An attack using every possible input to attempt to produce the correct output. Typically the method of last resort when no weakness allows the use of a more restricted input set. E.g. trying all possible (or likely) passwords, in an attempt to guess the correct one.

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1
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4answers
118 views

Does it take longer to brute force a password starting with z than one starting with a?

I was wondering about the following: If someone tries to get my password with Brute Force, will a password starting with "a" guessed faster than one starting with "z" ? In this case assume the ...
-4
votes
0answers
30 views

How to set a hydra http-post-form attack for this router login site? [on hold]

I'm trying to use hydra to crack it's password but don't know how to set a http-post-form attack! It's a router login websiteit which has 8088 port open.Can't do a ssh, ftp, or http-get,only ...
4
votes
4answers
402 views

Hashing a key: less entropy than the key itself

A web API needs to store a 'key' for authentication, in much the same fashion as a password but at 128 characters. My concern is that the salted SHA1 hash for the key has less entropy than the key ...
0
votes
2answers
69 views

Showing CAPTCHA

I'd like to show a CAPTCHA to prevent brute forcing attempts, but I was thinking of showing it whenever a user fails for an invalid username/password combination after X attempts, regardless of ...
8
votes
1answer
329 views

General purpose slow/unique hash routine for dup checking of private data, without storing the data itself?

I am wondering if there is a percentage of uniqueness known to be lost with every repeat of various hash routines, like MD5, SHA1, and how that might compare with other algorithms. If theoretically I ...
1
vote
1answer
259 views

Distributed IMAP-Dictionary-Attack-Tool?

I have a client with a hacked IMAP-Account, and the attacker(s) made thousands of password-attempts, probably with a fixed set of passwords, from different IPs before they got in. After successful ...
1
vote
2answers
154 views

In what situations can a hacker try to break passwords millions of times? [duplicate]

I keep reading about situations where a hacker could "easily" brute force a password (most recent example) but I'm confused about when some has an opportunity to do this kind of thing. If it is a ...
1
vote
1answer
127 views

Cracking MD5 passwords with the same salt

How long would it take to crack passwords up to 10 letters long if you knew the hashes were MD5 with a salt (that you know)?
0
votes
2answers
96 views

How long would it take to bruteforce an AES-128 protected pdf knowing the key is 20 letter long and that the charset is A-Z,0-9?

The question says everything, knowing that a pdf is protected using standard Adobe password encryption that comes with Acrobat Pro (which as far as i know is AES 128) how much would it take to ...
1
vote
2answers
63 views

Are repeating random patterns weaker than non repeating random patterns?

Which would be harder to crack: a password comprising of n characters randomly selected or a password comprising of x randomly selected characters repeated m times so that m*x=n. For example: ...
2
votes
2answers
4k 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. ...
0
votes
1answer
195 views

Cracking a web form based logon with hydra [closed]

How do I have to use hydra on a web form? What I have done so far: I already successfully used hydra on a folder with an HTTP authentication: http://localhost/test/authtest/ with user admin and ...
3
votes
3answers
81 views

Is login limiting still needed if we employ multi-factor authentication?

The status quo is that most online websites limit login attempts per IP address, or even per account since some attackers possess huge amounts of IP addresses. OWASP declares: When multi-factor ...
-2
votes
4answers
7k views

Brute-force an SSH-login that has only a 4-letter password

Suppose, you know that a certain computer is only protected by such a short password, then you could just try every possible combination easily. How would a script look like, that tries to crack that ...
1
vote
1answer
308 views

Hydra gives wrong passwords

I've been trying to use hydra (educational way) but with no success. The site method is http-post but performed by ajax (should it be a problem? I think not). After execute the command I got an output ...
2
votes
3answers
2k views

How can I generate custom brute-force dictionaries?

I have found during testing that companies often use variations of their names for critical passwords (for example Microsoft's password might be M1cr0s0f+ or m1cros0ft etc etc). So if I gave it the ...
12
votes
1answer
279 views

What's an attack's 'computational complexity'?

I'm writing a business-language report about MD5. In my search a found a paper by Yu Sasaki and Kazumaro Aoki explaining their 2123.4 pre-image attack on MD5. I know that it has something to do with ...
3
votes
4answers
183 views

Ethical brute force demo on a web login when knowing the password complexity requirements

We are currently having accounts compromised at a substantially high rate. Some in the organization believe that our password complexity requirements is enough to thwart brute force attacks. I wanted ...
5
votes
3answers
12k views

Bruteforce on 10 characters length WPA2 password

I'm trying to hack my own WPA2 network for learning purposes. I have the *.cap file generated by aircrack-ng tools after a WPA handshake. I've tested by including my own password and a bunch of ...
0
votes
0answers
54 views

My server has been brute forced what now? [duplicate]

I have installed a raspberry pi for fun at home. I opened the port 22 and this morning I was concerned about someone brute forcing my server. I ran this query : cd /var/log;zgrep ssh auth*|grep ...
1
vote
3answers
104 views

Touch tone phone username and password

I just got off the phone with Fidelity, who manage the health benefits for the company where I work. Before talking to a person, I was prompted to enter my username and password on the numeric keypad: ...
17
votes
2answers
10k 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 ...
1
vote
2answers
553 views

Can you crack a Mailinator “Alternate Inbox Name?”

From their FAQ: What are "Alternate Inbox Names" ? There are 2 ways to get email into any given inbox. When you check an inbox, listed at the top is the Alternate Inbox name. Emailing that alternate ...
0
votes
1answer
54 views

Find hash-function if original and hash are given? [duplicate]

I was thinking whether or not you can find the hash function(s) used if you have the original message and the hash. So assume that no salt is used during the hashing process, just multiple hashing and ...
0
votes
1answer
119 views

How do we estimate the time taken to crack a hash using brute force techniques

A German hacker famously managed to brute force crack a 160 bit SHA1 hash with passwords between 1 to 6 digits in 49 minutes. Now keeping everything constant (hardware, cracking technique - here ...
2
votes
1answer
231 views

Hydra bruteforce and JSON

I am having problems with Hydra and a JSON payload. The login request (intercepted with Fiddler), is the following: POST http://architectureservice.test.com/api/v1/login HTTP/1.1 Host: ...
3
votes
4answers
326 views

Can I brute-force a password hash even if I don't know the hash-algorithm used?

Can I brute-force a password hash even if I don't know the underlying algorithm? For example if I get hold of a database with password hashes and the used hash algorithm is unknown, like a random ...
12
votes
4answers
489 views

How should I secure a contact form that appears on every page of a website?

My client has a small "Contact Us" form on every page of their website. They are adamant about not including CAPTCHA verification on these forms, to keep them easy to use, but I feel it is my ...
50
votes
8answers
78k views

Where can I find good dictionaries for dictionary attacks?

I’m wondering where I can find good collections of dictionaries which can be used for dictionary attacks? I've found some through Google, but I’m interested in hearing about where you get your ...
0
votes
0answers
96 views

Testing Basic Authentication with ncrack

I'm conducting some basic pen testing against a page protected with Basic Authentication. I've sucessfully tested with Medusa and Hydra but am struggling to get the syntax correct for ncrack. the ...
10
votes
2answers
7k views

Why does Hydra return 16 valid passwords when none are valid?

I've been playing around with Hydra and DVWA and I've hit a bit of a snag - Hydra responds letting me know that the first 16 passwords in my password list are correct when none of them are. I assume ...
30
votes
2answers
33k views

How to estimate the time needed to crack RSA encryption?

How to estimate the time needed to crack RSA encryption? I mean the time needed to crack Rsa encryption with key length of 1024, 2048, 3072, 4096, 5120, 6144, 5120, 7168, 8192, 9216, 10240, 11264, ...
4
votes
4answers
407 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 ...
1
vote
2answers
125 views

How to make an efficient bruteforce attack on Windows? [closed]

I've been trying to figure out a way to efficiently bruteforce on Windows, but the method I currently have isn't very efficient. I did some profiling and found out that on average it can go through ...
0
votes
0answers
200 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 ...
6
votes
1answer
194 views

Harden a server against mass SSH DoS attacks

How can a Linux server be protected against an attacker that tries to open a large number of SSH sessions (probably trying to brute force a password) that no ports remain to be able to legitimately ...
1
vote
1answer
70 views

Can Hydra crack a flash-based login?

Is it possible to brute force a flash login with hydra? If not, what is a good tool to pen test a flash login?
1
vote
1answer
89 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 ...
-3
votes
1answer
44 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 ...
21
votes
5answers
2k views

Do non-keyboard characters make my password less susceptible to brute forcing?

I can put characters in my password for which there are no keys on a keyboard. On Windows, Alt+#### (with the numpad) inserts the character for whatever code you type in. When I put this in a ...
3
votes
2answers
16k 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) ...
1
vote
3answers
24k 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?
2
votes
1answer
108 views

Better than brute-force way to find the “lowest” sha1 hash?

While pointing out a SQL injection flaw on another question, I was able to show that an arbitrary sha1 hash could be inserted into a query such that it would be taken for a real hash, and was ...
1
vote
1answer
102 views

Username Enumeration as a Threat

I have found a Username Enumeration Vulnerability through which I am able to determine whether a particular user is registered with that site. While trying to brute force, after 5 attempts it asks for ...
5
votes
3answers
2k views

What are the odds of brute-forcing an archive with 256-bit encryption?

I have a file (a stand-alone archive). I lost the password to it, but it has been encrypted using 256-bit encryption. The password is some 20-odd characters long (including non-alphanumeric ...
2
votes
1answer
102 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 ...
0
votes
2answers
78 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 ...
0
votes
1answer
42 views

Does restarting an encrypted session increase security and deter attacks?

When a user initiates a SSH connection for example, keys are exchanged and a session is established with a new "passphrase" each time. If an attacker were to attempt to brute force this connection, ...
19
votes
10answers
4k views

Best password strength checker

In XKCD #936: Short complex password, or long dictionary passphrase? Jeff claimed that password cracking with "dictionary words separated by spaces", or "a complete sentence with punctuation", or ...
10
votes
1answer
11k views

Brute Forcing Password to a Truecrypt-encrypted file with Partial Knowledge

A while back, I encrypted a few files with Truecrypt, and stored the password in my head. Now I need to access it again, the password isn't working. I'm sure most of it is right, but I'm off by one or ...