Specific to the security of passwords: hashing, entropy, cracking, resets, lockouts, etc.

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12
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3answers
4k views

How can I prevent someone from accessing a Windows XP system via boot disk?

Apparently a computer system protected by a a login password, e.g. Windows XP, can be easily hacked by someone with physical access to it using methods like this one: http://www.raymond.cc/blog/...
2
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6answers
756 views

Why does the password field not show the entered text?

Why does the password field not show the entered text? When we enter password it shows ... or '*'. What are the security advantages of this?
0
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1answer
204 views

How can I prevent my son accessing my PC? [duplicate]

Possible Duplicate: How can I prevent my kids from bypassing my computer restrictions based on Windows Vista? My 14 year-old son is using a Ctrl+Alt+Del procedure to get into my computer even ...
4
votes
3answers
662 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 ...
15
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2answers
2k views

Are there some good papers (or discussions) on using Markov chains or Hidden Markov Models for password auditing/cracking?

As a programmer and language enthusiast I've been very interested in Markov chains for some time. Considering the influence of natural language on password and passphrase selection (by humans of ...
4
votes
4answers
1k views

Can public keys be a security risk when performing password-less SSH logins?

Some companies use monitoring software such as nagios or icinga. In order to perform checks on the servers, they often need password-less SSH logins. The servers being checked put the public key of ...
5
votes
3answers
448 views

Are there any regulations against financial companies storing passwords in plaintext?

A bank that I use stores my password in cleartext or perhaps using reverisible encryption, which is just as bad. I know this because when you click "Forgot your password?" (or similar) link, it ...
1
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1answer
627 views

Securely tell the user his password in new WHM/Cpanel account creation?

I understand it's not safe to send passwords via email but when accounts are created via WHM/Cpanel, I have to let the user know what password I created for them. How can I relay the password safely?
1
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3answers
436 views

Logic for generating Strong Password?

I try to encrypt password using MD5 but there are decoders for MD5. So I'm worried about encryption of password for big website. Is there any logical suggestion or step function to generate strong ...
2
votes
1answer
657 views

How can passwords be stolen from Yahoo?

I always understood that servers don't actually store user passwords. Instead, they store hashes of passwords and then they validate the user input by applying the hash function, then compare the ...
4
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4answers
567 views

Is there any explanation (other than storing plaintext) for case-insensitive passwords?

I've come across a few organisations stating that passwords are case-insensitive. Obviously this is ridiculous, and a gigantic red flag from a security point of view. Is there any explanation for why ...
5
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7answers
2k views

What is the best way to securely keep clear passwords?

I'm working on a web project that will connect to a database. For that, I will have to store the login/password of that database user in clear (encrypted in a symmetrical way) in order to be able to ...
9
votes
1answer
1k views

Bcrypt as a key derivation function?

I read a lot of entries at stack exchange about bcrypt and why it is supposed to be better than PBKDF2 in terms of password storage. I'm asking now if bcrypt is better than PBKDF2 in terms of key ...
33
votes
7answers
13k views

How can crackers reconstruct 200k salted password hashes so fast?

I'm researching for a small talk about websecurity and I found one article about the formspring hack, which made me curious. They claim to have used SHA-256 + salt We were able to immediately fix ...
4
votes
4answers
545 views

Is it secure to use similar password over different accounts?

I have a strong password which is a long, unfamiliar word phrase. I would like make other account use a password with similar level of complexity but I don't like to remember so many password over ...
1
vote
2answers
432 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 ...
3
votes
3answers
297 views

When changing a password, does it have to be completely different?

When changing a password how important is it to have a significantly different one? For example is it bad to reverse the sequencing of the old password to make a new one or change a few numbers?
1
vote
2answers
175 views

is it appropriate to set restrictions on a user's password? [duplicate]

Possible Duplicate: XKCD #936: Short complex password, or long dictionary passphrase? Im developing a website and am curious as to the current trends in the nature of passwords. Is it good to ...
5
votes
3answers
747 views

Trying to understand password hashing

I am trying to get a grasp of password hashing. Back in the days it seemed so simple, just MD5(password + salt) and you are done. Then md5 was proven to have collisions so people started moving to ...
2
votes
4answers
545 views

If the attacker knows part of the password but not the length, does that help him in any way?

The idea behind this is that if knowing part of the password and not the length is useless, "passwords" can be easily stored in cleartext or paper since you would just add your own n characters ...
0
votes
0answers
244 views

What is the most secure way to recover password online? [duplicate]

Possible Duplicate: Can anyone provide references for implementing web application self password reset mechanisms properly? I have website which sends generated password to any person who ...
28
votes
4answers
7k views

Why is using salt more secure?

Storing the hash of users' passwords, e.g. in a database, is insecure since human passwords are vulnerable to dictionary attacks. Everyone suggests that this is mitigated via the use of salts, but the ...
40
votes
7answers
3k views

“Real” Salt and “Fake” Salt

During a Q&A period at DEFCON this year, one member of the audience mentioned that we're using "fake salt" when concatenating a random value and a password before hashing. He defined "real salt" ...
9
votes
1answer
999 views

Would it make sense to use Bcrypt and PBKDF2 together?

I've read various opinions about whether Bcrypt or PDBKF2 is a better key derivation hashing method. The answer seems to depend on a lot of complicated factors that are not easy to analyze. Would ...
15
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3answers
2k views

What is a good enough salt for a SaltedHash?

Since I'm hashing all passwords with each their own salt, is there a benefit to the salt being really random, or would an incremental counter or a guid be good enough? Also, is there a benefit of ...
0
votes
1answer
656 views

website hacked and all its content erased despite the protections

i was hacked by a guy who erased everything. I spent the day to put everything in order, and i would like to find a solution for this : he erased all the files, and also changed the title for "www" in ...
7
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1answer
4k views

Does NIST really recommend PBKDF2 for password hashing?

We hesitated between BCrypt and PBKDF2 for password hashing. In many forums and blogs people say something like "In their Special Publication SP 800-132 NIST basically recommends using PBKDF2 for ...
1
vote
2answers
546 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 ...
-2
votes
3answers
300 views

Password security : complexity and length [duplicate]

Possible Duplicate: XKCD #936: Short complex password, or long dictionary passphrase? I've read that there is many solutions available to crack passwords. Reading these tips, I can understand ...
-1
votes
1answer
659 views

What encryption hash function I should use for password securing? [duplicate]

Possible Duplicate: How to securely hash passwords? What is the best encryption algorithm? MD5, SHA1, SHA2 or maybe something else? Can you explain me why?
1
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3answers
308 views

Does this kind of hashing exist?

Let's say you have two user defined strings, X, Y and you want to hash them into the hash Z. That is what most websites would do, X is the user's password and Y is the salt. It takes a lot of time to ...
11
votes
4answers
718 views

How should I tell an organisation that they are vulnerable when I wasn't given permission to check?

I was recently at a village hall (in the UK), some distance from where I live, for a party. I noticed that they had unsecured wi-fi with an SSID of NETGEAR. I assumed it was free wi-fi for users of ...
7
votes
3answers
515 views

Is it advisable to have a web browser remember login credentials?

I have a really long random password for my cellphone account and have it written down in a safe place. I only use it once a month and am considering having my browser remember it. Would there be any ...
1
vote
4answers
527 views

Are there vunerabilities with this authentication mechanism?

I am trying to come up with a way to implement token-based authentication for a REST API without the need for SSL. The goal here is to avoid sending any sensitive information across the wire. I was ...
0
votes
2answers
2k views

Long Passwords: How are they more secure? [duplicate]

Possible Duplicate: XKCD #936: Short complex password, or long dictionary passphrase? How are long passwords more secure? The only situation in which I can accept long passwords are more ...
7
votes
2answers
6k views

How expensive is it to guess a 15 character password, and should I be worried?

I'm currently using AES encryption (at home) on GNU/Linux (one of LUKS AES-256 variants with xts) and on Windows 7 (Truecrypt) with a 15 characters password (alphanumeric lowercase only plus _). ...
5
votes
5answers
2k views

What password cracking software is commonly used?

I am curious to know how secure my passwords are. What password cracking software is commonly used? Preferably open source. EDIT: I am actually looking to crack my passwords used on services I don'...
47
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2answers
5k views

Pre-hash password before applying bcrypt to avoid restricting password length

Good practice is not to unnecessarily restrict password length, so that appropriately-long passphrases (perhaps 35-45 chars for 6/7 dicewords) can be used. (See e.g. Should I have a maximum password ...
5
votes
4answers
3k views

Send new password by email is bad practice but what to do if user forgot his password?

According to http://plaintextoffenders.com/post/7006690494/whats-so-wrong-about-sending-a-new-password-in it's bad so what to do ? Just ask him to set a new one ?
2
votes
3answers
2k views

Why would you do a password audit

I was thinking last night after reading an article about pen testing and security audits, why would you get a list of all the passwords for the company you are auditing and put them through a piece of ...
3
votes
3answers
597 views

What pros and cons are there to a one-time random salt between client and server?

In researching on best practices in hashing passwords using a salt I came across a presentation on slideshare. The approach outlined is as follows Client requests login page Server-side code ...
7
votes
4answers
1k views

Password hashes should run md5 thousands of time: really?

I skimmed through How Companies Can Beef Up Password Security and I thought that several assertions were completely wrong, in particular: Cryptographic hash (like md5) with salt are bad. It isn't ...
5
votes
5answers
420 views

Tool to grab sensitive information from command lines [closed]

Of the information entered on the command line (command name and arguments) have to be considered public (everyone can access it using commands like ps). Is there a known tool to automate this kind ...
24
votes
6answers
2k views

Online password managers

Can online password managers be used for storing and managing passwords? I mean from the security point of view. I understand that those systems can be different and some deserves more trust than the ...
0
votes
1answer
1k views

What's the idea behind requiring users to change password periodically? [duplicate]

Possible Duplicate: How does changing your password every 90 days increase security? Some sites require users to change their password every x days. For example, at least 3 online banking ...
4
votes
1answer
972 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 ...
8
votes
3answers
805 views

An alternative to traditional passwords: is there some merit to this idea?

If you've got a website aimed at people that are not neccessarily technically proficient, letting new users choose their own password isn't very secure because of the simple fact that a lot of people ...
5
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1answer
3k views

Which cross-platform password managers support encryption using a hardware token?

I am looking for a really secure password manager and I really like the fact that Password Safe supports encryption/decryption using a Yubikey programmed in challenge-response mode. Read more here: ...
31
votes
8answers
5k views

Is it safe to use leakedin.org?

leakedin.org claims to offer a service checking if your LinkedIn password has been stolen and whether it has been cracked. The website claims that it's pure Javascript, that is your password won't ...
3
votes
3answers
15k views

Database field type for password storage?

In the past I used varchar(255) for storing hashed passwords (no salt). Is this still enough? Or are longer fields required?