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Intruder payload bug - square symbols between every character

pen | Last updated: Oct 04, 2017 09:43AM UTC

Every intruder attack include square blocks between every characker of payload. This happened sometimes, but now it's important case so i have to figure out why this happens here is pic: http://pl.tinypic.com/view.php?pic=n46xqq&s=9#.WdSslNFpGUk

PortSwigger Agent | Last updated: Oct 04, 2017 09:49AM UTC

Hi Pen, Thanks for your inquiry. That looks like UTF-16 encoding. The square block is used when the display font doesn't have a glyph for the character. You can see the raw value in hex view; I expect it is 00. This leads to the question of why UTF-16 encoding is in use. How did you set up the payloads? Sometimes copy & paste can result in unwanted UTF-16 encoding. Alternatively, this could be something to do with the request. You've obfuscated this in your screenshot. How was the request generated? Has this come from a Windows client application through Burp Proxy? Also, I'd be interested to see the headers.

Burp User | Last updated: Oct 04, 2017 11:03AM UTC

I found that, if I paste payloads manually (copy, paste) everything's fine. But if i load payloads by [Load ...] button and choose text file, then the attack are broken.

PortSwigger Agent | Last updated: Oct 04, 2017 11:06AM UTC

Hi Pen, Ok, that text file must be UTF-16 encoded. You can use a tool like GNU recode to change that - UTF-8 probably suits your needs better. Please let us know if you need any further assistance.

Burp User | Last updated: Oct 04, 2017 12:06PM UTC

Everything's good now. It was confusing that in payload tab in Intruder every payload was presented fine. You can close the topic, thanks.

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