Mixing
What could an attacker do if they gained access to PBKDF2 hashes?
Clash Royale CLAN TAG#URR8PPP
.everyoneloves__top-leaderboard:empty,.everyoneloves__mid-leaderboard:empty margin-bottom:0;
up vote
7
down vote
favorite
This is regarding a web application where a user has to login with their personal email as the ID, and a password they have chosen personally.
If an attacker somehow gained access to a credential store with a list of all the PBKDF2 hashes with the email addresses, to what extent could this be used maliciously?
passwords cryptography hash pbkdf2
asked 2 days ago
deltzy
525
add a comment |Â
up vote
7
down vote
favorite
This is regarding a web application where a user has to login with their personal email as the ID, and a password they have chosen personally.
If an attacker somehow gained access to a credential store with a list of all the PBKDF2 hashes with the email addresses, to what extent could this be used maliciously?
passwords cryptography hash pbkdf2
asked 2 days ago
deltzy
525
When you say “a list of all the PBKDF2 hashesâ€Â, do you mean to imply that the list would also include the email address corresponding to each hash, which is the most likely scenario, or do you mean just the hashes?
– Mike Scott
2 days ago
They would also include the email addresses.
– deltzy
2 days ago
Is this web application using Peppers and Salts?
– Matthieu M.
2 days ago
This is a well-known scenario, and I'm pretty sure there's a duplicate of this question somewhere - aren't you basically asking "what's the consequences of a database breach with correctly hashed passwords" ?
– Riking
yesterday
add a comment |Â
up vote
7
down vote
favorite
up vote
7
down vote
favorite
This is regarding a web application where a user has to login with their personal email as the ID, and a password they have chosen personally.
If an attacker somehow gained access to a credential store with a list of all the PBKDF2 hashes with the email addresses, to what extent could this be used maliciously?
passwords cryptography hash pbkdf2
asked 2 days ago
deltzy
525
This is regarding a web application where a user has to login with their personal email as the ID, and a password they have chosen personally.
If an attacker somehow gained access to a credential store with a list of all the PBKDF2 hashes with the email addresses, to what extent could this be used maliciously?
passwords cryptography hash pbkdf2
passwords cryptography hash pbkdf2
asked 2 days ago
deltzy
525
asked 2 days ago
deltzy
525
edited 2 days ago
asked 2 days ago
deltzy
525
asked 2 days ago
deltzy
525
asked 2 days ago
deltzy
525
525
When you say “a list of all the PBKDF2 hashesâ€Â, do you mean to imply that the list would also include the email address corresponding to each hash, which is the most likely scenario, or do you mean just the hashes?
– Mike Scott
2 days ago
They would also include the email addresses.
– deltzy
2 days ago
Is this web application using Peppers and Salts?
– Matthieu M.
2 days ago
This is a well-known scenario, and I'm pretty sure there's a duplicate of this question somewhere - aren't you basically asking "what's the consequences of a database breach with correctly hashed passwords" ?
– Riking
yesterday
add a comment |Â
When you say “a list of all the PBKDF2 hashesâ€Â, do you mean to imply that the list would also include the email address corresponding to each hash, which is the most likely scenario, or do you mean just the hashes?
– Mike Scott
2 days ago
They would also include the email addresses.
– deltzy
2 days ago
Is this web application using Peppers and Salts?
– Matthieu M.
2 days ago
This is a well-known scenario, and I'm pretty sure there's a duplicate of this question somewhere - aren't you basically asking "what's the consequences of a database breach with correctly hashed passwords" ?
– Riking
yesterday
When you say “a list of all the PBKDF2 hashesâ€Â, do you mean to imply that the list would also include the email address corresponding to each hash, which is the most likely scenario, or do you mean just the hashes?
– Mike Scott
2 days ago
When you say “a list of all the PBKDF2 hashesâ€Â, do you mean to imply that the list would also include the email address corresponding to each hash, which is the most likely scenario, or do you mean just the hashes?
– Mike Scott
2 days ago
They would also include the email addresses.
– deltzy
2 days ago
They would also include the email addresses.
– deltzy
2 days ago
Is this web application using Peppers and Salts?
– Matthieu M.
2 days ago
Is this web application using Peppers and Salts?
– Matthieu M.
2 days ago
This is a well-known scenario, and I'm pretty sure there's a duplicate of this question somewhere - aren't you basically asking "what's the consequences of a database breach with correctly hashed passwords" ?
– Riking
yesterday
This is a well-known scenario, and I'm pretty sure there's a duplicate of this question somewhere - aren't you basically asking "what's the consequences of a database breach with correctly hashed passwords" ?
– Riking
yesterday
add a comment |Â
2 Answers
2
active
oldest
votes
up vote
9
down vote
accepted
The attacker would have to crack the hashes in order to obtain the original passwords. Since PBKDF2 does multiple iterations of the same hash function, the act of cracking them would be significantly slower. The end result is that even weaker passwords are less likely be revealed, leading to a significantly lower percentage of successfully cracked passwords in the credential list.
answered 2 days ago
forest
22k116886
3
Lists of hundreds of millions of previously-compromised passwords are freely available, and it’s perfectly feasible to run the whole of such a list against a few thousand leaked hashes. Experience shows that this will reveal 80% to 90% of all passwords. troyhunt.com/86-of-passwords-are-terrible-and-other-statistics
– Mike Scott
2 days ago
3
@MikeScott Quite a few are indeed terrible, but 80% or 90% is a lot more than it really is. Just compare a leaked MD5 hash list with a leaked bcrypt hash list. The former may have almost 50% cracked, whereas the latter may have under 10% cracked!
– forest
2 days ago
add a comment |Â
up vote
4
down vote
Assuming the attacker got the salts as well as the hashes, they could run a list of known previously used passwords against the list of hashes and get the passwords of most of the users, since the majority of users use passwords whose plain text has already been compromised somewhere. They couldn’t recover long well-chosen passwords that have never been used before.
answered 2 days ago
Mike Scott
6,6481328
While true, I'm not sure if this is especially applicable, as the attacker could just as easily take those leaked password lists and simply login to the website itself. The only thing they would really need to do that is the list of email addresses, so in this case the actual useful information from the leak would be the list of registered email addresses. The passwords themselves would actually be less valuable. It is true that offline cracking would be easier to setup and faster than attempting logins on the live site, but I don't think it would be a dramatic difference.
– Conor Mancone
2 days ago
10
There is indeed a dramatic difference between online and offline attack. Offline, you can quickly guess triillions (fast hashes) or hundreds of thousands / millions (slow hashes) of candidate passwords against a single account, discover original plaintext, and use it to immediately log into the site without triggering any alarms. Online, if targeting a single user, your IP address(es) and/or the target user's account is likely to get locked out after relatively small number of guesses. Password spraying can help in an online attack, but it's still massively less stealthy than offline attack.
– Royce Williams
2 days ago
add a comment |Â
2 Answers
2
active
oldest
votes
2 Answers
2
active
oldest
votes
active
oldest
votes
active
oldest
votes
up vote
9
down vote
accepted
The attacker would have to crack the hashes in order to obtain the original passwords. Since PBKDF2 does multiple iterations of the same hash function, the act of cracking them would be significantly slower. The end result is that even weaker passwords are less likely be revealed, leading to a significantly lower percentage of successfully cracked passwords in the credential list.
answered 2 days ago
forest
22k116886
3
Lists of hundreds of millions of previously-compromised passwords are freely available, and it’s perfectly feasible to run the whole of such a list against a few thousand leaked hashes. Experience shows that this will reveal 80% to 90% of all passwords. troyhunt.com/86-of-passwords-are-terrible-and-other-statistics
– Mike Scott
2 days ago
3
@MikeScott Quite a few are indeed terrible, but 80% or 90% is a lot more than it really is. Just compare a leaked MD5 hash list with a leaked bcrypt hash list. The former may have almost 50% cracked, whereas the latter may have under 10% cracked!
– forest
2 days ago
add a comment |Â
up vote
9
down vote
accepted
The attacker would have to crack the hashes in order to obtain the original passwords. Since PBKDF2 does multiple iterations of the same hash function, the act of cracking them would be significantly slower. The end result is that even weaker passwords are less likely be revealed, leading to a significantly lower percentage of successfully cracked passwords in the credential list.
answered 2 days ago
forest
22k116886
3
Lists of hundreds of millions of previously-compromised passwords are freely available, and it’s perfectly feasible to run the whole of such a list against a few thousand leaked hashes. Experience shows that this will reveal 80% to 90% of all passwords. troyhunt.com/86-of-passwords-are-terrible-and-other-statistics
– Mike Scott
2 days ago
3
@MikeScott Quite a few are indeed terrible, but 80% or 90% is a lot more than it really is. Just compare a leaked MD5 hash list with a leaked bcrypt hash list. The former may have almost 50% cracked, whereas the latter may have under 10% cracked!
– forest
2 days ago
add a comment |Â
up vote
9
down vote
accepted
up vote
9
down vote
accepted
The attacker would have to crack the hashes in order to obtain the original passwords. Since PBKDF2 does multiple iterations of the same hash function, the act of cracking them would be significantly slower. The end result is that even weaker passwords are less likely be revealed, leading to a significantly lower percentage of successfully cracked passwords in the credential list.
answered 2 days ago
forest
22k116886
The attacker would have to crack the hashes in order to obtain the original passwords. Since PBKDF2 does multiple iterations of the same hash function, the act of cracking them would be significantly slower. The end result is that even weaker passwords are less likely be revealed, leading to a significantly lower percentage of successfully cracked passwords in the credential list.
answered 2 days ago
forest
22k116886
answered 2 days ago
forest
22k116886
answered 2 days ago
forest
22k116886
answered 2 days ago
forest
22k116886
22k116886
3
Lists of hundreds of millions of previously-compromised passwords are freely available, and it’s perfectly feasible to run the whole of such a list against a few thousand leaked hashes. Experience shows that this will reveal 80% to 90% of all passwords. troyhunt.com/86-of-passwords-are-terrible-and-other-statistics
– Mike Scott
2 days ago
3
@MikeScott Quite a few are indeed terrible, but 80% or 90% is a lot more than it really is. Just compare a leaked MD5 hash list with a leaked bcrypt hash list. The former may have almost 50% cracked, whereas the latter may have under 10% cracked!
– forest
2 days ago
add a comment |Â
3
Lists of hundreds of millions of previously-compromised passwords are freely available, and it’s perfectly feasible to run the whole of such a list against a few thousand leaked hashes. Experience shows that this will reveal 80% to 90% of all passwords. troyhunt.com/86-of-passwords-are-terrible-and-other-statistics
– Mike Scott
2 days ago
3
@MikeScott Quite a few are indeed terrible, but 80% or 90% is a lot more than it really is. Just compare a leaked MD5 hash list with a leaked bcrypt hash list. The former may have almost 50% cracked, whereas the latter may have under 10% cracked!
– forest
2 days ago
3
3
Lists of hundreds of millions of previously-compromised passwords are freely available, and it’s perfectly feasible to run the whole of such a list against a few thousand leaked hashes. Experience shows that this will reveal 80% to 90% of all passwords. troyhunt.com/86-of-passwords-are-terrible-and-other-statistics
– Mike Scott
2 days ago
Lists of hundreds of millions of previously-compromised passwords are freely available, and it’s perfectly feasible to run the whole of such a list against a few thousand leaked hashes. Experience shows that this will reveal 80% to 90% of all passwords. troyhunt.com/86-of-passwords-are-terrible-and-other-statistics
– Mike Scott
2 days ago
3
3
@MikeScott Quite a few are indeed terrible, but 80% or 90% is a lot more than it really is. Just compare a leaked MD5 hash list with a leaked bcrypt hash list. The former may have almost 50% cracked, whereas the latter may have under 10% cracked!
– forest
2 days ago
@MikeScott Quite a few are indeed terrible, but 80% or 90% is a lot more than it really is. Just compare a leaked MD5 hash list with a leaked bcrypt hash list. The former may have almost 50% cracked, whereas the latter may have under 10% cracked!
– forest
2 days ago
add a comment |Â
up vote
4
down vote
Assuming the attacker got the salts as well as the hashes, they could run a list of known previously used passwords against the list of hashes and get the passwords of most of the users, since the majority of users use passwords whose plain text has already been compromised somewhere. They couldn’t recover long well-chosen passwords that have never been used before.
answered 2 days ago
Mike Scott
6,6481328
While true, I'm not sure if this is especially applicable, as the attacker could just as easily take those leaked password lists and simply login to the website itself. The only thing they would really need to do that is the list of email addresses, so in this case the actual useful information from the leak would be the list of registered email addresses. The passwords themselves would actually be less valuable. It is true that offline cracking would be easier to setup and faster than attempting logins on the live site, but I don't think it would be a dramatic difference.
– Conor Mancone
2 days ago
10
There is indeed a dramatic difference between online and offline attack. Offline, you can quickly guess triillions (fast hashes) or hundreds of thousands / millions (slow hashes) of candidate passwords against a single account, discover original plaintext, and use it to immediately log into the site without triggering any alarms. Online, if targeting a single user, your IP address(es) and/or the target user's account is likely to get locked out after relatively small number of guesses. Password spraying can help in an online attack, but it's still massively less stealthy than offline attack.
– Royce Williams
2 days ago
add a comment |Â
up vote
4
down vote
Assuming the attacker got the salts as well as the hashes, they could run a list of known previously used passwords against the list of hashes and get the passwords of most of the users, since the majority of users use passwords whose plain text has already been compromised somewhere. They couldn’t recover long well-chosen passwords that have never been used before.
answered 2 days ago
Mike Scott
6,6481328
While true, I'm not sure if this is especially applicable, as the attacker could just as easily take those leaked password lists and simply login to the website itself. The only thing they would really need to do that is the list of email addresses, so in this case the actual useful information from the leak would be the list of registered email addresses. The passwords themselves would actually be less valuable. It is true that offline cracking would be easier to setup and faster than attempting logins on the live site, but I don't think it would be a dramatic difference.
– Conor Mancone
2 days ago
10
There is indeed a dramatic difference between online and offline attack. Offline, you can quickly guess triillions (fast hashes) or hundreds of thousands / millions (slow hashes) of candidate passwords against a single account, discover original plaintext, and use it to immediately log into the site without triggering any alarms. Online, if targeting a single user, your IP address(es) and/or the target user's account is likely to get locked out after relatively small number of guesses. Password spraying can help in an online attack, but it's still massively less stealthy than offline attack.
– Royce Williams
2 days ago
add a comment |Â
up vote
4
down vote
up vote
4
down vote
Assuming the attacker got the salts as well as the hashes, they could run a list of known previously used passwords against the list of hashes and get the passwords of most of the users, since the majority of users use passwords whose plain text has already been compromised somewhere. They couldn’t recover long well-chosen passwords that have never been used before.
answered 2 days ago
Mike Scott
6,6481328
Assuming the attacker got the salts as well as the hashes, they could run a list of known previously used passwords against the list of hashes and get the passwords of most of the users, since the majority of users use passwords whose plain text has already been compromised somewhere. They couldn’t recover long well-chosen passwords that have never been used before.
answered 2 days ago
Mike Scott
6,6481328
edited 2 days ago
answered 2 days ago
Mike Scott
6,6481328
answered 2 days ago
Mike Scott
6,6481328
answered 2 days ago
Mike Scott
6,6481328
6,6481328
While true, I'm not sure if this is especially applicable, as the attacker could just as easily take those leaked password lists and simply login to the website itself. The only thing they would really need to do that is the list of email addresses, so in this case the actual useful information from the leak would be the list of registered email addresses. The passwords themselves would actually be less valuable. It is true that offline cracking would be easier to setup and faster than attempting logins on the live site, but I don't think it would be a dramatic difference.
– Conor Mancone
2 days ago
10
There is indeed a dramatic difference between online and offline attack. Offline, you can quickly guess triillions (fast hashes) or hundreds of thousands / millions (slow hashes) of candidate passwords against a single account, discover original plaintext, and use it to immediately log into the site without triggering any alarms. Online, if targeting a single user, your IP address(es) and/or the target user's account is likely to get locked out after relatively small number of guesses. Password spraying can help in an online attack, but it's still massively less stealthy than offline attack.
– Royce Williams
2 days ago
add a comment |Â
While true, I'm not sure if this is especially applicable, as the attacker could just as easily take those leaked password lists and simply login to the website itself. The only thing they would really need to do that is the list of email addresses, so in this case the actual useful information from the leak would be the list of registered email addresses. The passwords themselves would actually be less valuable. It is true that offline cracking would be easier to setup and faster than attempting logins on the live site, but I don't think it would be a dramatic difference.
– Conor Mancone
2 days ago
10
There is indeed a dramatic difference between online and offline attack. Offline, you can quickly guess triillions (fast hashes) or hundreds of thousands / millions (slow hashes) of candidate passwords against a single account, discover original plaintext, and use it to immediately log into the site without triggering any alarms. Online, if targeting a single user, your IP address(es) and/or the target user's account is likely to get locked out after relatively small number of guesses. Password spraying can help in an online attack, but it's still massively less stealthy than offline attack.
– Royce Williams
2 days ago
While true, I'm not sure if this is especially applicable, as the attacker could just as easily take those leaked password lists and simply login to the website itself. The only thing they would really need to do that is the list of email addresses, so in this case the actual useful information from the leak would be the list of registered email addresses. The passwords themselves would actually be less valuable. It is true that offline cracking would be easier to setup and faster than attempting logins on the live site, but I don't think it would be a dramatic difference.
– Conor Mancone
2 days ago
While true, I'm not sure if this is especially applicable, as the attacker could just as easily take those leaked password lists and simply login to the website itself. The only thing they would really need to do that is the list of email addresses, so in this case the actual useful information from the leak would be the list of registered email addresses. The passwords themselves would actually be less valuable. It is true that offline cracking would be easier to setup and faster than attempting logins on the live site, but I don't think it would be a dramatic difference.
– Conor Mancone
2 days ago
10
10
There is indeed a dramatic difference between online and offline attack. Offline, you can quickly guess triillions (fast hashes) or hundreds of thousands / millions (slow hashes) of candidate passwords against a single account, discover original plaintext, and use it to immediately log into the site without triggering any alarms. Online, if targeting a single user, your IP address(es) and/or the target user's account is likely to get locked out after relatively small number of guesses. Password spraying can help in an online attack, but it's still massively less stealthy than offline attack.
– Royce Williams
2 days ago
There is indeed a dramatic difference between online and offline attack. Offline, you can quickly guess triillions (fast hashes) or hundreds of thousands / millions (slow hashes) of candidate passwords against a single account, discover original plaintext, and use it to immediately log into the site without triggering any alarms. Online, if targeting a single user, your IP address(es) and/or the target user's account is likely to get locked out after relatively small number of guesses. Password spraying can help in an online attack, but it's still massively less stealthy than offline attack.
– Royce Williams
2 days ago
add a comment |Â
Sign up or log in
StackExchange.ready(function ()
StackExchange.helpers.onClickDraftSave('#login-link');
);
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
StackExchange.ready(
function ()
StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fsecurity.stackexchange.com%2fquestions%2f193366%2fwhat-could-an-attacker-do-if-they-gained-access-to-pbkdf2-hashes%23new-answer', 'question_page');
);
Post as a guest
Sign up or log in
StackExchange.ready(function ()
StackExchange.helpers.onClickDraftSave('#login-link');
);
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Sign up or log in
StackExchange.ready(function ()
StackExchange.helpers.onClickDraftSave('#login-link');
);
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Sign up or log in
StackExchange.ready(function ()
StackExchange.helpers.onClickDraftSave('#login-link');
);
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
When you say “a list of all the PBKDF2 hashesâ€Â, do you mean to imply that the list would also include the email address corresponding to each hash, which is the most likely scenario, or do you mean just the hashes?
– Mike Scott
2 days ago
They would also include the email addresses.
– deltzy
2 days ago
Is this web application using Peppers and Salts?
– Matthieu M.
2 days ago
This is a well-known scenario, and I'm pretty sure there's a duplicate of this question somewhere - aren't you basically asking "what's the consequences of a database breach with correctly hashed passwords" ?
– Riking
yesterday