Brute force cracking: Brute force (also known as brute force cracking) is a trial and error method used by application programs to decode encrypted data such as. Just adapt the program to work only on a part of the key space (given by parameter), and then call it several times in parallel, e.g. Once for keys starting with A-M, once for N-Z, once for a-m, once for n-z and once for 0-9. Of course, use same-size sections and just that many times as you have cores (or one less so you can still use your computer). This means they'll have a chance of 1 in 36^10 (1 in 062976) of actually entering a working key. This effectively eliminates brute-force methods. And if you make the program pause for about two seconds (or even better, take longer for each attempt), brute-force attempts become pathetic jokes. The more people you have running the script at once the faster it is to crack the code; a team of 4 can break the code in roughly 20 mins. This is only really worth it if you are trying to open metal doors or vaults as it saves you a fair amount of resources.

Cory Doctorow recently linked to this fascinating email from Jon Callas, the CTO of PGP corporation. In it, Jon describes the impossibility of brute force attacks on modern cryptography:

Simple HS256 JWT token brute force cracker. Contribute to lmammino/jwt-cracker development by creating an account on GitHub. Brute force attackers guess passwords, passphrases, and private keys in an attempt to eventually get the right answer and crack the security of a system. They systematically guess every combination. For example, if they were guessing telephone numbers in the US.

Modern cryptographic systems are essentially unbreakable, particularly if an adversary is restricted to intercepts. We have argued for, designed, and built systems with 128 bits of security precisely because they are essentially unbreakable. It is very easy to underestimate the power of exponentials. 2^128 is a very big number. Burt Kaliski first came up with this characterization, and if he had a nickel for every time I tell it, he could buy a latte or three.

Imagine a computer that is the size of a grain of sand that can test keys against some encrypted data. Also imagine that it can test a key in the amount of time it takes light to cross it. Then consider a cluster of these computers, so many that if you covered the earth with them, they would cover the whole planet to the height of 1 meter. The cluster of computers would crack a 128-bit key on average in 1,000 years.

If you want to brute-force a key, it literally takes a planet-ful of computers. And of course, there are always 256-bit keys, if you worry about the possibility that government has a spare planet that they want to devote to key-cracking.

Each additonal bit doubles the number of keys you have to test in a brute force attack, so by the time you get to 128 or 256 bits, you have a staggeringly large number of potential keys to test. The classic illustration of this exponential growth is the fable of the mathematician, the king, and the chess board:

There is an old Persian legend about a clever courtier who presented a beautifulchessboard to his king and requested that the king give him in return 1 grain of rice for the first square on the board, 2 grains of rice for the second square, 4 grains for the third, and so forth. The king readily agreed and ordered rice to be brought from his stores. By the fortieth square a million million rice grains had to be brought from the storerooms. The king's entire rice supply was exhausted long before he reached the sixty-fourth square. Exponential increase is deceptive because it generates immense numbers very quickly.

By the time you get to that 32nd chessboard square, you're facing a very large number indeed.

However, 2^32 isn't necessarily a very large set of keys when you're performing a brute force attack with a worldwide distributed network of computers. Such as the RC5 distributed computing project. Here's what they've done so far:

• a 56-bit key was cracked in 250 days.
• a 64-bit key was cracked in 1,757 days.
• a 72-bit key is still being cracked; 1,316 days so far with 379,906 days remaining.

The earliest 56-bit challenge, which ended in 1997, tested keys at a rate of 1.6 million per second. The ongoing 72-bit challenge is currently testing keys at the rate of 139.2 million per second. We're testing keys 88 times faster than we were 10 years ago, through natural increases in computing power and additional computers added to the distributed computing network.

And yet the RC5-72 project still has 1,040 years to go before they test the entire keyspace. Remember, that's for a lousy 72-bit key! If we want to double the amount of time the brute force attack will take, all we need to do is tack on one teeny, tiny little bit to our key. 73-bit key? 2,080 years. 74-bit key? 4,160 years.

It's painfully clear that a brute force attack on even a 128 bit key is a fool's errand. Even if you're using a planet covered with computers that crack keys at the speed of light.

If you're a smart attacker, you already know that brute force key attacks are strictly for dummies with no grasp of math or time. There are so many other vulnerabilities that are much, much easier to attack:

• Rootkits
• Social engineering
• Keyloggers
• Obtain the private key file and attack the password on it

Of course, beyond ruling out brute force attacks, I'm barely scratching the surface here. Jon Callas' Black Hat conference presentation Hacking PGP (pdf) goes into much more detail, if you're interested.

by hash3liZer . 09 September 2019

WPA/WPA2 cracking has been a focus point in the community since many years. And we have tools to aim that focus like aircrack and hashcat. Some new advancements have been made to aid that focus in the past couple of years.

So, Cracking WPA/WPA2 has been quite a topic now. In this tutorial, we are going to cover one of the infamous tools 'hashcat' for cracking WPA/WPA2.

Hashcat which is primarily built for brute forcing different kind of hashes using different kind of attack vectors, supports cracking for two of badly known WPA/WPA2 attacks. Well, for the list of available hashes, you can check the hash modes section in the manual:

In previous, you might have seen or even worked with aircrack to crack WPA/WPA2 by capturing a 4-way handshake. But that was not anywhere close to how perfect could this tool be for the purpose. Besides, hashcat is a GPU + CPU maintained tool which makes it a lot more faster.

How To Brute Force Program Serial Keyboard

In short, if you own a GPU, always go for hashcat or else you could use an online service or buy out some GPU based server on Internet.

We will cover up with two famous WPA/WPA attacks, precisely the cracking of MIC (4-way handshake) and PMKID (1st packet/handshake). So, let's begin.

Installation

Hashcat is built to work on Windows, Linux and as well as on Mac. You can go to hashcat.net and download the binaries and follow the instruction for your operating system. What we are going to do here is clone a fresh copy of hashcat from github and manually install it on a debain based linux.

Preferably, you should use Kali Or Parrot but a similar distro like Ubuntu will work as well.

Update Your Repo's and install the following dependencies:

Clone hashcat from github and move to directory:

Finally, compile the binaries and we are all set with hashcat.

You may try printing the help manual for hashcat to check whether you have it installed perfectly or not.

Hcxtools:

Now, let's clone and compile hcxtools from github. It is basically a set of various files to convert and generate another version of the supplied input. We will use it to convert the captured traffic into a format understandable by hashcat.

First, clone the repo and move the hcxtools directory:

And finally, run the make command to compile binaries and make necessary changes in path.

After having the requirements installed, we move to the cracking part. Below this, i am dividing the tutorial into two parts, first we will crack the WPA/WPA2 using MIC aka 4-way handshake. While in second, i'll do cracking using PMKID.

PART A

Let's clear how the MIC cracking actually works. So, in this case, we need a valid 4-way handshake. The handshake consists of many keys that are interchanged during the authentication between the client and access point.

These independent keys are used to generate a common key named 'Message Integrity Code (MIC)'. This generated MIC is used to validate the given password by cracker.

/kalaham-tamil-font-free-download.html. The algorithm to compute MIC is quite long and tricky and i've have covered that up in another tutorial here. So, let the cracking begin.

STEP 1

Conversion to hccapx format

Supposing you already have a captured 4-way handshake using some tool like airodump, but you still need the proper format to supply it to hashcat. To convert it to a proper format (hccapx), you need another tool.

There are already some online services that you may use: https://hashcat.net/cap2hccapx/

But still in case you are wondering to do it locally, clone the hashcat-utils repo from github:

Finally, compile the binaries. After compiling, you will have the binaries under same directory. The binary file that we need is cap2hccapx.bin. To make sure, you have it correctly compiled, try to execute the file, it will throw you back the syntax:

So, after having it installed, use the below given syntax to convert the .cap file to .hccapx hashcat capture format.

So, this will generate a file by the name 'hashfile.hccapx', which is what we are going to use with hashcat. Now, you may move to whatever directory you want, since will be cracking the final format now.

STEP 2

Cracking WPA/WPA2 (handshake) with hashcat

With hashcat, there is a possibily of various attack vectors. We could do a straight dictionary attack, brute-force attack, combinator attack or even masks attack, i.e. making rules to find various possibilities of trying different characters at different positions.

Anyhow, let's study the actual cracking of WPA/WPA2 handshake with hashcat.

Dictionary Attack:

As named, you need a wordlist for it to work. Considering you have solid list of possible wifi passphrases, or if not, you can download the famous ones: https://www.wirelesshack.org/wpa-wpa2-word-list-dictionaries.html

Launch the following command for dictionary attack:

• -a: specifies cracking mode. In our case it's dictionary mode and '/path/to/dict.txt' is complete path to the wordlist.
• -m: hash mode. Specifies what type of hash we are dealing with.

In Case You Receive issues regarding Intel CPU or 'No devices found/left', use --force argument to force the usage of your device.

Brute-Force Attack:

The Brute-force is different than the dictionary attack. Here, we try to replace every character at every possible position in a specified length from a given charset. For example, in a string of length 8, we can try every character from A-Z at every postion in this string.

That's how brute-forcing works and hence very time-consuming. Launch the following command to start your first attempt for brute-forcing:

• -a: specifies the cracking mode and here the value 3 indicates, we are running a brute-force attack.
• ?d?d?d?d?d?d?d?d: is the brute-forcing rule here. It specifies what kind of values to check, where to replace and also assumes how much time could it take to crack the key.

How To Brute Force Program Serial Key Generator

The above mask i.e. '?d?d?d?d?d?d?d?d' states to check a string of length 8 with a digit at every position. You can study about mask attack here: Hashcat Mask Attack.

Watch dogs 2 download for ppsspp. PART B

Part A was about the handshake cracking. Whilst now, we are going to crack PMKID with hashcat. The PMKID is located in the 1st packet of 4-way handshake and hence it's kind of more useful because we don't need a complete handshake.

The algorithm to compute PMKID is given which is quite easier than that of MIC.

Let the cracking begin for PMKID.

STEP 1

Getting the PMKID hash

The first thing to proceed with PMKID cracking is the pmkid hash. To generate it we need the first packet of the 4-way handshake. Considering you already have that, we will extract the hash from the captured file.

If you are not aware of how to capture the first packet of 4-way handshake, follow this tutorial.

Let's do the conversion. Execute the below command

This will generate a file by the name pmkid.hash that we will use with hashcat to do the cracking.

STEP 2

Cracking WPA/WPA2 (PMKID) with hashcat

Just like previous part, we will apply the same rules here except for the hash mode argument. The hash mode value for PMKID cracking is 16800.

Dictionary Attack:

As per syntax we have back in the PART A section for dictionary attack, we will use that very same syntax except for the -m argument which defines what kind of hash we want to crack. We will be cracking pmkid (16800) this time.

While this would crack the key by looping through each line given in the wordlist.

How To Brute Force Program Serial Keygen

Brute-Force Attack:

How To Brute Force Program Serial Keypad

We will do same here as last section i.e. providing a mask to crack the hash. This time, just to show how powerful these masks could be, i'll use a different one. So, execute the command for brute-force attack:

The above mask will create combinations of string of length 8 with every alphabet at every possible position. And this sounds like a huge combination that may take a lot of time to complete. To make the attack more faster, we can use the GPU.

CPU/GPU

Now, getting into CPU/GPU thing, we just need to know that GPU is a lot more faster than CPU and hashcat have the ability to do cracking on your GPU. Hashcat has following three device modes which can be changed via -d argument:

• 1: CPU which is by default, selected.
• 2: GPU
• 3: DSP, Co-processor.

You can use one of these devices according to what's more suitable for you. For example,

To accomplish PMKID attack on GPU. That's it, i.e. cracking WPA/WPA2 via hashcat.

Conclusion

The conclusion that can be drawn out of all above is that hashcat is not just limited for a number of hashes, infact it's applicable to a wide range of hashes and other possibilities including mixes and concatenated strings. We learned to crack WPA/WPA2 using hashcat.

Besides, hashcat is known of it's power, stability and speed by operating on GPU. It also gives us the possibility of mask attack which let us play with possibilities of testing thousand of thousands strings against the hash.

For Any Questions, Queries, mistakes, you can comment down.