4 ms·

Anybody know what hash they use at yahoo for account passwords?

by beezle 10y ago

user731955373 10y ago
rot13
KMag 10y ago
You're likely under-estimating the amount of CPU time they're willing to throw at the problem. If you have to ask, the answer is "not strong enough for your password. Change your Yahoo password. Change all other passwords that were shared. Stop sharing passwords across sites." On the other hand, my LinkedIn password was 15 base-64 characters, poorly hashed with just SHA-1. As a rough ballpark, cracking it on average comes out to about 500 times all of the work that has ever been put into BitCoin mining. I still changed my password after the breach. Why not?
- Fej 10y ago
  So salted bcrypt isn't relatively safe?
  - KMag 10y ago
    It's safer than, say, unsalted MD4 (NTLM). However, the specifics of the hash only make a difference if your password is weak. As long as the hash is non-invertible, use passwords containing at least 96 bits of entropy, and you're fine. I use https://github.com/kmag/store_password_gpg https://github.com/kmag/store_password_gpg , which is a 200-line Python script I wrote a while ago to generate a random password and encrypt it using gpg. Any decent password manager should allow you to generate unique, random, per-site passwords.
throwawayyahoo2 10y ago
for the longest time, it was unsalted MD5. it may still be. very easy to crack with a rainbow table.
- beezle 10y ago
  "hashed passwords (the vast majority with bcrypt) and, in some cases, encrypted or unencrypted security questions and answers" The went on to say they have unactivated all clear text security questions. Really, WTF Yahoo. Why bother hashing a pw if you are going to have plaintext security questions. Though at least they were not using MD5
  - jonknee 10y ago
    > Really, WTF Yahoo. Why bother hashing a pw if you are going to have plaintext security questions. If they had not hashed the passwords you would be able to login to millions of Yahoo accounts with this leaked data.
  - itsnotlupus 10y ago
    old accounts. the reason for the "vast majority" and "in some cases" terminology is very likely because the user records only get updated when the user logs in. for accounts that haven't been used in a long long time, it's possible you'd still find pre-bcrypt hashes and plain text question/answers. Regarding your last sentence, I think other comments have chimed in on what they believe the pre-bcrypt hashes were made with.
SloopJon 10y ago
Yahoo's announcement (link changed since some of these comments were posted) says the "vast majority" used bcrypt. I've been getting an "Unexpected sign-in attempt" email from Yahoo every day for the last couple of weeks, but I don't see any evidence that the attempts were successful.

Anybody know what hash they use at yahoo for account passwords?

by beezle 10y ago

Anybody know what hash they use at yahoo for account passwords?

user731955373 10y ago

rot13

KMag 10y ago

You're likely under-estimating the amount of CPU time they're willing to throw at the problem. If you have to ask, the answer is "not strong enough for your password. Change your Yahoo password. Change all other passwords that were shared. Stop sharing passwords across sites." On the other hand, my LinkedIn password was 15 base-64 characters, poorly hashed with just SHA-1. As a rough ballpark, cracking it on average comes out to about 500 times all of the work that has ever been put into BitCoin mining. I still changed my password after the breach. Why not?

Fej 10y ago
So salted bcrypt isn't relatively safe?
- KMag 10y ago
  It's safer than, say, unsalted MD4 (NTLM). However, the specifics of the hash only make a difference if your password is weak. As long as the hash is non-invertible, use passwords containing at least 96 bits of entropy, and you're fine. I use https://github.com/kmag/store_password_gpg https://github.com/kmag/store_password_gpg , which is a 200-line Python script I wrote a while ago to generate a random password and encrypt it using gpg. Any decent password manager should allow you to generate unique, random, per-site passwords.

throwawayyahoo2 10y ago

for the longest time, it was unsalted MD5. it may still be. very easy to crack with a rainbow table.

beezle 10y ago
"hashed passwords (the vast majority with bcrypt) and, in some cases, encrypted or unencrypted security questions and answers" The went on to say they have unactivated all clear text security questions. Really, WTF Yahoo. Why bother hashing a pw if you are going to have plaintext security questions. Though at least they were not using MD5
- jonknee 10y ago
  > Really, WTF Yahoo. Why bother hashing a pw if you are going to have plaintext security questions. If they had not hashed the passwords you would be able to login to millions of Yahoo accounts with this leaked data.
- itsnotlupus 10y ago
  old accounts. the reason for the "vast majority" and "in some cases" terminology is very likely because the user records only get updated when the user logs in. for accounts that haven't been used in a long long time, it's possible you'd still find pre-bcrypt hashes and plain text question/answers. Regarding your last sentence, I think other comments have chimed in on what they believe the pre-bcrypt hashes were made with.

SloopJon 10y ago

Yahoo's announcement (link changed since some of these comments were posted) says the "vast majority" used bcrypt. I've been getting an "Unexpected sign-in attempt" email from Yahoo every day for the last couple of weeks, but I don't see any evidence that the attempts were successful.