Yevgeniy Nikulin.Downloading the Pwned Passwords list. Passwords for nearly 6.5 million user accounts were stolen. After a search we display all available information from the hacked site.There are two common failings, over and above letting the databases or files get stolen in the first place.The 2012 LinkedIn hack refers to the computer hacking of LinkedIn on June 5, 2012. We allow our users to search for emails, names and usernames, ip address, phones, hashes or even passwords so they can find out if their information has been leaked. Snusbase indexes information from websites that have been hacked and had their database leaked.Most institutions simply don't implement this level of security.When you hear that passwords got stolen, sometimes companies will report it even if it's just hashed passwords that were stolen. Computing their own hash set is certainly possible, but it's extremely time consuming (as in months or longer), so it's generally the vanilla hash that's vulnerable.Using a salt stops rainbow tables, and a high round count of hashed hashes of hashes can make brute force transition from months to years or longer. A good rainbow table can support a high percentage match in fractions of a second per password hash.Using a salt ( an extra non-secret extension of the password) in the hash prevents the use of pre-computed rainbow tables.Most compromisers depend upon rainbow tables. In fact, what usually happens is that tables of pre-computed passwords and hashes (Rainbow Tables) are available and used to look for matches. Offering username, email, ipaddress look-ups over thousands of data breaches / dumps, its easy Hashed passwords are technically not reversible, but as has been pointed out by others, it's possible to hash millions of password guesses then simply look for matches.
Leaked Database Cracked Quite QuicklyBrute force cracking is feasible because people do not usually choose highly unpredictable passwords.When a password database is stolen, the stolen material includes all the information necessary to do offline cracking. However, there are plenty of examples where companies do not store passwords correctly leading them to be cracked quite quickly.You hash a large number of potential passwords *, then check whether each output matches any hashes from the stolen password database. In short, if a company follows recommended password storage methods, the passwords in theory should be safe in their hashed form, but a good company will still inform their customers of the breach. Other times, companies use hashing on their passwords but use insecure hashing algorithms or they don't salt their passwords properly. In other cases, such as the Adobe password breach, there was mishandling of storing the encrypted passwords in their database. Unfortunately, there are still companies that store their passwords incorrectly for example, if you search for the rockyou password breach, you'll find that they were storing their passwords in clear text, which means that they were compromised as soon as they were stolen.Leaked Database Full List OfIf password hashes are unsalted or all use the same salt it's a lot easier to do untargeted attacks you would only need to hash a candidate password once to figure out the full list of users that had that password. If multiple accounts are being targeted then the password you want to try has to be hashed one time for each salt. If each account uses a unique salt then crackers can't simply target everyone by hashing every candidate password once. Other methods may be available with less secure hashing or password storage methods.)* If salts are used, then the cracker must consider those too. System tools menu(Alternative passwords not identical to the original.)The accounts of users from the company with the data breach are still vulnerable because these passwords will unlock a user's account, even if they aren't identical to the original password. (An inhumanly strong password.)However, most people don't do this in the real world, a stolen database of hashes is potentially as worrying as a list of unhashed passwords for a large subset of users on a typical website.If the password cracker finds candidate password whose hash matches the one stored in the database, then he will have recovered the original (weak) password.Alternatively, if a hash function is not preimage resistant (including when the output of the hash is too short) a guess-and-check procedure may produce false positives. Those nuances aside, the basis of password cracking remains a guess and check process.Hashing passwords with a preimage resistant functions with a sufficiently unpredictable input is enough to make it impossible recover a password. Salts DO NOT reduce the number of hashes that need to be evaluated if only one account is being targeted. Sadly, even today, there are still plenty of passwords stored as cleartext. (Weak passwords will still be crackable.)Even though passwords should be hashed before storage, it's not always the case. Argon2 specifically can go a very long way to reduce the fraction of hashes which will get cracked. (For both legitimate users and password crackers.) Argon2 is currently the best password stretching algorithm, especially on Intel/ARM CPUs. These algorithms just try to make password hashing more expensive. But strong passwords are no good if passwords aren't hashed.Developers should use a password stretching algorithm. You reverse this table so it becomes hash -> password ( lookup table). So you build a list of password -> hash combinations based on all sorts of passwords. Steal logs, get all passwords that were used in those logs.Passwords could be hashed but not salted. Passwords could be included in logs, for instance. 360 degree video stitching softwareSame as #4-7, but you can do a lot more attempts a lot more quickly, so you can try a larger dictionary, or even try quite systematically all combinations ( brute force attack).Communication between clients and servers are susceptible to man-in-the-middle (MITM) attacks. If you have the date the initial password was valid and know the password change interval, it can be quite quick.Passwords are hashed and salted, but use weak (fast) hashes. Get database, make a dictionary attack on hashes, get lots of passwords.Variation on the previous one, instead of a pre-determined list of passwords, try passwords based on other information you have about the user (username, first name, last name, date of birth, e-mail.).Yet another variation, as many users re-use the same password: try passwords for the same e-mail/username recovered from other breaches.Yet another variation, when there is a strong password policy in place which requires changing passwords on a regular basis: if you have a previous password for the user, just try changing the final numbers: if user had password "joe12" at one point, try joe13, joe14, joe15. Try lists of passwords against those hashes. But lots of users use very weak passwords (123456, password, letmein, qwerty.). If we don't, when there is a data breach attackers can view passwords in what may as well be plain text, as often is the case (depending on the way in which these are stored).In short, you'd never want this to happen! - Password cracking is a very common and real thing, just because passwords are hashed does not make them in any way secure.Let's say a company has 1000 customer passwords, all of which are hashed. Could be as easy as a stored XSS hack.There's probably quite a few more methods, but that gives you an idea of how easy it can be to recover tons of passwords.As we are not discussing how the passwords have been stolen, and more so the aftermath, I'll avoid the many number of factors said companies should implement to help prevent these data breaches.If you make a website and manage the database, it's down to us to store that information efficiently. "Hello, this is the IT department, there's an issue with your account, we need to reset something, can you give me your password"? You'd be amazed how often that works if properly framed.Mass social engineering, aka phishing: send a mass e-mail campaign asking to log into a site which will capture all those passwords.Hack into the site, and modify it so it sends all passwords received to a remote server (or logs them to a file you'll retrieve later).Ditto, but modify client-side code to do it.
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