4 ms·

Check how fast it takes to brute force your password

19 points by linhir 18y ago

henning 18y ago
The most important passwords I have are the ones for online banking and the like where you certainly aren't going to be doing bloody 25 billion attempts an hour.
- jyothi 18y ago
  Exactly. After 3 attempts most high security sites block you out and others introduce a captcha (which though crackable through crackable will introduce a delay). Any site is going to take note (or go down) of 25 billion hits/hr that too on a single account (does total traffic/hour on a site like google.com sum to this? ) The time taken is only to generate the permutations, not to crack a password.
  - samuel 18y ago
    The assumption is that you have access to the hashed version of the password. That's not so hard to get from some sites. I have retrieved user-password pairs using very simple SQL Injection in some e-commerce sites(not any the big ones, of course). The numbers give make no sense, because doesn't state which hash is using, and the difference may be huge: ~/john-1.7.2/run$ ./john --test Benchmarking: Traditional DES [128/128 BS SSE2]... DONE Many salts: 906828 c/s real, 908646 c/s virtual Only one salt: 805504 c/s real, 805504 c/s virtual Benchmarking: BSDI DES (x725) [128/128 BS SSE2]... DONE Many salts: 31271 c/s real, 31334 c/s virtual Only one salt: 30617 c/s real, 30617 c/s virtual Benchmarking: FreeBSD MD5 [32/32]... DONE Raw: 8617 c/s real, 8652 c/s virtual Benchmarking: OpenBSD Blowfish (x32) [32/32]... DONE Raw: 415 c/s real, 416 c/s virtual Benchmarking: Kerberos AFS DES [48/64 4K MMX]... DONE Short: 186368 c/s real, 186741 c/s virtual Long: 528588 c/s real, 531779 c/s virtual Benchmarking: NT LM DES [128/128 BS SSE2]... DONE Raw: 6575K c/s real, 6588K c/s virtual Which I find unbelieveable is that lots of web applications use simple MD5-passwords(not the FreeBSD MD5 based version but just MD5 hashes) without even using salts, which makes them almost instantly crackable using Rainbow tables.
    - henning 18y ago
      If you can get access to the hashed password, that's a major breach in of itself. It's almost comparable in my mind to saying, if you get physical access to the machine you can do exploits X, Y, and Z. Well, yeah, if you can get that far, you've pretty much won.
unalone 18y ago
Wow! I was surprised. I thought my password would be much easier to crack. As it turns out, I'm safe for the next 20 days or so.
- pavelludiq 18y ago
  20 days? My password is safe for the next 1,688.24 days.
  - Retric 18y ago
    Cool, what is it?
    - pavelludiq 18y ago
      You have bad social engineering skills.
randomwalker 18y ago
We can do password guessing way better than brute force by generating strings using a Markov model instead of randomly. I wrote a paper on how to do this a few years ago http://www.cs.utexas.edu/~shmat/abstracts.html#pwd http://www.cs.utexas.edu/~shmat/abstracts.html#pwd Some of the techniques have since found their way into John the Ripper. (and possibly other tools; I haven't checked.) The upshot is that you can't calculate strength with a simple formula like this. At best you get an upper bound on the time needed to crack, by a few orders of magnitude.
- gopher 18y ago
  I've created wordlists from Wikipedia database dumps some time ago (http://benjamin-schweizer.de/files/wordlist-wikipedia/ http://benjamin-schweizer.de/files/wordlist-wikipedia/); they are pretty large and thus, useful for dictionary attacks. The wordlists are sorted, common words are on top of the lists. I think that there is a typical password length, so you could improve the sorting based upon a multi-dimensional rating scheme. I'd use expected password length and commonness of a word as factors. Mixing these real words with computer generated words might speed up brute force attacks. However, I'm not sure how to integrate ordered wordfiles with rainbow tables. Any ideas?
  - randomwalker 18y ago
    rainbow tables are an implementation of the time-space tradeoff concept: you are trying to search through a space so large you cannot enumerate it. if you have already enumerated it, as in a wordlist, it is not meaningful to use rainbow tables. it's not a question of how; it's not even a well-defined operation. that's great that you've made that list though.. i wanted word frequency tables for my startup which is an entirely unrelated type of project. if i hadn't found this i would have compiled it myself; thanks much :) while your list doesn't have frequencies, i guess i can use the position in the list as a proxy for frequencies. but it's not optimal. any chance you can put up a list which also has the counts?
    - gopher 18y ago
      I don't have a current dump, but if you send me an email, I can give you the script I've written to create those dumps. It prints out the counts.
jyothi 18y ago
What does "Random Alpha/Numeric" mean ? - sequence not readable ? I observed that if you mention your password has random Alpha Numeric the time taken to break jumps to thousands of days.
q1w2e3r4t5y6 18y ago
tet

19 points by linhir 18y ago

The most important passwords I have are the ones for online banking and the like where you certainly aren't going to be doing bloody 25 billion attempts an hour.

jyothi 18y ago
Exactly. After 3 attempts most high security sites block you out and others introduce a captcha (which though crackable through crackable will introduce a delay). Any site is going to take note (or go down) of 25 billion hits/hr that too on a single account (does total traffic/hour on a site like google.com sum to this? ) The time taken is only to generate the permutations, not to crack a password.
- samuel 18y ago
  The assumption is that you have access to the hashed version of the password. That's not so hard to get from some sites. I have retrieved user-password pairs using very simple SQL Injection in some e-commerce sites(not any the big ones, of course). The numbers give make no sense, because doesn't state which hash is using, and the difference may be huge: ~/john-1.7.2/run$ ./john --test Benchmarking: Traditional DES [128/128 BS SSE2]... DONE Many salts: 906828 c/s real, 908646 c/s virtual Only one salt: 805504 c/s real, 805504 c/s virtual Benchmarking: BSDI DES (x725) [128/128 BS SSE2]... DONE Many salts: 31271 c/s real, 31334 c/s virtual Only one salt: 30617 c/s real, 30617 c/s virtual Benchmarking: FreeBSD MD5 [32/32]... DONE Raw: 8617 c/s real, 8652 c/s virtual Benchmarking: OpenBSD Blowfish (x32) [32/32]... DONE Raw: 415 c/s real, 416 c/s virtual Benchmarking: Kerberos AFS DES [48/64 4K MMX]... DONE Short: 186368 c/s real, 186741 c/s virtual Long: 528588 c/s real, 531779 c/s virtual Benchmarking: NT LM DES [128/128 BS SSE2]... DONE Raw: 6575K c/s real, 6588K c/s virtual Which I find unbelieveable is that lots of web applications use simple MD5-passwords(not the FreeBSD MD5 based version but just MD5 hashes) without even using salts, which makes them almost instantly crackable using Rainbow tables.
  - henning 18y ago
    If you can get access to the hashed password, that's a major breach in of itself. It's almost comparable in my mind to saying, if you get physical access to the machine you can do exploits X, Y, and Z. Well, yeah, if you can get that far, you've pretty much won.

unalone 18y ago

Wow! I was surprised. I thought my password would be much easier to crack. As it turns out, I'm safe for the next 20 days or so.

pavelludiq 18y ago
20 days? My password is safe for the next 1,688.24 days.
- Retric 18y ago
  Cool, what is it?
  - pavelludiq 18y ago
    You have bad social engineering skills.

randomwalker 18y ago

We can do password guessing way better than brute force by generating strings using a Markov model instead of randomly. I wrote a paper on how to do this a few years ago http://www.cs.utexas.edu/~shmat/abstracts.html#pwd http://www.cs.utexas.edu/~shmat/abstracts.html#pwd Some of the techniques have since found their way into John the Ripper. (and possibly other tools; I haven't checked.) The upshot is that you can't calculate strength with a simple formula like this. At best you get an upper bound on the time needed to crack, by a few orders of magnitude.

gopher 18y ago
I've created wordlists from Wikipedia database dumps some time ago (http://benjamin-schweizer.de/files/wordlist-wikipedia/ http://benjamin-schweizer.de/files/wordlist-wikipedia/); they are pretty large and thus, useful for dictionary attacks. The wordlists are sorted, common words are on top of the lists. I think that there is a typical password length, so you could improve the sorting based upon a multi-dimensional rating scheme. I'd use expected password length and commonness of a word as factors. Mixing these real words with computer generated words might speed up brute force attacks. However, I'm not sure how to integrate ordered wordfiles with rainbow tables. Any ideas?
- randomwalker 18y ago
  rainbow tables are an implementation of the time-space tradeoff concept: you are trying to search through a space so large you cannot enumerate it. if you have already enumerated it, as in a wordlist, it is not meaningful to use rainbow tables. it's not a question of how; it's not even a well-defined operation. that's great that you've made that list though.. i wanted word frequency tables for my startup which is an entirely unrelated type of project. if i hadn't found this i would have compiled it myself; thanks much :) while your list doesn't have frequencies, i guess i can use the position in the list as a proxy for frequencies. but it's not optimal. any chance you can put up a list which also has the counts?
  - gopher 18y ago
    I don't have a current dump, but if you send me an email, I can give you the script I've written to create those dumps. It prints out the counts.

jyothi 18y ago

What does "Random Alpha/Numeric" mean ? - sequence not readable ? I observed that if you mention your password has random Alpha Numeric the time taken to break jumps to thousands of days.

q1w2e3r4t5y6 18y ago

tet