How do I expose invisible characters in web forms?

April 20, 2010 7:46 AM

How do I expose invisible characters in web forms?

I just got burned with my company newsletter system which crapped out un-rendered HTML code to hundreds of thousands of recipients because there was a carriage return in the subject line submitted to the mailing software. I don't know how it got there.

1) Is it normal web security that these types of invisible characters are stripped from submitted input?

2) Is there any Firefox add-on that will expose these things to me?

Thank you for your help!

posted by ao4047 to computers & internet (2 answers total)

Your newsletter software is where the stripping-out should have occurred. It's not a security issue, it's just a bug. It just didn't occur to the author that a carriage return might break the emails.

I know this advice will be of little use after the fact, but in future you should send the newsletter to a couple of test accounts before sending it to the rest of the world.
posted by le morte de bea arthur at 7:56 AM on April 20, 2010 [1 favorite]

I think the carriage returns will survive a copy-paste operation, so you could check in another application: select all inside the text box, copy, and paste. It's likely that the reverse process is how it got in the text box to begin with.
posted by caaaaaam at 12:39 PM on April 20, 2010