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Pwned Passwords in Practice: Real World Examples of Blocking the Worst Passwords

190 points by robin_reala 8y ago

willvarfar 8y ago
The Okta chrome extension mentioned in the article seems very cool and useful. But how do we trust the Okta chrome extension not to post all credentials to the developer? Even if its doing nothing shady now, in some future update?
- amdavidson 8y ago
  With that security model, how do you trust any extension at all? At least with this one, you can audit the source code and build it for yourself[0] 0: https://github.com/OktaSecurityLabs/passprotect-chrome https://github.com/OktaSecurityLabs/passprotect-chrome
  - willvarfar 8y ago
    I once made a webpage where HNers drag-dropped their entire iphone backups. It got me thinking. http://markolson.github.io/js-sqlite-map-thing/ http://markolson.github.io/js-sqlite-map-thing/
    - crtasm 8y ago
      It decrypts their backup locally? The link to code in the footer just refreshes the page.
      - willvarfar 8y ago
        It parses an unencrypted sqlite db in their backups in client-side javascript. The whole thing is client-side javascript. But... if we'd wanted to be nasty we could have sent everything to servers we controlled. The src link stopped working when gitlab.io arrived I think https://github.com/markolson/js-sqlite-map-thing/ https://github.com/markolson/js-sqlite-map-thing/
    - ReverseCold 8y ago
      Whenever there are tools like this I usually just visit the site then unplug my ethernet/disconnect from WiFi. If it's actually client side JS it will work. I'm pretty sure this is safe, but if there's a way to defer sending an HTTP request to after the page being closed...
      - phyzome 8y ago
        If you do it from a private browsing window, maybe that would be fine. Maybe. (Otherwise the page could exfiltrate information via localstorage or something.)
      - willvarfar 8y ago
        You'd just motivate me to use client-side storage if the upload failed. Don't dare come back to the page when online! :)
programbreeding 8y ago
I'm a huge fan of Troy Hunt and HIBP, but reading this I assumed it was basically an advertisement to get people to sign up for the Pwned Passwords API -- I admit I didn't make it down to the "And Finally..." section where he explains that it's free because there were a bunch of pictures at the bottom and I stopped reading. But reading through the API docs [0] it shows that API has no rate limit. Impressive. [0] https://haveibeenpwned.com/API/v2#SearchingPwnedPasswordsByPassword https://haveibeenpwned.com/API/v2#SearchingPwnedPasswordsByP...
- pit2 8y ago
  Even if he's not charging for the service, I am pretty sure he's getting more consultancy work from these "PR" (notice the quotes) posts. Even the timing on which he releases them makes sense in a way to prevent people from getting too tired of this service. Not saying is a bad thing but don't assume something is for pure altruism because not many things are.
  - Arnt 8y ago
    Have you ever been paid to do work that you really want to happen? Been paid to improve the world in a small, but significant way? It's a lovely feeling.
    - PietdeVries 8y ago
      But what is the value-add of this service? Complex passwords are quite useful if the server gets hacked and someone walks away with the (salted) password hashes. Against brute-forcing passwords at the login screen of an application they don't add much value, other than making it the user quite hard to remember what the password for this particular site could be... Theoretically, if you block a user ID after say 5 or so invalid logins, almost any bad password from the Have I been P0wned list will prevent you from being hacked. The chance that you pick exactly that password from the 1-million or so list is quite minimal. So with that in mind, wouldn't this service be something for website owners that don't know how to properly secure the information they control?
qrbLPHiKpiux 8y ago
Great in theory, I don’t think it will play out good because of the average computer user. Ask any help desk employee.
- teknopaul 8y ago
  Word. Password security should be proportional to chance of a dictionary attack * risk of a successful attack. Mozilla want a 12 character passwords to file a bug report when they really should publish an email address an anonymous html form and say please.
  - robin_reala 8y ago
    They do? Help / Submit Feedback / Firefox makes me sad, then fill in the form.
  - kikoreis 8y ago
    I know what you are feeling, but there's a balance to making bug filing easy. For a large visible project, make it easy and the statistical noise drowns everything out.
mkirklions 8y ago
The only thing I had a hard time understanding- OP really cares about his privacy/security/password, but then he uses a secondary system to store it? Is this the best way to do this? Break into the secondary system and everything is available. Keyloggers, eyes, stolen computers, all have the possibility of everything available. I considered other solutions like written + put in a lock box in a bank, but thats really inaccessable.
- rjacksonm1 8y ago
  It is the best way to do it for the average user. Modern password management services are incredibly secure, with client-side encryption of your secrets, among other protective mechanisms (to guard against keyloggers, stolen computers, ...) There is still a risk, because you're trusting third-party software (which in some cases is closed-source – including 1Password), but for most people that is a much lower risk profile than if they were managing passwords themselves. For specifics on 1password's security, check out https://1password.com/security/ https://1password.com/security/
  - willvarfar 8y ago
    > Modern password management services are incredibly secure There lots of password managers that have had gaping vulnerabilities. From memory I'm sure I've seen LastPass vulnerabilities top HN just a while ago... yeah probably this one: https://www.bankinfosecurity.com/lastpass-patches-password-manager-vulnerability-a-9299 https://www.bankinfosecurity.com/lastpass-patches-password-m...
- SCdF 8y ago
  It does sound a bit silly, but the alternative is to keep them in your brain, and AFAICT it's impossible to do that these days. I have hundreds of accounts in my password manager, I couldn't possibly remember secure passwords for all of them. FWIW I'm not a fan of keeping them in some cloud service dedicated for storing passwords (1PW's subscription offering, lastpass) because if someone is going to break into servers and steal passwords it's going to be from those fine people. A middle ground is to use something like KeePass, where the encrypted password file is stored where you want it to be stored (ie your hard drive), where you can manage how you want to distribute that file between places you need it.
sethgecko 8y ago
I wrote this small python function to check if a password is part of a breach by transmitting only the first 5 digits of it's hash: https://gist.github.com/mcdallas/d94ecd8b34a6bf57a162a7af0ce2a664 https://gist.github.com/mcdallas/d94ecd8b34a6bf57a162a7af0ce...
- rahimnathwani 8y ago
  Your code uses the first 5 digits of the hex digest of the SHA1. This 5-digit hex number has roughly 1 million combinations. That seems way too low. For context: If you take just dictionary words from the world's 5 most popular languages, you'd have more than 0.5 million words.
  - sethgecko 8y ago
    This is from the API docs, you are not allowed to pick the number of digits. https://haveibeenpwned.com/API/v2#SearchingPwnedPasswordsByRange https://haveibeenpwned.com/API/v2#SearchingPwnedPasswordsByR...
    - rahimnathwani 8y ago
      Oh I see, so you send only the first 5 digits, but you then get back ~16,730 digits (478 * (40-5)) and search those for your full hash.
  - qop 8y ago
    So what if you then took positives from 5dig hash matches and searched then through 7dig hash matches? Like a sieve? With a good cache, thatd save some bandwidth. Maybe that's wishful thinking. I can't imagine checking new passwords more than a few dozen times per second at the most. Bigger sites probably just write their own password integrity tools.
    - mrybczyn 8y ago
      I applaud your optimism! Most places just enforce byzantine password requirements, 13 digits, must have ~, uppercase and a palindrome prime integer in it. Obligatory password XKCD, think of the children. https://xkcd.com/936/ https://xkcd.com/936/
ransom1538 8y ago
Stupid question here. But shouldn't websites/apps simply lock the account for 5 minutes after 3 bad password attempts? -- basically ending the usefulness of bad password lists, etc etc. Do sites actually let you run limitless password attempts -- thus really find these password lists important? If your password was "foofoo", and there was a password lock after 3 attempts I don't see how you would crack it with a password file (in this lifetime).
- snowwolf 8y ago
  Because the email/password combination is already known. From a previous breach where you used the same combination. So the attacker needs exactly 1 attempt to get into your account. And with the ease of using botnets now, they can get access to a very large number of IPs to distribute the attack, so you can't reliably throttle at IP level either.
- elorant 8y ago
  I've tried that once in a site and it was a maintenance nightmare. Users kept bombarding me with emails asking to unlock their accounts. Turns out 99 times out of 100 that a username/password combo has been mistyped it's from users jerking around or not remembering the password, rather from hackers trying to brute force their entrance. Now imagine having a site with a few million accounts and 0,1% of them mistyping the password every now and then.
  - ransom1538 8y ago
    You don't have a 'forgot password' system?
  - paulpauper 8y ago
    One could set the threshold to 40 failed attempts. brute forcing requires thousands of attempts.
  - scient 8y ago
    Sounds like a case of not handling the UX of the feature properly. What you can do is either allow them to unlock the account via email, or have a time-based unlock, or both. We do 72 hours or unlock it via email.
paulpauper 8y ago
reminder: never enter your email on one of those 'have i been pwned databases' . Find a way to download the database offline and then check it.
- SmellyGeekBoy 8y ago
  I'm signed up his automated alerts whenever my email appears on a leaked password list online. I had one through just the other day, then a load of alerts that my Ubisoft account was being accessed from various places all over the world (I have no idea when/why I set up a Ubisoft account, but there you go). It's a very useful service - and free. No way am I going to manually download every single password dump that appears online and search it for my details.
  - ummonk 8y ago
    Same for my Ubisoft account last night. I've been using 1password for all my new passwords, but obviously there are still old accounts lying around with overused passwords of mine.
- forgotmypw 8y ago
  Not sure why this was voted down. By entering your email, you are providing lots of valuable data to a potential attacker: that you are active, your IP address and environment, all of which can help unlock your account on whatever service was compromised.
  - moviuro 8y ago
    Who could possibly get this info on https://haveibeenpwned.com https://haveibeenpwned.com ? Troy? I bet he doesn't even keep logs. Anyone listening to your HTTPS connections? Then you have some more serious issues. No seriously, Troy's site is awesome, and spreading FUD is not doing them any service.
    - jsmeaton 8y ago
      It’s good advice in general for most folks. For those that know of Troy and this particular site it’s fine, but the general recommendation still stands.
Animats 8y ago
they gave people the ability to check any individual password against the online Pwned Passwords service What could possibly go wrong? This works by locally hashing your password, then sending only the first 5 hex characters of the hash to the server. The server sends back all matching hashes of bad passwords it has on file. Typically this returns a few hundred hits. The local client (probably some piece of Javascript) checks the hits against the password hashes returned. If there's a match, the password is in the database of bad passwords. This supposedly protects the password if communications with the checker are intercepted. But does it? If an attacker can see those first 5 hex characters, they too can get the list of hashes of matching passwords. There are only a few hundred of them, and they're hashes, not the actual passwords. One of those is the hash of the user's password. Now they know what hashes to try. An attacker presumably has a big database of likely passwords to try. So they can create a database of hashes locally. The hashing algorithm is known to the client, after all. So now they have a few hundred passwords to try for a break-in. Try those over the next few days, and they're in. Is it really that bad, or am I misunderstanding something here?
- jxcl 8y ago
  The point of a secure password is that it _won't_ be in the list of hashes by the server. The service should prevent the user from using any of the passwords that are matched by the password database.
- 0xdeadbeefbabe 8y ago
  That doesn't sound so bad. Real attackers probably try something easier first.
- jandrese 8y ago
  The point is if you get a match you deny that password and make the user try again. So this would only give you a list of 100 or so passwords that it couldn't be. Not even a drop in the bucket of the namespace you need to search.
- drexlspivey 8y ago
  > One of those is the hash of the user's password. Why? Your hash might not be in the list. There are 16^35 hashes starting with these 5 characters.
mynameismonkey 8y ago
I'm trying to figure out if I need to do this if I'm requiring minimum sixteen characters... after searching the docs and several of the blog posts, I can't ascertain if the corpus contains any passwords/phrases >= 16 characters. I don't want to be running this check on every passphrase create/modify if the corpus contains none or very very few passes length 16 or greater. Does anyone have any insight into the contents? Or, a way to query only the portion of the corpus that has 16 or greater?
- michaelbanfield 8y ago
  I just tried 'passwordpassword' and it was there. You can download the whole dataset at the bottom of this page https://haveibeenpwned.com/Passwords https://haveibeenpwned.com/Passwords Its a losing battle trying to add byzantine rules to prevent users doing things like using their normal password * 2, so its probably a reasonable check to add.
  - mynameismonkey 8y ago
    Aha, I tried a few obvious 16s but not that one... thank you! I guess we'll add it in. The last few dumps (other sources) I reviewed contained nothing over 15 characters, but I'm imagining they will start creeping in as more folks demand longer phrases. Still, I'd bet the vast majority of the bad passes are <16, seems a heck of a waste of energy and bandwidth to check my user's passphrases against (guesstimating) 0.05% of the corpus.
mrybczyn 8y ago
I also operate a password scanning service. Please private message me your username, password, and webservice URL. I will confirm whether it is a good combination.
minus7 8y ago
Would be nice if they made a bloom filter for anyone to use. On second thought, you can do that yourself based on the SHA-1 hashes of passwords they offer for download. Edit: On third thought, a bloom filter for 502M entries and a false positive rate of 0.1% ends up as a 800MiB large filter. Binary-searching the whole dump is surely faster.
- deleted 8y ago
  [deleted]
- Freaky 8y ago
  > a bloom filter for 502M entries and a false positive rate of 0.1% ends up as a 800MiB large filter With that sort of FP rate it's not really much use beyond filtering API calls. I'd suggest 2GB[1] as a more sensible minimum. A compressed filter can get this down somewhat. > Binary-searching the whole dump is surely faster. Not really. log2(500M) is ~29, k for a suitably sized bloom filter's only 23. Interpolation search can get you a result in more like 10 seeks, but a bucketed bloom filter can get your lookup down to a single read. Having spent a fair bit of time faffing about with this stuff I ended up settling[2][3] on Golomb compressed sets[4], which can get the full list with a 1-in-10 million FP rate into 1.5GB. [1]: https://hur.st/bloomfilter/?n=500M&p=1.0E-7 https://hur.st/bloomfilter/?n=500M&p=1.0E-7 [2]: https://github.com/Freaky/gcstool https://github.com/Freaky/gcstool [3]: https://github.com/Freaky/ruby-gcs https://github.com/Freaky/ruby-gcs [4]: http://giovanni.bajo.it/post/47119962313/golomb-coded-sets-smaller-than-bloom-filters http://giovanni.bajo.it/post/47119962313/golomb-coded-sets-s...
  - minus7 8y ago
    Oh right, I was wrongly thinking you'd have to memcmp the whole size of the filter. It's simply too warm today for thinking. Did you look into Cuckoo filters as well?
    - Freaky 8y ago
      > Oh right, I was wrongly thinking you'd have to memcmp the whole size of the filter. Yeah, it's just k single-bit lookups - ideally you do something to get them into clusters, like dividing the database into sub-filters, so you're doing random lookups into, say, a 32KB chunk instead of a whole 2GB filter. > Did you look into Cuckoo filters as well? Cuckoo filters look like an interesting alternative and looking at them more closely is on the to-do. I don't think they'd have any significant space savings, though - they're similarly about 75% the size of the equivalent bloom filter. Maybe they'd be faster for lookups? I'd also be interested in playing with matrix filters[1], which supposedly get close to the theoretical limits for these sorts of structures. Implementing them seems rather more involved, sadly - particularly given the only reference I can find is a fairly inscrutable CS paper. Show us the code damnit. [1]: https://arxiv.org/abs/0804.1845 https://arxiv.org/abs/0804.1845
perl4ever 8y ago
Soliciting people to enter their passwords seems like a bad approach both because it's risky and because it helps train people to do risky things - better would be a service that attempts to crack passwords and if it succeeds, disables the account until a new password is set. Seems like a service that everybody should use, if it existed. Much better than arbitrary rules about "good" password character sets.
- goodpass 8y ago
  There’s no one specific way to crack a password. It all depends on the implementation. The most basic case is just storing the password in plaintext, and plenty of companies are more than happy to do that. Passwords don’t exist as some separate entity, they’re attached to a system. So cracking an Adobe password might be easy, but cracking a Dropbox password incredinly hard.
  - perl4ever 8y ago
    I suppose. I was thinking of just hashing all known passwords and plausible passwords and locking any accounts that matched.

190 points by robin_reala 8y ago

The Okta chrome extension mentioned in the article seems very cool and useful. But how do we trust the Okta chrome extension not to post all credentials to the developer? Even if its doing nothing shady now, in some future update?

amdavidson 8y ago
With that security model, how do you trust any extension at all? At least with this one, you can audit the source code and build it for yourself[0] 0: https://github.com/OktaSecurityLabs/passprotect-chrome https://github.com/OktaSecurityLabs/passprotect-chrome
- willvarfar 8y ago
  I once made a webpage where HNers drag-dropped their entire iphone backups. It got me thinking. http://markolson.github.io/js-sqlite-map-thing/ http://markolson.github.io/js-sqlite-map-thing/
  - crtasm 8y ago
    It decrypts their backup locally? The link to code in the footer just refreshes the page.
    - willvarfar 8y ago
      It parses an unencrypted sqlite db in their backups in client-side javascript. The whole thing is client-side javascript. But... if we'd wanted to be nasty we could have sent everything to servers we controlled. The src link stopped working when gitlab.io arrived I think https://github.com/markolson/js-sqlite-map-thing/ https://github.com/markolson/js-sqlite-map-thing/
  - ReverseCold 8y ago
    Whenever there are tools like this I usually just visit the site then unplug my ethernet/disconnect from WiFi. If it's actually client side JS it will work. I'm pretty sure this is safe, but if there's a way to defer sending an HTTP request to after the page being closed...
    - phyzome 8y ago
      If you do it from a private browsing window, maybe that would be fine. Maybe. (Otherwise the page could exfiltrate information via localstorage or something.)
    - willvarfar 8y ago
      You'd just motivate me to use client-side storage if the upload failed. Don't dare come back to the page when online! :)

programbreeding 8y ago

I'm a huge fan of Troy Hunt and HIBP, but reading this I assumed it was basically an advertisement to get people to sign up for the Pwned Passwords API -- I admit I didn't make it down to the "And Finally..." section where he explains that it's free because there were a bunch of pictures at the bottom and I stopped reading. But reading through the API docs [0] it shows that API has no rate limit. Impressive. [0] https://haveibeenpwned.com/API/v2#SearchingPwnedPasswordsByPassword https://haveibeenpwned.com/API/v2#SearchingPwnedPasswordsByP...

pit2 8y ago
Even if he's not charging for the service, I am pretty sure he's getting more consultancy work from these "PR" (notice the quotes) posts. Even the timing on which he releases them makes sense in a way to prevent people from getting too tired of this service. Not saying is a bad thing but don't assume something is for pure altruism because not many things are.
- Arnt 8y ago
  Have you ever been paid to do work that you really want to happen? Been paid to improve the world in a small, but significant way? It's a lovely feeling.
  - PietdeVries 8y ago
    But what is the value-add of this service? Complex passwords are quite useful if the server gets hacked and someone walks away with the (salted) password hashes. Against brute-forcing passwords at the login screen of an application they don't add much value, other than making it the user quite hard to remember what the password for this particular site could be... Theoretically, if you block a user ID after say 5 or so invalid logins, almost any bad password from the Have I been P0wned list will prevent you from being hacked. The chance that you pick exactly that password from the 1-million or so list is quite minimal. So with that in mind, wouldn't this service be something for website owners that don't know how to properly secure the information they control?

qrbLPHiKpiux 8y ago

Great in theory, I don’t think it will play out good because of the average computer user. Ask any help desk employee.

teknopaul 8y ago
Word. Password security should be proportional to chance of a dictionary attack * risk of a successful attack. Mozilla want a 12 character passwords to file a bug report when they really should publish an email address an anonymous html form and say please.
- robin_reala 8y ago
  They do? Help / Submit Feedback / Firefox makes me sad, then fill in the form.
- kikoreis 8y ago
  I know what you are feeling, but there's a balance to making bug filing easy. For a large visible project, make it easy and the statistical noise drowns everything out.

mkirklions 8y ago

The only thing I had a hard time understanding- OP really cares about his privacy/security/password, but then he uses a secondary system to store it? Is this the best way to do this? Break into the secondary system and everything is available. Keyloggers, eyes, stolen computers, all have the possibility of everything available. I considered other solutions like written + put in a lock box in a bank, but thats really inaccessable.

rjacksonm1 8y ago
It is the best way to do it for the average user. Modern password management services are incredibly secure, with client-side encryption of your secrets, among other protective mechanisms (to guard against keyloggers, stolen computers, ...) There is still a risk, because you're trusting third-party software (which in some cases is closed-source – including 1Password), but for most people that is a much lower risk profile than if they were managing passwords themselves. For specifics on 1password's security, check out https://1password.com/security/ https://1password.com/security/
- willvarfar 8y ago
  > Modern password management services are incredibly secure There lots of password managers that have had gaping vulnerabilities. From memory I'm sure I've seen LastPass vulnerabilities top HN just a while ago... yeah probably this one: https://www.bankinfosecurity.com/lastpass-patches-password-manager-vulnerability-a-9299 https://www.bankinfosecurity.com/lastpass-patches-password-m...
SCdF 8y ago
It does sound a bit silly, but the alternative is to keep them in your brain, and AFAICT it's impossible to do that these days. I have hundreds of accounts in my password manager, I couldn't possibly remember secure passwords for all of them. FWIW I'm not a fan of keeping them in some cloud service dedicated for storing passwords (1PW's subscription offering, lastpass) because if someone is going to break into servers and steal passwords it's going to be from those fine people. A middle ground is to use something like KeePass, where the encrypted password file is stored where you want it to be stored (ie your hard drive), where you can manage how you want to distribute that file between places you need it.

sethgecko 8y ago

I wrote this small python function to check if a password is part of a breach by transmitting only the first 5 digits of it's hash: https://gist.github.com/mcdallas/d94ecd8b34a6bf57a162a7af0ce2a664 https://gist.github.com/mcdallas/d94ecd8b34a6bf57a162a7af0ce...

rahimnathwani 8y ago
Your code uses the first 5 digits of the hex digest of the SHA1. This 5-digit hex number has roughly 1 million combinations. That seems way too low. For context: If you take just dictionary words from the world's 5 most popular languages, you'd have more than 0.5 million words.
- sethgecko 8y ago
  This is from the API docs, you are not allowed to pick the number of digits. https://haveibeenpwned.com/API/v2#SearchingPwnedPasswordsByRange https://haveibeenpwned.com/API/v2#SearchingPwnedPasswordsByR...
  - rahimnathwani 8y ago
    Oh I see, so you send only the first 5 digits, but you then get back ~16,730 digits (478 * (40-5)) and search those for your full hash.
- qop 8y ago
  So what if you then took positives from 5dig hash matches and searched then through 7dig hash matches? Like a sieve? With a good cache, thatd save some bandwidth. Maybe that's wishful thinking. I can't imagine checking new passwords more than a few dozen times per second at the most. Bigger sites probably just write their own password integrity tools.
  - mrybczyn 8y ago
    I applaud your optimism! Most places just enforce byzantine password requirements, 13 digits, must have ~, uppercase and a palindrome prime integer in it. Obligatory password XKCD, think of the children. https://xkcd.com/936/ https://xkcd.com/936/

ransom1538 8y ago

Stupid question here. But shouldn't websites/apps simply lock the account for 5 minutes after 3 bad password attempts? -- basically ending the usefulness of bad password lists, etc etc. Do sites actually let you run limitless password attempts -- thus really find these password lists important? If your password was "foofoo", and there was a password lock after 3 attempts I don't see how you would crack it with a password file (in this lifetime).

snowwolf 8y ago
Because the email/password combination is already known. From a previous breach where you used the same combination. So the attacker needs exactly 1 attempt to get into your account. And with the ease of using botnets now, they can get access to a very large number of IPs to distribute the attack, so you can't reliably throttle at IP level either.
elorant 8y ago
I've tried that once in a site and it was a maintenance nightmare. Users kept bombarding me with emails asking to unlock their accounts. Turns out 99 times out of 100 that a username/password combo has been mistyped it's from users jerking around or not remembering the password, rather from hackers trying to brute force their entrance. Now imagine having a site with a few million accounts and 0,1% of them mistyping the password every now and then.
- ransom1538 8y ago
  You don't have a 'forgot password' system?
- paulpauper 8y ago
  One could set the threshold to 40 failed attempts. brute forcing requires thousands of attempts.
- scient 8y ago
  Sounds like a case of not handling the UX of the feature properly. What you can do is either allow them to unlock the account via email, or have a time-based unlock, or both. We do 72 hours or unlock it via email.

paulpauper 8y ago

reminder: never enter your email on one of those 'have i been pwned databases' . Find a way to download the database offline and then check it.

SmellyGeekBoy 8y ago
I'm signed up his automated alerts whenever my email appears on a leaked password list online. I had one through just the other day, then a load of alerts that my Ubisoft account was being accessed from various places all over the world (I have no idea when/why I set up a Ubisoft account, but there you go). It's a very useful service - and free. No way am I going to manually download every single password dump that appears online and search it for my details.
- ummonk 8y ago
  Same for my Ubisoft account last night. I've been using 1password for all my new passwords, but obviously there are still old accounts lying around with overused passwords of mine.
forgotmypw 8y ago
Not sure why this was voted down. By entering your email, you are providing lots of valuable data to a potential attacker: that you are active, your IP address and environment, all of which can help unlock your account on whatever service was compromised.
- moviuro 8y ago
  Who could possibly get this info on https://haveibeenpwned.com https://haveibeenpwned.com ? Troy? I bet he doesn't even keep logs. Anyone listening to your HTTPS connections? Then you have some more serious issues. No seriously, Troy's site is awesome, and spreading FUD is not doing them any service.
  - jsmeaton 8y ago
    It’s good advice in general for most folks. For those that know of Troy and this particular site it’s fine, but the general recommendation still stands.

Animats 8y ago

they gave people the ability to check any individual password against the online Pwned Passwords service What could possibly go wrong? This works by locally hashing your password, then sending only the first 5 hex characters of the hash to the server. The server sends back all matching hashes of bad passwords it has on file. Typically this returns a few hundred hits. The local client (probably some piece of Javascript) checks the hits against the password hashes returned. If there's a match, the password is in the database of bad passwords. This supposedly protects the password if communications with the checker are intercepted. But does it? If an attacker can see those first 5 hex characters, they too can get the list of hashes of matching passwords. There are only a few hundred of them, and they're hashes, not the actual passwords. One of those is the hash of the user's password. Now they know what hashes to try. An attacker presumably has a big database of likely passwords to try. So they can create a database of hashes locally. The hashing algorithm is known to the client, after all. So now they have a few hundred passwords to try for a break-in. Try those over the next few days, and they're in. Is it really that bad, or am I misunderstanding something here?

jxcl 8y ago
The point of a secure password is that it _won't_ be in the list of hashes by the server. The service should prevent the user from using any of the passwords that are matched by the password database.
0xdeadbeefbabe 8y ago
That doesn't sound so bad. Real attackers probably try something easier first.
jandrese 8y ago
The point is if you get a match you deny that password and make the user try again. So this would only give you a list of 100 or so passwords that it couldn't be. Not even a drop in the bucket of the namespace you need to search.
drexlspivey 8y ago
> One of those is the hash of the user's password. Why? Your hash might not be in the list. There are 16^35 hashes starting with these 5 characters.

mynameismonkey 8y ago

I'm trying to figure out if I need to do this if I'm requiring minimum sixteen characters... after searching the docs and several of the blog posts, I can't ascertain if the corpus contains any passwords/phrases >= 16 characters. I don't want to be running this check on every passphrase create/modify if the corpus contains none or very very few passes length 16 or greater. Does anyone have any insight into the contents? Or, a way to query only the portion of the corpus that has 16 or greater?

michaelbanfield 8y ago
I just tried 'passwordpassword' and it was there. You can download the whole dataset at the bottom of this page https://haveibeenpwned.com/Passwords https://haveibeenpwned.com/Passwords Its a losing battle trying to add byzantine rules to prevent users doing things like using their normal password * 2, so its probably a reasonable check to add.
- mynameismonkey 8y ago
  Aha, I tried a few obvious 16s but not that one... thank you! I guess we'll add it in. The last few dumps (other sources) I reviewed contained nothing over 15 characters, but I'm imagining they will start creeping in as more folks demand longer phrases. Still, I'd bet the vast majority of the bad passes are <16, seems a heck of a waste of energy and bandwidth to check my user's passphrases against (guesstimating) 0.05% of the corpus.

mrybczyn 8y ago

I also operate a password scanning service. Please private message me your username, password, and webservice URL. I will confirm whether it is a good combination.

minus7 8y ago

Would be nice if they made a bloom filter for anyone to use. On second thought, you can do that yourself based on the SHA-1 hashes of passwords they offer for download. Edit: On third thought, a bloom filter for 502M entries and a false positive rate of 0.1% ends up as a 800MiB large filter. Binary-searching the whole dump is surely faster.

deleted 8y ago
[deleted]
Freaky 8y ago
> a bloom filter for 502M entries and a false positive rate of 0.1% ends up as a 800MiB large filter With that sort of FP rate it's not really much use beyond filtering API calls. I'd suggest 2GB[1] as a more sensible minimum. A compressed filter can get this down somewhat. > Binary-searching the whole dump is surely faster. Not really. log2(500M) is ~29, k for a suitably sized bloom filter's only 23. Interpolation search can get you a result in more like 10 seeks, but a bucketed bloom filter can get your lookup down to a single read. Having spent a fair bit of time faffing about with this stuff I ended up settling[2][3] on Golomb compressed sets[4], which can get the full list with a 1-in-10 million FP rate into 1.5GB. [1]: https://hur.st/bloomfilter/?n=500M&p=1.0E-7 https://hur.st/bloomfilter/?n=500M&p=1.0E-7 [2]: https://github.com/Freaky/gcstool https://github.com/Freaky/gcstool [3]: https://github.com/Freaky/ruby-gcs https://github.com/Freaky/ruby-gcs [4]: http://giovanni.bajo.it/post/47119962313/golomb-coded-sets-smaller-than-bloom-filters http://giovanni.bajo.it/post/47119962313/golomb-coded-sets-s...
- minus7 8y ago
  Oh right, I was wrongly thinking you'd have to memcmp the whole size of the filter. It's simply too warm today for thinking. Did you look into Cuckoo filters as well?
  - Freaky 8y ago
    > Oh right, I was wrongly thinking you'd have to memcmp the whole size of the filter. Yeah, it's just k single-bit lookups - ideally you do something to get them into clusters, like dividing the database into sub-filters, so you're doing random lookups into, say, a 32KB chunk instead of a whole 2GB filter. > Did you look into Cuckoo filters as well? Cuckoo filters look like an interesting alternative and looking at them more closely is on the to-do. I don't think they'd have any significant space savings, though - they're similarly about 75% the size of the equivalent bloom filter. Maybe they'd be faster for lookups? I'd also be interested in playing with matrix filters[1], which supposedly get close to the theoretical limits for these sorts of structures. Implementing them seems rather more involved, sadly - particularly given the only reference I can find is a fairly inscrutable CS paper. Show us the code damnit. [1]: https://arxiv.org/abs/0804.1845 https://arxiv.org/abs/0804.1845

perl4ever 8y ago

Soliciting people to enter their passwords seems like a bad approach both because it's risky and because it helps train people to do risky things - better would be a service that attempts to crack passwords and if it succeeds, disables the account until a new password is set. Seems like a service that everybody should use, if it existed. Much better than arbitrary rules about "good" password character sets.

goodpass 8y ago
There’s no one specific way to crack a password. It all depends on the implementation. The most basic case is just storing the password in plaintext, and plenty of companies are more than happy to do that. Passwords don’t exist as some separate entity, they’re attached to a system. So cracking an Adobe password might be easy, but cracking a Dropbox password incredinly hard.
- perl4ever 8y ago
  I suppose. I was thinking of just hashing all known passwords and plausible passwords and locking any accounts that matched.