Unix password crack

Typically the maximum password length on a standard Unix system is 8 characters, although some systems or system enhancements allow up to 16 characters. Brute-force password cracking is simply trying a password of A with the given salt, folowing by B, C, and on and on until every possible character combination is tried.

It is very time consuming, but given enough time brute force cracking WILL get the password. There are a few brute-force crackers out there for Unix passwords. Any brute-force cracker will do. Dictionary password cracking is the most popular method for cracking Unix passwords.

The cracking program will take a word list, and one at a time try to crack one or all of the passwords listed in the password file. The most popular cracking utility is probably Alex Muffet's program, Crack. Crack can be configured by an administrator to periodically run and automagically mail a nastygram to a user with a weak password, or run in manual mode.

However it is probably too much program for the novice script kiddie. Jack had a number of easy-to-use features, and Solar Designer took Jack's interface and developed John. Either one is recommended. If you're going to be cracking on a DOS-based machine, use John the Ripper, otherwise either one is fine for Unix the jury is still out on which one is best for Unix, it really depends on which one you are used to using.

There are several techniques that an admin might employ to force users to use better passwords, and several different packages that could be loaded and configured onto most Unix systems to better secure the passwords. One of the first techniques is to enforce password aging. While this varies from system to system, basically password aging states that you can "expire" a password.

That way you can force a user to have to change his password periodically. The security advantage is that if the user changes their password every 30 days, that stolen password file is obsolete after a month in theory, see the next question. This alone is not real security unless it is used in conjunction with other password techniques.

Some systems allow a minimal password length to be specified, certain dictionary words to be disallowed, or even disallow perceived "crackable" passwords. This in combination with password aging can help ensure that a user's password is probably going to be aged and therefore changed before it can be cracked. Another very popular technique is called password "shadowing".

This alters the password file entry slightly:. Note the "! This means that the password is located in a different file, typically called the shadow file.

The software can be installed on Windows, macOS, and Linux. Since WFuzz uses a command-line interface, users may have to be familiar with commands to maximize the use of WFuzz. WFuzz is legal to use, provided that users limit their use of the program to the legal recovery of passwords.

Brutus can recover passwords and usernames from websites, operating systems, and other applications. True to its name, Brutus utilizes a brute-force dictionary attack to retrieve passwords. There are also multiple brute force modes that users can choose from to tweak the exact methodology by which Brutus cracks passwords.

Brutus also supports multiple connections, allowing for up to 60 simultaneous connections. The user can also tweak the precise brute force modes. Unlike most password crackers on the list, Brutus does not support any operating system other than Windows desktop. Additionally, Brutus cannot crack passwords for social media and email accounts. The program also cannot hack complex passwords that consist of numbers, letters, and symbols. Brutus is a free software that does not require command-line knowledge or familiarity from the user.

The graphics user interface allows for relatively easier use than more powerful and more technical password crackers that use only command-line interfaces. For this reason, Brutus is recommended for simple projects and users who are unfamiliar with complex interfaces. Since Brutus does not use any external files like wordlists, users will face minimal privacy issues, if any.

Additionally, the only safety concerns that users may face are hardware-related, as password crackers can be quite taxing on computers. As with all password crackers, Brutus can be used legally, provided users limit password recovery to their passwords or passwords of people who have authorized password recovery.

RainbowCrack is another password cracker tool that uses a rainbow table attack to decipher passwords in hash form. The main technique used is the time-memory trade-off technique which can be accelerated with multiple GPUs.

Users can use RainbowCrack to generate rainbow tables to be used in the password cracking process or download preexisting rainbow tables from the Internet. Alternatively, the user can download paid rainbow tables from RainbowCrack as well. There are no recorded instances of RainbowCrack gaining unauthorized access or causing crashes to computers with capable hardware.

RainbowCrack also does not store any passwords on a server that allows access or transmission to other people. L0phtCrack is an open-source password cracking tool that can be used to crack Windows passwords. The main techniques that L0phtCrack uses are the dictionary attack and the brute-force attack, which allows the program to generate and guess passwords.

In addition to password-cracking features, L0phtcrack also offers routine password security scans as a network security preventive measure. The user can choose between daily, weekly, or monthly frequency options. While formerly a paid product, L0phtCrack is now available as a free download and can be used and installed only on Windows devices.

L0phtcrack is unique in that first-time users are greeted with a simple tutorial when launching the program for the first time. Additionally, L0phtcrack also has management functions like reporting and account disabling, making the software more flexible than conventional password cracking apps. L0phtcrack also uses a graphical user interface GUI as opposed to a command line, making password recovery much easier than manually typing in commands that users will have to look up before using the software.

L0phtcrack is also legal to use as long as the passwords to be recovered are owned by the user or recovered with the consent of the password owner. OphCrack is a free, open-source password cracker that uses rainbow table attacks to decipher passwords.

The rainbow attack has been used to decipher an 8-character password in just six seconds, using a rainbow table that contains uppercase and lowercase letters and numbers. To simplify the password-cracking process, OphCrack offers a free live CD that works on Windows-based operating systems. Since Ophcrack is primarily for recovering Windows OS passwords, most users will be unable to use Ophcrack the same way other password crackers are used.

This is where the Live CD comes in, which contains a small operating system that can be run independently. The live CD should be downloaded on a different computer and transferred to a CD or other bootable drive, which will then be used on the locked computer to recover the OS password.

This preempts any privacy issues, as the public would quickly know if OphCrack has hidden code that allows it to access user files or leak cracked passwords. OphCrack is also legal and widely used by testers and network administrators to test passwords and spot weak password policies.

The software uses a command-line interface, which makes Aircrack-ng more technical, but a free live CD makes the learning process easier for users. Using Aircrack-ng to crack Wi-Fi passwords can be slightly more complicated.

To get started using THC Hydra, the software will first have to be started in monitoring mode, and drivers will have to be set up before the wireless client can be unauthenticated, which allows the pre-shared key to be identified. Aircrack-ng is primarily a network scanner that happens to have password cracking capabilities.

There are no reports of Aircrack-ng transmitting recovered or deciphered passwords, although the software has been noted to be able to transmit packets, which can be a security concern for some. As a network scanner primarily, Aircrack-ng is legal to use. Unlike most entries on the list, CrackStation does not have a standalone program installed on the computer. Rather, CrackStation is a free web-based password cracker that uses the dictionary attack technique to crack hashes, which allows the program to be used on any operating system, even on mobile.

CrackStation allows up to 20 non-salted hashes to be inputted on the interface. MD5 and SHA1 hashes are referenced with a GB lookup table that contains billion entries, while other hashes are referenced with a 19GB table that contains 15 billion entries.

The tables were filled by extracting every word from Wikipedia databases and adding passwords from all password lists that the developers could find. To use CrackStation, users can place up to 20 non-salted hashes on the website, which is a relatively simpler step than the more complex setups required for other password crackers. However, the website states that there is a possibility that connections are being intercepted by government agencies such as the NSA, which may prompt some users to opt for other tools instead.

Despite any possible monitoring, the mere use of CrackStation is legal as long as users do not attempt to crack passwords that they are not authorized to. Password Cracker is another desktop tool that can uncover hidden passwords. Since most operating systems hide passwords using round dots or asterisks for security, recovering these passwords can be difficult, especially for users who have relied on autosave features to store most passwords.

Password Cracker also supports multiple languages and is available as a free download. However, it can only crack passwords for Windows applications. Additionally, there is no support for password recovery for MS Office password-protected documents since the password encryption for MS Office is not supported by Password Cracker.

Despite the limited capabilities of Password Cracker, the software still makes the list for its relative ease of use, considering that Password Cracker is limited only to Windows applications. Like other password cracking apps on the list, Password Cracker is also safe to use, with millions of downloads and no reported instances of hash leaks. Password Cracker may be used legally, provided that users limit password cracking to owned passwords. Password Cracker is one of the simplest password cracking tools to use in the list, although its capabilities are limited.

Password Cracker is a simple, offline tool so users do not have to worry about any privacy issues or data leaks when using the program. For password cracker apps, the precise methodology differs from app to app. They all essentially create variations from a dictionary of known common passwords. The specific techniques all use a variation of the dictionary method, except the brute-force method, which relies on entering all possible combinations, starting from shorter lengths to longer ones.

However, some modes of brute-forcing still make use of a lookup table containing commonly known passwords or previously leaked passwords to speed up the password cracking process.

In theory, all passwords can be cracked but it is impractical to crack strong passwords as it takes much longer. The main factors that determine the crackability of a password are length, complexity, and uniqueness. Strong passwords use a combination of uppercase and lowercase letters, numbers, and symbols for security.

These kinds of passwords take longer to crack, as they are less likely to be found in wordlists. Strong passwords also cannot be brute-forced in a short amount of time and tend not to be used on any other website or network. While all passwords can be cracked given enough time, sufficiently complex and lengthy passwords will require so much time that cracking is realistically impossible. Certain websites allow users to input their passwords to determine how long the passwords will take to be cracked.

For long and complex passwords, the cracking process can take upwards of millions of years, which is virtually impossible for the vast majority of computers.