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htmltextboxasciibuffer-overflow

Entering ascii into html text box

I'm doing a cybersecurity capture the flag challenge and attempting to do buffer overflow on a server. it has an html text box that I'm trying to overflow with particular values. How can I enter ascii characters into this text box? The characters entered after a certain buffer length seem to be converted into their ascii values, so I'm trying to enter characters like NUL, EOT, etc. into the text box.

Solution

  • You can use the hex value, see this or this
    For example from python you could use something like:

    param = "\x00\x04\x03\x03"

    And then send as GET request (see urllib2 or requests or httplib2)

    From URL, before of the hex code you must add the % character

    yourpage.html/param=%00%04%03%04

    Look also this link