna tricks required. > >:) > >Sincerely, >Kenneth Grome >www.kengrome.com -- ------------------------------------------------------------- This message is sent to you because you are subscribed to the mailing list . To unsubscribe, E-mail to: To switch to the DIGEST mode, E-mail to Web Archive of this list is at: http://webdna.smithmicro.com/
Kenneth Grome
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