Tagged Questions

59 views

Brute-Force/Dictionary attack against encypted file using PBKDF2 key derivation

I have been following this very useful post by Thomas. My use case is slightly different. I am developing a mobile application which requires some sensitive data to be stored on the device in a SQLite ...
60 views

Is there an equation to calculate the number of instances of a series of characters exist in a given key space?

If I'm using 16-18 character-length passwords with 94 different possible values-per-character (lower alphas, upper alphas, numbers, and special characters), is there an equation I can use to calculate ...
29 views

How many possible symbols and punctuations in a password? [closed]

I want to compute the possible combinations of a password consists of 8 digits of: alphabetical letters (26), numbers (0-9), symbols and punctuations. In order to compute this, I have to know the ...
78 views

Given a hash, salt, charset and password length, how do you get the password without brute-forcing it?

I got that question on an exercise and I'm not sure what to answer. Without conventional brute-forcing and without a rainbow table, how could I find out the password? An improved brute-force ...
56 views

How do you overcome the problem of the salt being public and known by the attacker? [duplicate]

I believe that when adding a salt to the password you need to store the values so you can compute the hash again. But, what does happen if the attacker get the salt? How is it possible to add value ...
224 views

Could using a generated key from an online service be considered a risk?

With some colleagues we're having a debate regarding the randomkeygen.com website. I do think that there is a security risk using the generated keys of this (or any of this kind) website. Why ? ...
55 views

What is the best way to generate a password/pin like string using brute force method? [closed]

I have a string of 7 characters. I'm supposed to generate all the combinations. But some combinations are more likely than others, I would like the more likely ones to be generated first. If I ...
610 views

Hydra bruteforce is giving wrong passwords. Can't seem to work any help? [closed]

Ok so what im actually trying to do is to bruteforce my own account on some website just to check myself . This is NOT for illegal steps or use , im trying to crack my OWN password , and im trying to ...
253 views

Can't brute force password cracking somehow be throttled?

Online articles mention the importance of a strong password and suggest that hacking tools allows bad guys to attempt millions of passwords per second. I am wondering why OSes and websites and such ...
13k views

Wordlists on Kali Linux?

I notice that in /usr/share/wordlists in Kali Linux (former Backtrack) there are some lists. Are they used to bruteforce something? Is there specific list for specific kind of attacks?
2k views

Is it possible to brute force all 8 character passwords in an offline attack?

This article states: Brute-force techniques trying every possible combination of letters, numbers, and special characters had also succeeded at cracking all passwords of eight or fewer characters. ...
9k views

How to generete dictionary for brute force attack?

I need to crack my own password. Advantage is that I know possible characters and maximum length. What I need is to create dictionary for brute force attack. Dictionary should contain all the combos ...
132 views

I've been reading suggestions to use time-consuming formulas for checking passwords from login attempts, so that repeated attacks will be slowed down. Wouldn't it suffice to just sleep a bit in the ...
2k views

What are the security implications of storing password blacklist?

I want to add a password blacklist that would prevent the 1000 most common passwords from being used in order to mitigate shallow dictionary attacks. Is there any negative implication of storing this ...
440 views

How bruteforce works code wise

I was wondering how bruteforce methods work from a code level. How does the code get access to a login page for example and insert information into the necessary fields? And is the code able to ...
445 views

What are realistic rates for brute force hashing?

I'm trying to gauge password strength assuming that the attacker has a hash of my password. Can anyone cite some realistic contemporary rates at which someone could perform various hashes? I know most ...
543 views

I am using LophtCrack on my Windows 8 OS. I was testing my password strength and the problem I am seeing it is not working. It doesn't reveal my Admin password, I've run the process for half an hour. ...
399 views

Feasibility of brute-force on online password [closed]

I am familiar with how offline brute-force attacks work. But for online accounts, assuming no social engineering, how feasible is it to brute-force attack a password? For example, is this dependent ...
680 views

Can I spoof IP addresses when attempting to brute force a login?

I am testing my website with hydra brute-force software. But accessing my apache conf remote server file, it seems that an attacker can't log-in more a limited number of times per seconds. Does hydra ...
278 views

WPA2 audit tool

For the purposes of my own research, I have a very modest budget to set up a modest WPA2 brute-forcer supported by GPU(s). I've done some homework: Brute-Force GPU Password Crackers How to setup ...
945 views

Brute-force password cracker programs which claim GPU support include John the Ripper, ighashgpu, oclHashcat, and others. oclHashcat appears one of the more popular, but I am not sure which AMD/ATI ...
312 views

Bruteforce Passphrase of Dictionary Words

Consider the all lowercase passphrase: "lazy fox haggles treaty" Assume all four words are in a dictionary of 2000. Bruteforcing word combinations, how long does it take to crack this password at ...
126 views

Could a password hash that's prone to more collisions provide better overall security?

Website security breaches seem to be a common occurrence, giving the attacker password hashes that he can conduct a brute force attack against, often given him a list of passwords that will work on ...
861 views

Avoiding Brute Force Attacks in a Web Based Login Form

My login form uses Ajax so it doesn't need to reload if the password is wrong. A PHP script process the request and creates the session if the credentials are right. My idea is to have the PHP script ...
736 views

Web & insecure HTTP - Using RSA for encrypting passwords on the client side

I used client side password hashing in my register and login project. Its purpose is to prevent passive adversaries/eavesdroppers from discovering users' plaintext passwords when HTTP requests are in ...
294 views

Use brute force to mitigate brute force

Just an idea I had, and I am sure there is a lot of material about this subject, so I am looking for a pointer as to where I can find more information. My idea is this... When storing a password in ...
2k views

How long it will take to crack a RAR password?

I wonder how long it will take to crack 16 character alphanumeric WinRAR password for a mini supercomputer. As far as I know graphic cards are preferred over CPUs to crack passwords nowadays. If we ...
489 views

I used this command to password protect a zip file on Linux : zip -P 9000 hash.zip hash.py and it creates the zip file just fine, then I wrote a program to test every possible password on it from 1 ...
8k views

Why are GPUs so good at cracking passwords?

What is it about GPUs that lets them crack passwords so quickly? It seems like the driving force behind adopting good key-derivation functions for passwords (bcrpyt, PBKDF2, scrypt) instead of ...
414 views

Pointers for john the ripper rulesets

I've been pouring over the JtR ruleset documentation and making little progress. I understand how to use it to make various permutations from a given wordlist, that's fine. However, I'm trying to ...
643 views

Password Protected Zip: if attacker had one file, can use it to decrypt all files?

Consider a folder containing the following files: (file1.txt, file2.doc, file3.pdf) all zipped and password protected, if attacker had one of these file, can use it for decrypting all without knowing ...
4k views

Cracking MS-CACHE v2 hashes using GPU

As most people here will know, Windows caches domain/AD credentials in a format known as MS-Cache v2. Obviously, these would be excellent passwords to gain during a penetration test when local access ...
503 views

Insecure to require numbers in passwords?

Earlier, I went to a site that required a number and special character, and it got me thinking – wouldn't that make the password easier to brute force? If you assume most passwords have around 12 ...
238 views

is it easier to get the original password if you have multiple hashes of it?

Most users tipically use the same password for multiple applications. Let's say all of these applications hash the password in some way. Would it be easier for an attacker to get the original password ...
279 views

Can an attacker guess my password length from a hash? [duplicate]

Possible Duplicate: Possible to detect password length from hash? Is doubling your password adds more security? Considering I do not provide him any personal information relating to it, are ...
729 views

How can I prevent users from using bad passwords in my web application?

There is a long discussion on whether it's the responsibility of the user or the system administrator to deal with the strength of the password. Obviously, the password is a very private thing, but ...
976 views

Increased security with keepass

I am using keepass for securing passwords. I have a reasonable password, but if someone got hold of the file I am sure eventually they could brute force it. I was thinking of using a key file as ...
272 views

How much added security do I really get with a longer key size?

Imagine I have a cipher which supports keys of 128, 192 or 256 bits. Suppose that there are no vulnerabilities in the cipher regardless of key length. I'm going to use it to encrypt something, and ...
430 views

Is a password easier to brute force if it contains a repeating pattern?

My question is different from this previous question: Does repeating one word to form a password result in a similar pattern in its encrypted format?. I'm specifically wondering about brute force ...
387 views

Known password length, brute force character in place?

We all know that brute forcing is a very slow process and trying all unnecessary possibilities is dumb. By knowing the password length, we can skip trying possibilities of other password lengths and ...
728 views

Can a Bitlocker To Go user pin be brute forced?

I have a external hard disk and protected a partition on it with Bitlocker To Go. I printed the recovery code but I lost it. I can't remember the user PIN either. If I could only know the first ...
14k views

Remove Password Protection from XLS Document

Similar to what is listed here, http://datapigtechnologies.com/blog/index.php/hack-into-a-protected-excel-2007-or-2010-workbook/, is there a way to remove the password from an XLS (Excel 2003) ...
411 views

How can I determine whether a website somehow protects against brute force attacks on my password? (assume I can't create an anonymous account)

After the hack of Mat Honan I studied my own laundry list of accounts I have at the numerous web sites I use. There is one fact that stands out: Many of the websites severely restrict the size and ...
313 views

Seeking advice on how to build a box to brute force hashes? [closed]

I work in a startup security firm, and I need to build a GPU-based to brute force password/hashes, which can be used to validate password strength and test hashing algorithms. I expect some high ...
393 views

Hash, encryption of file… key? Need help [closed]

So my previous question was with some help on pcap files as I am doing a security course and we have a challenge to figure out what was going on in our network. Now one of the files I retrieved is an ...
581 views

Are passwords made up from concatenating a few foreign words better than shorter random characters?

Does it make sense to insert a foreign word into a paraphrase to mitigate against brute force? For example: "pussiMeansCatInEskimo" "caballoMeansHorse" "CatIsGatto" "SalopeMeansBitch" ...
567 views

Reasonable (BruteForce) Attempts/Second Estimate?

I've read various articles on password strength and passwords vs pass phrases (including the one from XKCD and its thread here), but most of those articles seem to be focused on online passwords, and ...
795 views

Are common passwords at particular risk?

The question Should we disallow common passwords like “password” and “12345”? on User Experience immediately made me think that these common passwords were extremely dangerous not because they are ...
412 views

Are there any scientific papers or publications on GPU password cracking?
167 views

Stripping / appending characters from user password before hashing to conceal it forever?

I had this idea to permanently conceal user password by requiring minimum length then stripping certain characters. For example if the user password is secret123, the system will strip it down to ...