Category: Password cracking tools

Hello, aspiring ethical hackers. In one of our previous blogposts, you learnt about password cracking and different types of password cracking techniques. In this blogpost, you will learn about a password cracking tool called John password cracker. Originally, called John the Ripper, John password cracker is a cross-platform software and a very popular password cracker.

In one of our previous blogposts, you learnt in detail about encryption. Hashing is a method of encryption in which a plain string of text is converted into an encrypted hash. This is a one-way function and hashes cannot easily be converted back to plain string. This technique is often used for storing passwords.

Being one of the most popular password hash cracking tools, John is installed by default in Kali Linux and I will be using the same for this tutorial. To demonstrate the power of John, first we need to create a hash. This can be done using online services like md5encrypt. I copy the generated MD5 hash to a text file named hash.txt as shown below.

Then all we have to do is submit this file to John as shown below.

Then John begins to crack the hash in the file. In most of the real-world cases, this will consume lot of time. So, it is good to specify the format of the hash using the ‘–format’ option as shown below. The format of the hash can be identified using hash identification.

As you can see in the above image, John successfully cracked the password hash. Let’s add a SHA-1 hash now to the same file and try cracking it.

The list of all the hash formats John can crack are many. John can crack a number of password hashes at once. However, they should all be of same format. Let’s add another MD5 hash to the hash.txt file.

Once a hash is cracked by John, it can be viewed using the ‘–show’ option. For example, all the hashes in file “hash.txt” can be viewed as shown below.

Single mode

As already mentioned at the beginning of this article, John can use different techniques to crack password hashes. One of them is single mode. People in some cases use the username as a password (or a variation of username as password). Single mode is mostly useful in these cases. When single mode is specified, it tries all the variations of the username to crack the hash. Let’s try it out. I add a password hash along with the username to the file hash.txt.

Then, specifying single mode does this.

Wordlist mode or Dictionary mode

John can also use dictionary mode to crack the hash. I add a new hash to the file hash.txt.

Then all we need to do is specify a wordlist as shown below.

Incremental mode

If all those options fail, John still has incremental mode in which the combination of all the techniques are used. But this may take lot of time and resources.

But password cracking is all about patience. Learn how to crack hashes with hashcat.

Hello, aspiring ethical hackers. This blogpost is a complete guide to Cewl wordlist generator. Cewl stands for Custom Word List generation. It is written in ruby language. Unlike crunch that takes input from us to generate a wordlist, this tool spiders a given website to the depth specified by us and then creates a dictionary or wordlist from it. This wordlist can then be used for password cracking with tools the Brutus, Hydra, Medusa and John The Ripper. It was designed by Robin Wood based on a discussion on PaulDotCom about creating wordlists by spidering a target website.

Cewl can be downloaded from here. Kali Linux has cewl installed by default and for this tutorial we are using the same. Metasploitable 2will be used as target since it has lot of applications installed that can be used for testing it.

To use cewl, all we have to do is simply supply the URL you want to spider for as shown below.

Then it will create the wordlist for you as shown below.

Keeping the downloaded file (-k)

Specifying the ‘-k’ option the downloaded file can be saved.

Depth of spidering (-d)

When you specify a target to Cewl, it spiders to the dept of 2 by default. You can change it using this option. For example, let’s set the depth to 1.

Or 3 may be.

Minimum word length (-m)

This option can be used to set the minimum length of the passwords cewl creates. For example, nowadays, most services set the minimum length of the password to at least 5. So there’s no use creating passwords with length less than the minimum length your target has set, If you have noticed the above results, the default minimum length for cewl is 3. Let’s set it to 5 for example.

As you can see in the above image, there are no longer passwords of length less than 5.

Spidering other sites (-o)

Setting this option allows cewl to spider another external sites during spidering of the target.

Don’t scan specified paths (–exclude)

If the target website is too large, you may want to skip some paths or maybe you just want to skip some paths as they may not have any passwords. You can use this option what cewl to exclude the paths you don’t want to scan. Then paths should be supplied in a file.

–allowed

This option is used to specify regex patterns of the path to be followed. If the pattern doesn’t match, it drops the scan.

No wordlist please (-n)

If you don’t want the wordlist to be printed, you can use the “-n” option.

Saving the output (-w)

Till now, you have seen that Cewl has been printing the wordlists it creates to the terminal. The output can be copied and pasted in another file to be saved from using as a wordlist. But why take all this effort when we can just save the output to file, using the ‘-w’ option.

Use User agent (-u))

A user agent is a characteristic string that allows web server to identify the browser and operating system and we are using. You can see your user agent here. Using the (-u) option, cewl allows you to be get a specific user agent while spidering the website.

Groups of words (-g)

Setting this option allow cewl to return group of words along with single words.

Turn all generated passwords to lowercase (–lowercase)

Setting this option allows us to 16 turn all the passwords cewl generates into lower case.

Here is the result.

Include words with numbers too (–with-numbers)

While spidering, if cewl finds any words with numbers in them, it just ignores them. But many passwords contain numbers too. By setting this option, cewl collects numbers as well.

–convert-umlauts

Setting this option to while using cewl converts common ISO-8859-1 umlauts.

Include meta data too (-a)

When we set this option, Cewl includes metadata found while spidering the website apart from the words.

This metadata found is included at the end of the output files as shown below.

Save metadata found to a different file (–meta-file)

You can even save all the metadata found on the target site to a different file as shown below using the “–meta-file” option.

In the above image, you can see that cewl, while processing metadata creates a temporary file. This file known as cewl-temp.pdf is created in the /tmp directory by default. We can change the location of this file by using the “—meta-temp-dir” option as shown below.

Gather emails too (-e)

Not just metadata, you can even process emails using cewl with the ‘-e’ option.

Save collected emails in another file (–email-file)

These collected emails can also be saved in another file using the “–email-file” option.

Show the count for each word (-c)

Setting this option shows the count for each word.

Verbose mode (-v)

Just like every other tool, this tool to has verbose mode that gives detailed information.

Debug mode (–debug)

Similarly, the “–debug” option gives detailed debugging information too.

Authentication

Some sites need authentication to spider it. Cewl allows authentication of websites too.

It supports both basic authentication and digest authentication. The “auth_type” option is used to set the type of authentication. The “–auth _user” and “–auth_pass” option can be used to set username and passwords respectively.

Here’s the output.

Spidering through proxy

Spidering, no matter what the purpose is very noisy. Cewl has an option to spider through a proxy using the “–proxy_host” option.

You can even specify the port of the proxy using the “–proxy-port” option.

Cewl even has feature of authenticating to the proxy server using the “–proxy_username” and “–proxy_password” options.

Hello, aspiring ethical hackers. This blogpost is a complete guide to Hydra password cracker. Hydra password cracker runs on Linux, Windows, Solaris, FreeBSD/openBSD, QNX and macOS. Using Hydra, we can crack passwords of various protocols like Asterisk, AFP, Cisco AAA, Cisco auth, Cisco enable, CVS, Firebird, FTP,  HTTP-FORM-GET, HTTP-FORM-POST, HTTP-GET, HTTP-HEAD, HTTP-POST, HTTP-PROXY,  HTTPS-FORM-GET, HTTPS-FORM-POST, HTTPS-GET, HTTPS-HEAD, HTTPS-POST,  HTTP-Proxy, ICQ, IMAP, IRC, LDAP, MEMCACHED, MONGODB, MS-SQL, MYSQL, NCP, NNTP, Oracle Listener,  Oracle SID, Oracle, PC-Anywhere, PCNFS, POP3, POSTGRES, Radmin, RDP, Rexec, Rlogin,  Rsh, RTSP, SAP/R3, SIP, SMB, SMTP, SMTP Enum, SNMP v1+v2+v3, SOCKS5,  SSH (v1 and v2), SSHKEY, Subversion, Teamspeak (TS2), Telnet, VMware-Auth,  VNC and XMPP.

Hydra can be downloaded from here. This guide uses Hydra installed on default in Kali Linux and Metasploitable2 as target.

Single username (-l) and Password (-P)

If you want to check a single username and password with Hydra, the syntax is given below. Here we are testing the credentials on target system’s FTP server. This is normally useful when we have a general idea about at least one credential pair.

Hydra will test this credential and come with a result. Here it is found this credential accurate.

What if you can’t guess a password or have no knowledge about at least one credential pair. Then we need to test a large list of credentials using brute forcing by using a wordlist.

Specifying wordlist for usernames (-L) and passwords (-P)

You can specify wordlist containing usernames using the (-L) option and specify the wordlist containing passwords using the (-P) option as shown below.

Here, I am suing the same wordlist for both username and passwords. “Metsaploitable.txt”. These wordlists are normally created or obtained during the enumeration stage. For example, we obtained this during SMB enumeration of the target. Hydra found three credentials valid from this wordlist.

Restore a cancelled session (-R)

Sometimes we may need to test a large wordlist, with thousands of credentials in it. This may obviously take a lot of time and we may have to hit “CTRL+C” sometimes to cancel the session or maybe a power cut ended our scan abruptly.

Do we have to start from the beginning again? Don’t worry. You can restore the session from where you stopped in Hydra as shown below.

RIgnore the previous session (-I)

What if we don’t want to restart that session and to start a session afresh. We can just use the ignore (-I) command which asks it to ignore the previous session.

Scanning unconventional ports (-s)

You know every service has a default port on which it runs. For example, FTP (21), Telnet (23), and HTTP (80) etc. Sometimes administrators configure this service to run on unconventional ports to make them less conspicuous. Using Hydra we can even run password attack on these ports using the (-s) option. For example, imagine FTP is running on the port 2121 and not 21.

Target has SSL enabled (-S)

Using Hydra, we can connect using SSL with this option.

If the service has an old version of SSL, we can use the  “-O” option.

Additional checks (-e)

Using this option, you can check accounts for null passwords (n), using username as password (-s) and using password as username and vice versa (-r).

Combo (-C)

Sometimes, instead of an usual wordlist, we have wordlists that have credentials in “login:pass” format as shown below.

If we want to use this type of wordlist, you can use this option.

-U

When you are using a wordlist with Hydra, by default it checks all passwords for the first username and then tries the next username. Using this option, we can loop around the passwords. The first password is checked for all the usernames and then it moves to next password and does the same.

Stop after getting the first successful pair of credentials (-f)

This option (-f) makes Hydra stop password cracking as soon as one successful pair of credentials are found.

Target multiple servers (-M)

Hydra allows us to perform password cracking on multiple servers at once. We need to provide a file containing IP addresses of the targets.

Stop after getting once successful pair on multiple servers (-F)

Setting the ‘-F’ option, Hydra stops after getting the first successful pair of credentials on multiple servers.

Saving the output (-o)

Till now, we have seen Hydra showing output on stdout. However, with the “-o” option, we can save the output of the tool to a file.

Format of the output file (-b)

Hydra allows you to save output in three formats, although the default format is text. It also allows you to save output in Json and Json v2 format.

Number of tasks (-t)

Tasks are number of persistent connections Hydra makes while testing. By default, it makes 16 tasks, but this can be changed using this option. For example, let’s set it to 19.

Module specific options (-m)

This option allows us to set module specific options. For example, FTP module in Hydra doesn’t have any module specific options. But other modules like HTTP have it. All the options for a specific module can be seen using the -U option. For example, lets change the option for http-get.

Waiting time (-w)

Hydra waits for 32 seconds for receiving responses for it queries. This option can be used to change this time. For example, let’s set it to 10 seconds.

Waiting time for login attempts (-c)

This option can be used set the waiting time for login attempts Hydra performs. It is useful only when a low task time is used.

Verbose mode (-v) (-V)

Hydra has two verbose mode. The lowercase verbose mode is the default verbose mode in any other tool.

If you want to see each login attempt Hydra makes, you need to use the (-V) option.

That’s all about Hydra password cracker.

Hello aspiring Ethical Hackers. In our previous blogpost, you learnt what is password cracking and various techniques of cracking passwords. In this blogpost, you will learn about Brutus password cracker, one of the popular tools that is used for cracking passwords.

Brutus is a password cracking tool that was actually designed to test for default credentials for routers . It was made public way back in October 1998 but it is still popular in present time. It is a portable password cracking tool and there is no need of installing it. It can be downloaded from here. It works only on Windows and supports cracking passwords of various protocols. They are,

• HTTP (Basic authentication)
• HTTP (HTML form/CGI)
• POP3
• FTP
• SMB
• Telnet

After downloading, we just need to extract the contents of the archive.

To run Brutus, click on the BrutusA2 application file.

It has three modes of operation. They are, wordlist, brute force and combo list where credentials are given as username/password pairs.

For the purpose of demonstration, let’s try to crack FTP password of Metasploitable 2. I will be using the wordlist mode of attack for this. This wordlist was created while performing SMB enumeration of the target. Wordlists can also be generated using tools like Crunch, Cewl etc. After specifying the wordlist, I just need to click on “Start” to begin cracking passwords.

As the tool continues to crack credentials, any positive authentication results will be displayed as soon as they are found. In our current example, Brutus successfully extracted three credentials. They are,

• user:user
• postgres:postgres
• msfadmin:masfadmin

Let’s use them to login into our target.

Successful. Similarly Brutus password cracker can be used to brute force credentials too.