Multiple Ways to Exploiting PUT Method

Hi Friends, today’s article is related to exploiting the HTTP PUT method vulnerability through various techniques. First we will determine if the HTTP PUT method is enabled on the target victim machine, post which we will utilize several different methods to upload a Meterpreter reverse shell on the target and compromise the same.

Table of Content 

  • Introduction to HTTP PUT Method
  • Scanning HTTP PUT Method (Nikto)
  • Exploiting PUT Method Using Cadaver
  • Exploiting PUT Method Using Nmap
  • Exploiting PUT Method Using Poster
  • Exploiting PUT Method Using Metasploit
  • Exploiting PUT Method Using Burpsuite
  • Exploiting PUT Method Using Curl

Introduction to HTTP PUT Method

PUT method was originally intended as one of the HTTP method used for file management operations. If the HTTP PUT method is enabled on the webserver it can be used to upload a malicious resource to the target server, such as a web shell , and execute it

As this method is used to change or delete the files from the target server’s file system , it often results in arise in various File upload vulnerabilities , leading the way for critical and dangerous attacks .As a best practice , the file access permissions of the organizations’ critical servers should be strictly limited with restricted access to authorized users, if in case the organization absolutely MUST have these methods enabled.

Note : In this tutorial we are using a Vulnerable target machine for Pentesting purposes and to illustrate the use of various tools . This is purely meant for educational purposes in the testing environment and should not be used in Production environment without the authorized permissions from the relevant authorities/management.

Requirements 

Target: Metasploitable 2

Attacker: Kali Linux machine

Let’s Begin!!!!

Boot your Kali Linux machine (IP : 192.168.1.105) and in parallel, type victim IP as 192.168.1.103 in the Firefox browser and click on WEBDAV. As we can see from the screenshot it is listing only the parent directory. 

First of all we need to ensure that the vulnerable target machine has the HTTP PUT method allowed for us to upload malicious backdoors.In order to confirm the same , we need to scan the target using Nikto .

Nikto is a popular Web server scanner that tests Web servers for dangerous files/CGIs, outdated server software and other issues. It also performs generic and server type specific checks.Below is the command to scan the URL:

Upon running the above command , we can observe that the highlighted part in below screenshot displays that HTTP PUT method is allowed. Now let’s hack the vulnerable target machine by uploading the PHP malicious file ,using the various techniques shown in upcoming sections.

Prepare the malicious file to be uploaded with msfvenom :

Msfvenom can be used to create PHP meterpreter payload that gives us a reverse shell. Execute the following command to perform the same

Copy the code from <?php to die() and save it in a file with .php extension as shell.php file , on the desktop .This will be utilized later in the upcoming sections , to upload the file on web server.

In parallel, load the metasploit framework by typing msfconsole on a new terminal and start multi/handler.This will be utilized in the later part of the section

Cadaver

Cadaver is a command line tool pre-installed in the Kali machine that enables the uploading and downloading of a file on webdav.

Type the target host URL to upload the malicious file , using the command given below.

Now once we are inside the victim’s directory, upload the file shell.php from the Desktop to the target machine’s path, by executing the below command :

To verify whether the file is uploaded or not, run the URL: 192.168.1.103/dav/ on the browser. Awesome!!! As we can see , the malicious file shell.php has been uploaded on the web server.

Now, let’s launch Metasploit framework and start a handler using the exploit/multi/handler module. Assign the other values like the LHOST and LPORT values to the Kali machine’s IP and port to listen on , respectively. Once done, execute by running the command exploit to start listening for the incoming connections.

Press Enter and we will observe that the reverse TCP handler has been started on Kali IP 192.168.1.105:4444.

Now go back to the previously uploaded shell.php file and click on the same.Once run , we will get TCP reverse connection automatically on the meterpreter shell. Further run the sysinfo command on the meterpreter session to get machine OS / architecture details.

 

Nmap

Nmap is an opensource port scanner and network exploitation tool.If PUT Method is enabled on any webserver, then we can also upload malicious file to a remote web server with the help of NMAP.Below is the command to configure the same . We must specify the filename and URL path with NSE arguments .In parallel , prepare the malicious file nmap.php to upload to target server.

As seen from the below screenshot , nmap.php file has been uploaded successfully.

Type the same URL in browser 192.168.1.103/dav and execute the same. As evident from the screenshot , the file nmap.php has been uploaded on the web server.

Simultaneously, open metasploit MSF console and use multi/handler; then go back to previously uploaded nmap.php file and run it. As can be seen below, this will give us a meterpreter session.

Poster

Poster is a Firefox Add-on and a developer tool for interacting with web services to let the end user trigger the HTTP requests with parameters like: GET, POST, PUT and DELETE and also enables to set the entity body, and content type

Prepare the malicious file poster.php that you would like to upload to the target machine. Install the Poster plug-in from Firefox Add-on. Click on the tools from the menu bar. And then click on Poster from the dropdown menu. A following dialog box will open. Type the URL as mentioned in the screenshot and provide the path of the malicious file to be uploaded via Browse option and finally click on PUT action.

Type the same URL in browser 192.168.1.103/dav and execute the same. As evident from the screenshot , the file poster.php has been uploaded on the web server.

Simultaneously, open metasploit MSF console and use multi/handler; then go back to previously uploaded poster.php file and run it. This will give us a meterpreter session.

Burpsuite

Burpsuite is one of the most popular proxy interception tool whose graphical interface can be effectively utilized to analyze all kind of GET and POST requests.

Configure the manual proxy settings of end users’ browser so as to intercept the GET request Browse the URL http://192.168.1.103 but don’t hit ENTER yet . In parallel , let us navigate to the Burpsuite Proxy tab and click Intercept is on option under the Intercept sub-option , to capture the request. As soon we hit ENTER in the users’ browser , we will be able to fetch the data under the intercept window.

Now right click on the same window and a list of multiple options will get displayed. Further click on Send to repeater.

 

In the below highlighted screenshot , we will observe two panels – left and right for the HTTP Request and HTTP Response respectively . The GET method can be observed in the HTTP request and we will now replace GET with the PUT method in order to upload the file with name burp.php comprising of malicious content/code.

Type PUT /dav/burp.php HTTP/1.1 in the header and then paste the php malicious code starting from <?php to die() at the end of the request, as shown below .This will upload the burp.php file under the dav directory through PUT request.

Verify and confirm the file upload by browsing the same URL 192.168.1.103/dav in the end users’ browser and we can see burp.php file has been uploaded in the /dav directory of the web server.

Simultaneously, open metasploit MSF console and use multi/handler; then go back to previously uploaded burp.php file and run it. This will give us a meterpreter session.

Metasploit

Metasploit Framework is a well known platform for developing, testing, and executing exploits. It is an open source tool for performing various exploits against the target machines. This module can abuse misconfigured web servers to upload and delete web content via PUT and DELETE HTTP requests. Set ACTION to either PUT or DELETE. PUT is the default.

Metasploit has in-built auxiliary modules dedicated to scan HTTP methods and gives us the ability to PUT a file with auxiliary/scanner/http/http_put.Below are the commands to accomplish same

Type the same URL in browser 192.168.1.103/dav and execute the same. As evident from the screenshot , the file meter.php has been uploaded on the web server.

 

Simultaneously, open metasploit MSF console and use multi/handler; then go back to previously uploaded meter.php file and run it. This will give us a meterpreter session.

 cURL

cURL is a well-known command line tool to send or receive the data using the URL syntax and is compatible with various well-known protocols (HTTPS, FTP, SCP, LDAP, Telnet etc.)

To exploit PUT method with cURL, the command is:

Type the same URL in browser 192.168.1.103/dav and execute the same. As evident from the screenshot , the file curl.php has been uploaded on the web server.

 

Simultaneously, open metasploit MSF console and use multi/handler; then go back to previously uploaded curl.php file and run it. This will give us a meterpreter session.

Author: Ankur Sachdev is Information Security consultant and researcher in the field of Network & WebApp Penetration Testing . Contact Here

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