Comprehensive Guide on Medusa – A Brute Forcing Tool

Hello friends!! Today we are going to discuss – How much impactful Medusa is in cracking login credential of various protocols to make unauthorized access to a system remotely. In this article we have discussed each option available in Medusa to make brute force attack in various scenario. 

Table OF Content

  • Introduction to Medusa and its features
  • Password Cracking For Specific Username
  • Username Cracking for Specific Password
  • Cracking Login Credential
  • Making Brute Force Attack on Multiple Host
  • Attacking on Specific Port Instead of Default
  • NULL/Same as Login Attempt
  • Save logs to Disk
  • Stop on Success
  • Suppress Startup Banner
  • Verbose Mode
  • Error Debugging Mode
  • Using Combo Entries
  • Resuming the Brute Force Attack

Introduction to Medusa and its features

Medusa is a speedy, parallel, and modular, login brute-forcer. The goal is to support as many services which allow remote authentication as possible. The author considers following items as some of the key features of this application:

  • Thread-based parallel testing. Brute-force testing can be performed against multiple hosts, users or passwords concurrently.
  • Flexible user input. Target information (host/user/password) can be specified in a variety of ways. For example, each item can be either a single entry or a file containing multiple entries. Additionally, a combination file format allows the user to refine their target listing.
  • Modular design. Each service module exists as an independent .mod file. This means that no modifications are necessary to the core application in order to extend the supported list of services for brute-forcing.
  • Multiple protocols supported. Many services are currently supported (e.g. SMB, HTTP, POP3,  MS-SQL, SSHv2, among others)

Reference Source: http://www.foofus.net] 

Type “medusa” in the terminal without any options, it will dump all the available options it accepts along with their respective description.

Syntax: Medusa [-h host|-H file] [-u username|-U file] [-p password|-P file] [-C file] -M module [OPT]

  -h [TEXT]            : Target hostname or IP address

  -H [FILE]             : File containing target hostnames or IP addresses

  -u [TEXT]            : Username to test

  -U [FILE]             : File containing usernames to test

  -p [TEXT]            : Password to test

  -P [FILE]             : File containing passwords to test

  -C [FILE]             : File containing combo entries. See README for more information.

  -O [FILE]             : File to append log information to

  -e [n/s/ns]        : Additional password checks ([n] No Password, [s] Password = Username)

  -M [TEXT]          : Name of the module to execute (without the .mod extension)

  -m [TEXT]          : Parameter to pass to the module. This can be passed multiple times with a

                 different parameter each time and they will all be sent to the module (i.e.

                 -m Param1 -m Param2, etc.)

  -d                          : Dump all known modules

  -n [NUM]          : Use for non-default TCP port number

  -s                          : Enable SSL

  -g [NUM]           : Give up after trying to connect for NUM seconds (default 3)

  -r [NUM]           : Sleep NUM seconds between retry attempts (default 3)

  -R [NUM]          : Attempt NUM retries before giving up. The total number of attempts will be NUM + 1.

  -c [NUM]           : Time to wait in usec to verify socket is available (default 500 usec).

  -t [NUM]           : Total number of logins to be tested concurrently

  -T [NUM]            : Total number of hosts to be tested concurrently

  -L                          : Parallelize logins using one username per thread. The default is to process

                 the entire username before proceeding.

  -f          : Stop scanning host after first valid username/password found.

  -F                          : Stop audit after first valid username/password found on any host.

  -b                          : Suppress startup banner

  -q                          : Display module’s usage information

  -v [NUM]           : Verbose level [0 – 6 (more)]

  -w [NUM]         : Error debug level [0 – 10 (more)]

  -V                         : Display version

  -Z [TEXT]            : Resume scan based on map of previous scan

As said above medusa is a brute forcing tool and you can use -d option to identify all available modules it contains.

Password Cracking For Specific Username

Medusa is very impactful tool and also quit easy to use for making brute force attack on any protocol.

Assume you want to crack password for ftp (or any other) whose username is with you, you only wish to make a password brute force attack by using a dictionary to guess the valid password.

At that moment you should go with following command where -u option enables username parameter and -P options enable dictionary for password list.

As you can observe it has found 1 valid password: 123 for username: raj for FTP login.

Username Cracking for Specific Password

Assume you want to crack username for ftp (or any other) whose password is with you, you only wish to make a username brute force attack by using a dictionary to guess the valid username. Hence it is vice-versa situation compare to above situation.

At that moment you should go with following command where -U option enables dictionary for username list and -p options enable password parameter.

As you can observe it has found 1 valid username: raj for password: 123 FTP login.

Cracking Login Credential

Suppose you want to crack username and password for ftp (or any other), wish to make username and password brute force attack by using dictionary to guess the valid combination

At that moment you should go with following command where -U option enables dictionary for username list and – P options enables dictionary for password list.

As you can observe it has found 1 valid username: raj for password: 123 FTP login.

Making Brute Force Attack on Multiple Host

If you want to use a user-pass dictionary on multiple host in a network then you can use -M option that enables the host list parameter and make brute force attack using same dictionary and will try same number of login attempt on each HOST IP mention in the host list.

Here you can observe I had saved two host IP in a text file and then use following command to make brute force attack on multiple host by using same dictionary.

As you can observe it has found 2 valid FTP logins on each Host.

If  you have multiple host IP in your host list and you want to make brute force attack only few number of host then use -T option for total number of hosts to be tested concurrently.

As you can observe from given below the 1st command make brute force attack on single Host IP where as in 2nd command it is making brute force attack on two host IP simultaneously.

Attacking on Specific Port Instead of Default

Due to security concern the network admin change the port number of a service on another port. Medusa makes brute force attack on default port of a service as you can observe in above all attacks it has automatically making attack on port 21 for ftp login.

But you can use -n option that enables specific port number parameter and launch the attack on mention port instead of default port number.

Suppose on scanning the target network I found SSH is running port 2222 instead of 22 therefore I will execute following command for ssh login attack.

As you can observe, in 1st command of medusa it fail to connect on ssh as port 22 was close and it has found 1 valid password: 123 for username: raj for SSH login @ port 2222.

NULL/Same as Login Attempt

Using option -e along with ns enables three parameter null/same as login while making brute force attack on password field.

As you can observe with every username, it is trying to match the following combination along with the password list.

User “raj” and password “” as null password

User “raj” and password “raj” as same as login

Save logs to Disk

For the purpose of the record maintenance, better readability and future references, we save the output of the Medusa brute force attack onto a file. To this we will use the parameter -o of the medusa to save the output in a text file.

Now that we have successfully executed the command, now let’s traverse to the location to ensure whether the output has been saved on the file on not. In this case our location for output is /root /log.txt.

Stop on Success 

Supoose while using host list you want to Stop brute force attack on host after first valid username/password found then you can use -f option alone with command.

Even you can use -F option to Stop audit after first valid username/password found on any host in your command.

Suppress Startup Banner

If you want to hide banner of medusa while making brute force attack then use -b option to Suppress startup banner.

Verbose Mode

There are six levels for verbose mode for examine the attack details and also contain error debug option that contain ten level for debug mode. You can use -v option for verbose parameter and -w option for error debugging parameter.

Error Debugging Mode

As said above there are level from 0-10 for examining brute force attack at each level, here you will observe the result of 0-6 is approx. same with little difference and result from of level 7-10 is approx. same but varied from 0-6 level.

Debug mode is showing waittime, socket, send data size and received data size, module detail and path.

 

Using Combo Entries

Using -c option enables combo file parameter, the combo file should have one record per line and have the values colon separated in the format host_IP:username:password. If any of the three fields are left blank, the respective information should be delivered either as a global value or as a list in a file.

The following combinations are possible in the combo file:

    host:username:password

    host:username:

    host::-

    :username:password

    :username:

    ::password

    host::password

As you can observe in the given below image, we have userpass.txt file as our combo file format and we can use it along -C option to launch brute force attack.

Resuming the Brute Force Attack

Sometime while making brute force, the attack get paused/halt or cancel accidently at this moment to save your time you can use -z option that enables resume parameter and continue the brute-forcing from the last dropped attempt of the dictionary instead of starting it from 1st attempt.

Now you can observe the output result from the given below image where after pressing ctrl C it stop the attack and then add the highlighted text in your command to resume the attack and continue it.

Repeat same as above, now compare the result after executing all three command you will notice it has continue the brute-forcing from the last dropped attempt

Author: Shubham Sharma is a Cyber security enthusiast and Researcher in the field of WebApp Penetration testing. Contact here

Comprehensive Guide on Hydra – A Brute Forcing Tool

Hello friends!! Today we are going to discuss – How much impactful hydra is in cracking login credential of various protocols to make unauthorized access to a system remotely. In this article we have discussed each option available in hydra to make brute force attack in various scenario. 

Table of Content

  • Introduction to hydra
  • Multiple Feature of Hydra
  • Password Guessing For Specific Username
  • Username Guessing For Specific Password
  • Cracking Login Credential
  • Use Verbose or Debug Mode for Examining Brute Force
  • NULL/Same as Login/Reverse login Attempt
  • Save Output to Disk
  • Resuming The Brute Force Attack
  • Password Generating Using Various Set of Character
  • Attacking on Specific Port Instead of Default
  • Making Brute Force Attack on Multiple Host

Introduction to Hydra

Hydra is a parallelized login cracker which supports numerous protocols to attack. It is very fast and flexible, and new modules are easy to add. This tool makes it possible for researchers and security consultants to show how easy it would be to gain unauthorized access to a system remotely.

It supports: Cisco AAA, Cisco auth, Cisco enable, CVS, FTP, HTTP(S)-FORM-GET, HTTP(S)-FORM-POST, HTTP(S)-GET, HTTP(S)-HEAD, HTTP-Proxy, ICQ, IMAP, IRC, LDAP, MS-SQL, MySQL, NNTP, Oracle Listener, Oracle SID, PC-Anywhere, PC-NFS, POP3, PostgreSQL, RDP, Rexec, Rlogin, Rsh, SIP, SMB(NT), SMTP, SMTP Enum, SNMP v1+v2+v3, SOCKS5, SSH (v1 and v2), SSHKEY, Subversion, Teamspeak (TS2), Telnet, VMware-Auth, VNC and XMPP.

Multiple Feature of Hydra

Since we are using GNOME build of Kali Linux therefore the “thc-hydra” package is already included by default, all we need to do, open the terminal and just type “hydra -h” and press Enter. You will welcome by its help screen.

-R :                                         restore a previous aborted/crashed session

-I :                                           ignore an existing restore file.

-S :                                          perform an SSL connect

-s :                                          PORT   if the service is on a different default port, define it here

-l LOGIN or -L :                   FILE login with LOGIN name, or load several logins from FILE

-p PASS  or -P :                  FILE  try password PASS, or load several passwords from FILE

-x MIN:MAX:CHARSET : password bruteforce generation, type “-x -h” to get help

-e nsr :                                  try “n” null password, “s” login as pass and/or “r” reversed login

-u :                                         loop around users, not passwords (effective! implied with -x)

-C FILE :                                colon separated “login:pass” format, instead of -L/-P options

-M FILE :                               list of servers to be attacked in parallel, one entry per line

-o FILE :                                write found login/password pairs to FILE instead of stdout

-f / -F :                                  exit when a login/pass pair is found (-M: -f per host, -F global)

-t TASKS :                             run TASKS number of connects in parallel (per host, default: 16)

-w / -W TIME :                   wait time for responses (32s) / between connects per thread

-4 / -6 :                                  prefer IPv4 (default) or IPv6 addresses

-v / -V / -d :                         verbose mode / show login+pass for each attempt / debug mode

-U :                                         service module usage details

server :                                 the target server (use either this OR the -M option)

service :                               the service to crack (see below for supported protocols)

OPT :                                     some service modules support additional input (-U for module help)

Reference Source: https://tools.kali.org/password-attacks/hydra

Password Guessing For Specific Username

Hydra is very impactful tool and also quit easy to use for making brute force attack on any protocol.

Syntax: hydra [[[-l LOGIN|-L FILE] [-p PASS|-P FILE]] | [-C FILE]] [-e nsr] [-o FILE] [-t TASKS] [-M FILE [-T TASKS]] [-w TIME] [-W TIME] [-f] [-s PORT] [-x MIN:MAX:CHARSET] [-SuvV46] [service://server[:PORT][/OPT]]                                                                          

Suppose you want to crack password for ftp (or any other) whose username is with you, you only wish to make a password brute force attack by using a dictionary to guess the valid password.

At that moment you should go with following command where -l option enables username parameter and -P options enable dictionary for password list.

As you can observe it has found 1 valid password: 123 for username: raj for FTP login.

Username Guessing For Specific Password

Suppose you want to crack username for ftp (or any other) whose password is with you, you only wish to make a username brute force attack by using a dictionary to guess the valid username. Hence it is vice-versa situation compare to above situation.

At that moment you should go with following command where -L option enables dictionary for username list and -p options enable password parameter.

As you can observe it has found 1 valid username: raj for password: 123 FTP login.

Cracking Login Credential

Suppose you want to crack username and password for ftp (or any other), wish to make username and password brute force attack by using dictionary to guess the valid combination

At that moment you should go with following command where -L option enables dictionary for username list and – P options enables dictionary for password list.

As you can observe it has found 1 valid username: raj for password: 123 FTP login.

Use Verbose or Debug Mode for Examining Brute Force

You can use -V option along with each command, with the help of verbose mode you can observe the each attempt for matching valid combination of username and password. If you will observe the given below image then you will find there are 5 username in user.txt file (L=5) and 5 passwords in pass.txt file (P=5) and hence the total number of login attempt will be 5*5=25.

Even you can use -d option that enables debug and verbose mode together and shows complete detail of attacking mode.

As you can observe the verbose mode is showing each attempt for matching valid credential for username and password with the help of user.txt and pass.txt as well as debug mode is showing waittime, conwait, socket, send pid and received pid

NULL/Same as Login/Reverse login Attempt

Using option -e along with nsr enables three parameter null/same as login/reverse login while making brute force attack on password field, if you will observe the given below image then you will notice that, this time L=5 and automatically P=8 which means now the total number of login tries will be 5*8=40.

As you can observe with every username, it is trying to match the following combination along with the password list.

Login “root” and pass “” as null password

Login “root” and pass “root” as same as login

Login “root” and pass “toor” as reverse of login

Save Output to Disk

For the purpose of the record maintenance, better readability and future references, we save the output of the hydra brute force attack onto a file. To this we will use the parameter -o of the hydra to save the output in a text file.

Now that we have successfully executed the command, now let’s traverse to the location to ensure whether the output has been saved on the file on not. In this case our location for output is /root /output.txt.

Resuming the Brute Force Attack

Sometime while making brute force, the attack get paused/halt or cancel accidently at this moment to save your time you can use -r option that enables resume parameter and continue the brute-forcing from the last dropped attempt of the dictionary instead of starting it from 1st attempt.

Now you can observe the output result from the given below image where after pressing ctrl C it stop the attack and then type hydra -R to resume the attack and continue it.

Password Generating Using Various Set of Character

Hydra has -x option that enables password generation option that involves following instructions:

-x MIN:MAX:CHARSET

MIN is use to specify the minimum number of characters in the password

MAX is use to specify the maximum number of characters in the password

CHARSET is use to specify a specification of the characters to use in the generation valid CHARSET values are: ‘a’ for lowercase letters, ‘A’ for uppercase letters, ‘1’ for numbers, and for all others, just add their real representation.

-y disable the use if the above letters as placeholders

Now suppose we want to try 123 as password for that I should set MIN=1, MAX=3 CHARSET 1 for generating numeric password for given username and run following command as said.

As you can observe it has found 1 valid password: 123 for username: raj for FTP login.

Now suppose we want to try abc as password for that I should set MIN=1, MAX=3 CHARSET a for generating lowercase character password for given username and run following command as said.

As you can observe it has found 1 valid password: abc for username: shubham for FTP login.

Attacking on Specific Port Instead of Default

Due to security concern the network admin change the port number of a service on another port. Hydra makes brute force attack on default port of a service as you can observe in above all attacks it has automatically making attack on port 21 for FTP login.

But you can use -s option that enables specific port number parameter and launch the attack on mention port instead of default port number.

Suppose on scanning the target network I found FTP is running port 2121 instead of 21 therefore I will execute following command for ftp login attack.

As you can observe it has found 1 valid password: 123 for username: raj for FTP login.

Making Brute Force Attack on Multiple Host

If you want to use a user-pass dictionary on multiple host in a network then you can use -M option that enables the host list parameter and make brute force attack using same dictionary and will try same number of login attempt on each HOST IP mention in the hosts list.

Here you can observe I had saved two host IP in a text file and then use following command to make brute force attack on multiple host by using same dictionary.

As you can observe it has found 2 valid FTP logins on each Host.

Suppose you had given a list of multiple targets and wish to finish the brute force attack as soon as it found valid login for any host IP, then you should use -F options which enable finish parameter when found valid credential for either host from inside the host list.

As you can observe it has found 1 valid FTP logins for 192.168.1.108 and finish the attack.

Disclaimer by Hydra – Please do not use in military or secret service organizations, or for illegal purposes.

Author: Shubham Sharma is a Technical writer, Researcher and Penetration tester contact here

Matrix: 1 Vulnhub Walkthrough

Hello friends! Today we are going to take another boot2root challenge known as Matrix. The credit for making this vm machine goes to “Ajay Verma” and it is another boot2root challenge in which our goal is to get root access to complete the challenge. You can download this VM here.

Security Level: Intermediate

Flags: There is one flag (flag.txt).

Table of contents:

  • Port scanning and IP discovery.
  • Hitting on port 80
  • Hitting on port 31337 and finding base64 encoded string
  • Decode base64 encoded string
  • Finding and downloading Bin file
  • Decoding brainfuck encoded string
  • Creating dictionary using crunch
  • SSH login brute force using hydra
  • Finding rbash
  • Escaping restricted shell environment
  • Exporting environment variables
  • Getting root access.
  • Reading the flags.

Walkthrough

Let’s start off with scanning the network to find our target.

We found our target –> 192.168.1.18

Our next step is to scan our target with nmap.

The NMAP output shows us that there are 4 ports open: 22(SSH), 80(HTTP), 31337(HTTP)

We find that port 80 is running http, so we open the IP in our browser.

We don’t find anything on the web service running on port 80. So we start enumerating the web service running on port 31337.

We take a look at the source code of the web service running on port 31337 and find a base64 encoded string.

We decode the base64 encoded string and find a hint to that is related “Cypher.matrix”.

We open “Cypher.matrix” on the web service running on port 31337 and find that it starts downloading a BIN file.

We take a look at the content of the file and find “brainfuck” encoded string.

We decode the brainfuck encoded string using this site here and find an incomplete password for the user “guest”.

As the last 2 characters are missing we create a wordlist using crunch so that we can brute force SSH login.

We use hydra to brute force ssh login using the dictionary we created earlier and find the password to be “k1ll0r7n”.

Now that we know the password we login through SSH using credentials “guest:k1ll0r7n

After logging in we try to run “ls” command but are unable to run it as we have an rbash shell.

We check the PATH environment variable and find that the path to be “/home/guest/prog”.

Now as we cannot run “ls” command we try to find commands that can run. After trying a few commands we find that we can run “echo” command. We use “echo” command to find the executables inside “/home/guest/prog” and find “vi” is available.

Now we check SHELL environment variable and find we have only rbash shell.

We run vi so that we can spawn /bin/bash and escape the restricted shell environment.

After escaping the restricted shell environment, we export /bin/bash to SHELL environment variable and “/usr/bin” directory to PATH environment variable so that we can run linux command properly.

After exporting into the environment variables, we check sudoers list and find we can directly get root shell as we have all the rights.

We are unable to execute “su” command as we haven’t exported “/bin” directory into PATH environment. We exported “/bin” directory into PATH environment variable and again ran the command to login as root using the password we find earlier.

After logging in we go to root directory and find a file called flag.txt. We take a look at the content of the file and find the congratulatory message.

Author: Sayantan Bera is a technical writer at hacking articles and cyber security enthusiast. Contact Here

Hack the Raven: Walkthrough (CTF Challenge)

Hello everyone and welcome to yet another CTF challenge walkthrough. This time we’ll be putting our hands on Raven. Raven is a Beginner/Intermediate boot2root machine. There are two intended ways of getting root and we demonstrate both of the ways in this article.

Table of contents: (Method 1)

  1. Port scanning and IP discovery.
  2. Hitting on port 80 and discovery of WordPress CMS.
  3. WPScanning the website to discover two users.
  4. Hitting and bruteforcing port 22.
  5. Enumerating the active processes using LinEnum script.
  6. Discovery of MySQL.
  7. Fetching the database username and password from wp-config.php.
  8. Using MySQL to create a UDF (user-defined function) dynamic library.
  9. Compiling UDF exploit to a shared library program.
  10. Running UDF library program into the victim’s machine.
  11. Setting sticky bit on “find.”
  12. Getting root access.
  13. Reading the flags.

Table of contents: (Method 2)

  1. Getting shell to the victim and accessing MySQL the same way till step 7 in method 1.
  2. In MySQL shell, discovering all the databases and tables.
  3. Reading table wp_users from the database wordpress.
  4. Fetching hashes from the table wp_users.
  5. Cracking the hash to get shell to the other user.
  6. Discovering python has no root required to run.
  7. Spawning root TTY using python one liner.
  8. Reading the flags.

Let’s get started then!

Discovering the active devices on a network using netdiscover and getting the IP address of our victim machine. In this case the IP address holds 192.168.1.102

Using nmap on the victim machine we got three ports open 22,80 and 111

So we instantly moved to the port 80 and discovered a website of Raven Security.

On the top right we found a tab saying “blog” and moved to the webpage only to discover that the victim’s machine had WordPress CMS installed!

So, the first idea that came to us was to run a wpscan on the webpage and see what the scan enumerates.

The results returned 2 valuable users made on the victim’s machine:

Michael and steven.

Now, to proceed further in the same port was seeing blurry to the eye so we tried hitting port 22 (SSH).

It is a fairly logical hit and try method to use the same word as both the username and password too.

We logged in to SSH with “michael” as the username and “michael” and got into the shell successfully!

Then we changed the active directory to /tmp and imported LinEnum.sh, a script to enumerate many of the basic and advanced linux details.

It was hosted in a folder on our local machine and was imported into the victim machine using wget command.

My local IP address was 192.168.1.109 in this case.

After changing the permissions of the file to executable we ran the script only to find that MySQL service was running (port 3306 is evident to that).

We found a MySQL-Exploit-Remote-Root-Code-Execution-Privesc vulnerability! (FOR MORE INFO: https://legalhackers.com/advisories/MySQL-Exploit-Remote-Root-Code-Execution-Privesc-CVE-2016-6662.html)

So, we changed the current directory to /var/www/html/wordpress and searched for the wp-config file, since it will have the password to the mysql database.

The password was found to be:

So, we searched for a UDF dynamic library exploit and it was named “1518.c” in exploit database.

https://www.exploit-db.com/exploits/1518/

The exploits run by compiling the raw C code to .so file and then transferring it to the victim machine and exploiting MySQL vulnerability.

The first step was to compile it.

We then fired up a local server and transferred this 1518.so file to the victim’s /tmp directory since it is universally readable and writable using the wget command.

<entered password>

After getting a MySQL shell, we started exploiting it using the vulnerability we just found

Now, we created a table called “foo”

In this table, we inserted the link to the 1518.so file we just imported from local machine to /tmp directory.

We dumped the same file to /usr/lib/mysql/plugin/ directory (since it was vulnerable)

In the most important step, we created a UDF function named do_system, that will invoke the code that implements the function.

Hence, we are invoking the code “chmod u+s /usr/bin/find” to set the sticky bit on “find”

Now we traversed back to the directory /tmp and executed commands using the find utility.

But since the task is also to capture all the flags we found it using the command:

Second Method

Reach to the MySQL shell as above and then follow the alternate approach.

See all the databases and dump the usernames from wp_users table in the database “wordpress”

We found two hashes but since we already know the password to Michael, we cracked steven’s password using john the ripper by pasting the hash into a text file called “hash.”

The password was found to be: pink84

Logging into steven’s shell and running sudo –l command we found that Python required no root permission to run.

So, we spawned a python teletype (PTY) using python’s one liner.

So, here it is! Two ways to root raven. Hope you found it useful.

Author: Harshit Rajpal is an InfoSec researcher and a left and right brain thinker. contact here

Related Posts Plugin for WordPress, Blogger...