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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Can DES-based hashed password be recovered if salt is known?

Can a hashed password be recovered if the hashing is done with DES based crypt function in PHP and both the hash and salt are known by the attacker? Consider the following example: $salt = 'mysalt'; ...
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5k views

Faster methods for decrypting a TrueCrypt disk, esp. knowing the algorithms used

I encrypted (with TrueCrypt) all my hard drives and had the passwords stored in an encrypted file on my USB disk. The passwords are all (except one) 50 character randomly-generated ciphers, there's no ...
4
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3answers
184 views

Why don't sites implement a system where a wrong password causes a 3 second delay?

I am into bitcoin right now, and the password threats scare me a little... Not so much for me, because I use LastPass and generate new passwords at 20 characters and it includes symbols, upper and ...
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2answers
791 views

How can i calculate the number of possible passwords?

I have found a flaw in a site where the password reset feature resets passwords in the following format UpperCaseLetter-Number-LowerCaseLetter-Number-LowerCaseLetter-Number-UpperCaseLetter ...
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1answer
1k views

Can this be a DoS Attack?

When I'm checking my log, I found like 15k events of " PAM service(sshd) ignoring max retries; 6 > 3 " I know this might be normal, and considered as Brute-Force attack, but can it be classified as ...
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Throttling failed login attempts: exponential timeout? by IP? using a session cookie? captcha?

I'm beginning to think this is not as simple as it looks, and many "accepted" answers here and in SO have alternative answers that criticize them. Here is what I have gathered so far Most of what I ...
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3answers
2k views

Securing AES 128 encrypted ZIPs against brute force attacks

How long would it take to brute force decrypt an AES 128 encrypted zip file if the password is 8 characters long in the range of A-Z, a-z, 1-9? Does it make any difference if .NET's System.Random ...
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4answers
1k views

Brute-force heuristics used in password cracking

Existing questions on this site discuss some of the heuristics used by password cracking tools to avoid doing a completely naive brute-force search (for example, "dictionary word with number ...
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3answers
269 views

Is there any reason in particular encryption keys aren't arbitrarily large?

It's my understanding that the more bits an encryption key has, the longer it takes to break the encryption. What is the down side of having a larger encryption key or why don't we see keys of size ...
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2answers
951 views

Known Password Lengths and security considerations

Many people wil often brag about the length of their password, like "yeah nobody is ever going to crack my password cause its 22 characters long." I was thinking, if you knew the exact length of their ...
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2answers
167 views

How can you I detect low frequency brute forcing over multiple connections?

While I realize that servers can easily detect brute forcing strategies via a single I.P, it seems that servers would be vulnerable to a distributed attack from a botnet, with each computer attempting ...
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1answer
104 views

How secure is Scrypt, really?

I've been recently taking a hard look at the scrypt system for storing users' passwords. However, I'm rather worried about it's security because of things like Litecoin miners. Is scrypt secure ...
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2answers
169 views

How much faster does a GPU or FPGA crack an RSA key compared to a CPU?

Are there any significant speed up in time on cracking an RSA key (either brute-force or factoring with general number field sieve) using a GPA or FPGA compared to a CPU? If there is a speed ...
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1answer
124 views

Analyzing log files for forensics homework?

Suppose two users have done a murder at 6pm at Dunkin Donuts, I have got the hard disks on site, disk1 and disk2. How do I identify the time and order of each user's activities on the hard disks? ...
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1answer
942 views

Securing a simple webservice against brute-force with mod-security

I want to provide basic defense against brute-force attacks against a simple HTTPS web service. The web service provides a login method (let's say at http://example.org/login) which gets passed a ...
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1answer
803 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 ...
4
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1answer
410 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 ...
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1answer
495 views

Perfectly Robust Hashing Scheme, or Completely Over-Engineered?

This is going to get long, so prepare. Basis of the question is, Do all these steps improve security, or am I completely overthinking the problem? Are my assumptions/thought process valid? We all ...
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3answers
2k views

what is the fastest and cheapest way to crack this kind of hash - md5(md5($password) + salt))?

I'm looking for a program that can use any GPU (ATI\NVIDIA) and can brute force a vBulletin hash - md5(md5($password) + salt)). I have the salt and hash. the password contains the symbols - ...
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2answers
27k 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) ...
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3answers
2k views

What utilities exist to brute force a username and password?

I'm trying to persuade management to purchase two factor authentication for securing VPN and terminal server access. I've made significant progress by demoing TSGrinder, but would like to list other ...
3
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1answer
237 views

Can a Windows or Linux password be brute-forced on a public network?

I am at a hotel that has a public network. I have a Windows machine with a wired connection to it. "Network and Sharing" has network discovery on. No folders are shared except "Users", which is shared ...
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3answers
301 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 ? ...
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5answers
680 views

Is passwords with combination of different encodings super safe?

I was thinking about generating passwords with combination of English, Arabic, Chinese charac. Is this pass secure enough against brute force attacks?
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3answers
317 views

Calculate time taken to break AES key

A 256 bit AES key is required to be broken using the brute force method on a 2GHz computer. How long would it take to break the key in the best case and in the worst case situations? Assume that 1000 ...
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3answers
580 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 ...
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2answers
738 views

Can key files be brute-forced like passwords?

Let's say you use a program like Truecrypt or Keepass which allows you to have a password + key file. I understand that passwords can be brute-forced/dictionary-attacked but is the same true for key ...
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3answers
277 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 ...
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2answers
5k views

How do you bruteforce decrypt data if you don't know what you are looking for?

If I wanted to brute-force decrypt data, I would try decrypting it with a key and see if the decryption returned nonsense. If the decryption returned meaningful data (ex. something that a natural ...
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2answers
2k views

Automated URL Discovering

I built a simple server containing static files at /files/ and I'm attempting to discover them using automated tools. I'm using wfuzz to brute force on the URL but is that the only way? Is there any ...
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3answers
919 views

Why are MD5 collisions dangerous?

I understand that the MD5 algorithm isn't collision resistant, and that collisions between data of arbitrary size can be found with more efficient methods than brute-forcing. However, I have read ...
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2answers
296 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 ...
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2answers
573 views

Implementing brute force attacks on hash values in Javascript

I'm working for my bachelor thesis at the end of which I aim to implement a proof-of-concept Javascript-based hash cracker. The idea is to work like this: Users can submit a hash value along with ...
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1answer
517 views

Academic papers on GPU password cracking?

Are there any scientific papers or publications on GPU password cracking?
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2answers
115 views

How to generate a password dictionary for a specific use

I have a locked work file that I need access to. Unfortunately, the company that provided the file is no longer in existence and I can't track anyone down to help me out. The file is encrypted and ...
3
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3answers
114 views

How is truncation according to PCI DSS secure?

In section 3.3 of the PCI standard, it says that when displaying PANs, limiting visibility to the first 6 and last 4 digits of the PAN is considered secure. Doing some quick math, on a 16 digit PAN, ...
3
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1answer
387 views

Why do so many cracking attempts originate from China?

I recently put a Linux server online and it didn't take long until I had the first attempts to brute-force the SSH login. It's not that I am worried about that - I trust the security of my server. But ...
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4answers
471 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 ...
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1answer
1k views

Is using Gmail's browser-based client, more secure than using IMAP?

I never use the same password twice and my passwords are always comprised of a long, random string of letters, numbers and symbols. (with an offline password manager to store each password string) ...
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1answer
1k views

It's really that insecure to have POP3 enabled in my gmail account?

Several people are claiming that you should turn off pop3 in gmail because it allowed bruteforce attacks on the password. Doesn't Google prevent this kind of attacks? What is the truth on this ...
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1answer
26k views

How long to brute-force WPA password?

Bob has a password (for his WPA encrypted wifi) which is 8 characters, all lowercase, and not a dictionary word. Eve lives next door to Bob and wants to illegally hack his WPA. The number of ...
3
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1answer
1k views

Will using unicode chars in my password increase security? [duplicate]

Possible Duplicate: Do non-keyboard characters make my password less susceptible to brute forcing? Bruteforce tries cracking the hash with every possible combination of letters. Then, If ...
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2answers
1k views

Failed RDP brute force attack from Microsoft IP address?

I use RDPGuard on my webserver. I have noticed that it blocked an IP address which seemed to originate from a Microsoft registered IP address: Process Information: Caller Process ID: 0xf78 Caller ...
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3answers
426 views

How to optimize compressed file cracking?

I'm currently doing research on cracking encrypted, compressed files (specifically: uif, zip, 7z, dmg). Looking at all the utilities out there, it seems the time it takes to crack something is ...
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2answers
52 views

Calculating the time required to brute force a random code

Say we have amount random entry codes of length characters from an alphabet of size alphabet. The number of possible codes is then easily calculated as keyspace = alphabet ^ length. Now take an ...
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1answer
974 views

How resistant is the iPhone encryption against brute-force attacks?

I just read the following paragraph in an article from the New York Times about Apple encrypting iPhones by default): Breaking the code, according to an Apple technical guide, could take “more ...
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2answers
2k views

Closely spaced failed logins in auth.log

I have a raspberry-pi (running GNU/Linux) and I recently allowed my router to forward port 22 (ssh) to the raspberry-pi so that I could log in while away from home. I then noticed a bunch of ...
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4answers
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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 ...
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1answer
337 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 ...
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2answers
23k views

How to setup GPU for Cracking WPA/WPA2?

I have a Dell N5110 15R Laptop that I'm planning to use for GPU based cracking of WPA/WPA2 passwords. The thing is, I'm not a really big fan of password dictionaries and rainbow tables, I'd rather ...