John The Ripper Cracking Rar Password
Marion Loyd
Figure 2 illustrates using the unshadow command. This is distributed with John the Ripper in most packages. It combines the contents of /etc/passwd and /etc/shadow on a Linux VM, in this case, Kali. Then, we used the john command and specified the format -- in this case, the crypt mechanism. Since we haven't told it what cracking mode to use, John begins with single crack and then proceeds to wordlist -- none was specified, so it used the default. Ultimately, it will move to incremental mode.
In a more complicated example, Figure 3 shows an attempt at cracking Microsoft Windows passwords. As with the Linux example, passwords must be put into a format John the Ripper can understand. To accomplish that, we used PwDump v8.2.
These values are fed into John the Ripper to crack in Figure 4. We specified wordlist mode and instructed it to use rockyou.txt, one of the built-in wordlists that comes by default with most security-focused Linux distributions. Note that you may need to extract the text file first. The passwords were set to weak values -- dictionary words in all cases -- to enable the cracking to complete quickly. These two examples demonstrate the most universally applicable and most basic usage of John the Ripper. For more advanced usage, you may need to get a little creative. Sometimes, the format of stored password values you can obtain are not in one of the formats supported by John out of the box. With a few clever modifications, however, you can convert to one of those with a little research.
First released in 1996, John the Ripper (JtR) is a password cracking tool originally produced for UNIX-based systems. It was designed to test password strength, brute-force encrypted (hashed) passwords, and crack passwords via dictionary attacks.
Some of the key features of the tool include offering multiple modes to speed up password cracking, automatically detecting the hashing algorithm used by the encrypted passwords, and the ease of running and configuring the tool making it a password cracking tool of choice for novices and professionals alike.
I've seen John the Ripper mentioned a lot for cracking passwords, I've gotten as far as getting a build (1.7.9-jumbo-7 [macosx-x86-64]) installed. I have a word list ready and a vague idea of what my pass could be, I'm just not sure where to go from here.
No, not if you have a targeted list. I tested this on a password protected rar file i had someone create. I extracted the hash & ran john againt it. It ran for a solid 36 hours attempting a bruteforce in iteration mode. John never found it. Using a custom list I cracked the hash in 36 minutes.
This expands into 19 different hashdumps including des, md5, and ntlm type encryption. Each of the 19 files contains thousands of password hashes. This should be a great data set to test our cracking capabilities on.
Anyone know the usage/commands for zip2john/rar2john. I have the bleeding-jumbo version of John the ripper installed. I have a my password locked zip file (file.zip) and a unzipped word list (Rocktastic12a).
So again, once we are past the wordlist approach and we need to start brute-forcing, things get time consuming. For an 8 character password without any policy limiting the possible permutations, we are already talking about 3'025'989'069'143'040 possible passwords! At a rate of 1.5 Million passwords per second (that's what the 8 GPU server achieved using John the ripper), it would still take about 64 years to test all possible permutations for a single user. of course you might get lucky and your first guess is the right one, but you can see where this is going. On average this means, that an 8 character password will be cracked within about 32 years of calculating hashes on the before mentioned system with 8 quite fancy (by today's standards) GPU's. So if you have a cluster of 32 of these machines, you may be able to crack the password within less than 2 years for sure. BUT: keep in mind the power consumption and the cost involved with this: the 8 GPU machine consumes 2800 Watts while calculating password hashes at the said 1.5 Million passwords per second. Running such a system for 32 years at a power cost of 18 cents per kWh would cost you $141'281. This number does not change if you add more systems to your cluster. You may get there faster, but you will still use the same amount of energy. If you need to cool your server with an AC, you can even multiply this number by about 1.5 to take the power consumption of your AC into account as well. And this number is only for the AVERAGE cost, not the maximum possible cost! So at the end of the day, if you just want to hack somebody's password in order to extort money from that person or company, make sure they have enough money to give and that their data is worth enough before you spend all that money an cracking a password. also make sure you get enough machines so you can beat the target's password lifecycle ;)
We know the importance of John the ripper in penetration testing, as it is quite popular among password cracking tool. In this article, we are introducing John the ripper and its various usage for beginners.
John the Ripper is a free password cracking software tool developed by Openwall. Originally developed for Unix Operating Systems but later on developed for other platforms as well. It is one of the most popular password testings and breaking programs as it combines a number of password crackers into one package, autodetects password hash types, and includes a customizable cracker. It can be run against various encrypted password formats including several crypt password hash types commonly found in Linux or Windows. It can also be to crack passwords of Compressed files like ZIP and also Documents files like PDF.
In this mode John the ripper uses a wordlist that can also be called a Dictionary and it compares the hashes of the words present in the Dictionary with the password hash. We can use any desired wordlist. John also comes in build with a password.lst which contains most of the common passwords.
I have a computer from the 1990s. It has an (extent) EFS file-system which cannot be wrote to in linux, so i cannot reset the password manually. So i have to crack my password. For this I am trying to use John the ripper.
Where as we see John managed to crack the password of the user root as it was included in the wordlist used.
If you would like to print all the passwords John managed to crack you may run john --show unshadowed.txt and you will get something like:
John the Ripper is a free password cracking software tool.[3] Originally developed for the Unix operating system, it can run on fifteen different platforms (eleven of which are architecture-specific versions of Unix, DOS, Win32, BeOS, and OpenVMS). It is among the most frequently used password testing and breaking programs[4] as it combines a number of password crackers into one package, autodetects password hash types, and includes a customizable cracker. It can be run against various encrypted password formats including several crypt password hash types most commonly found on various Unix versions (based on DES, MD5, or Blowfish), Kerberos AFS, and Windows NT/2000/XP/2003 LM hash. Additional modules have extended its ability to include MD4-based password hashes and passwords stored in LDAP, MySQL, and others.[5]
John also offers a brute force mode. In this type of attack, the program goes through all the possible plaintexts, hashing each one and then comparing it to the input hash. John uses character frequency tables to try plaintexts containing more frequently used characters first. This method is useful for cracking passwords that do not appear in dictionary wordlists, but it takes a long time to run.
We were successful in cracking the password for the IEUser and the Administrator. Both of these are the same Passw0rd! which is the default password used on the virtual box Windows 10 machine. It is cracked very quickly just a few seconds.
This time we will use Hashcat to crack the password, and we will use a dictionary type attack. In this case we have the rockyou.txt dictionary. A password dictionary is basically a text file with a list of words which can be used to try and crack the password. The bigger your dictionary the more chance there is of cracking the password. You can find many of these dictionaries online, sometimes they are comprised of stolen passwords from actual websites! As my chosen password was not in the standard rockyou.txt dictionary I have added it for the purposes of this tutorial.
> This patch has been tested on x86 only and does not work yet on big endian
> systems. It uses asm code for speed but a portable C version is included as
> well. The asm version checks about 150,000 passwords per second on a 1 GHz
> system. Password cracking is much easier on OpenVMS than on other systems
> since passwords are not case sensitive and limited to alphanumeric,
> '$' and '_' only.
Password-guessing tools and dictionary attacks have been around for
eons, and OpenVMS has mechanisms that can help reduce the exposure
to even poorly-chosen user passwords. In particular, the OpenVMS breakin evasion mechanisms. This breakin evasion security mechanism is enabled and operating by
default on all recent OpenVMS releases. That said, password-cracking tools -- whether this one or other of
the various options -- can be quite valuable as security auditing
tools for the system manager. In particular, these tools permit
the system manager to look for weak user passwords.
:The sources are in -VMS-patch.tar.gz
David Mathog wrote:
> On Tue, 26 Nov 2002 23:11:27 +0000 (UTC)
> jl...@gailly.OmitThisWord.net (Jean-loup Gailly) wrote:
>
>
>>I have written a patch for John the Ripper
>>to allow cracking OpenVMS (Vax and Alpha) passwords. The patch is based on
>>code from Shawn Clifford, Davide Casale and Mario Ambrogetti.
>
>
> Which is nice but of little relevance to VMS security. Only a priv'd user
> should be able to read SYSUAF.DAT, and if that user has evil intentions
> then the system is already compromised - there's no need to crack
> the password file. This contrasts with many (most?) Unix systems, where
> everybody can read the encrypted password file.
>