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If the LastPass service has all my passwords and someone gets access to my LastPass password, this person will have access to all my passwords. Isn't that bad for security?

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Related: security.stackexchange.com/q/19236/953 –  Iszi Jan 28 '13 at 16:38
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Security isn't boolean; it is a risk based decision. Strictly speaking, any security policy that doesn't result in immediate and public execution by torture of any employee who violates the policy is bad for security. The real question is, "Does LastPass diminish risk more cost effectively than the other alternatives under consideration." In most real world scenarios, that answer is solidly yes. (because the alternatives are password re-use and bad passwords). –  Mark C. Wallace Jan 28 '13 at 18:42
    
"doesn't result in immediate and public execution by torture" ... really? –  DeepSpace101 Jun 15 '13 at 6:09
    
Just noting something not mentioned so far: Having a single email address for services that require them creates almost the exact same vulnerability, as most services that require an e-mail and password allow you to reset the password via e-mail. –  00500005 Jun 28 '13 at 14:30
    
@Sid that was just some irony, and a tought one because... well, sometimes users never look after the policies :-) –  woliveirajr Jun 28 '13 at 15:30

8 Answers 8

up vote 16 down vote accepted

That's why you need to make sure you change that password regularly and make it incredible strong. (I try to surpass 128 bits)

If you don't use passwordmanagers and need to insert a lot of different passwords, you might end up re-using passwords, which is even worse. I personally always recommend to use password managers once you have to remember a lot of passwords.

Personal opinion: However I don't really like LastPass because it's webbased. Call me paranoia/conservative about it, I prefer to use a Keypass database (which is encrypted) offline or synced with Dropbox.

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You can get a offline copy of your database and a javascript app that can decrypt the database. Also the encryption is all done client side so the server is only storing binary blobs without access to the symmetric key. (that's why their "forgot your password" page does not give you a new password (it can't!), it just tells you your password hint you recorded at signup) –  Scott Chamberlain Jan 28 '13 at 12:28
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I know, but I don't really like it when stuff is encrypted with JS, look at Mega, they do it as well and they already discovered some XSS attack vectors. Like I said it's just my personal opinion :) –  Lucas Kauffman Jan 28 '13 at 12:29
    
Fair enough, good reason too. –  Scott Chamberlain Jan 28 '13 at 12:31
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@Null that is actually a much more unlikely event than XSS –  Lucas Kauffman Jan 28 '13 at 20:32
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Just FYI Dropbox did accidentally allow anyone in to download your keypass database -- techcrunch.com/2011/06/20/… –  Joe Siegrist Jan 29 '13 at 17:31

This concentration of password power is consubstantial with the concept of a password manager. A password manager is a tool to "remember" more passwords than what the human mind can cope with. With a password manager, it suffices to remember one password to gain access to all the others. But this means that knowing that one password is sufficient to gain access to all the stored passwords. This is unavoidable: I am just stating the obvious, twice, with two slightly distinct points of view.

To live with that, make your master password strong enough to deter attacks. 15 random letters and digits ought to be enough to thwart CPU-based attackers: if your password gets stolen, it will not be through a brute force attack. The usual rules for password hygiene still apply: generate your password(s) with randomness, not wit; don't type a password on a machine which could be infected with a key logger; beware of shoulder surfers.

Password renewal is a controversial issue. Changing your master password may "kick out" attackers would could steal your master password, but this would not change the site-specific passwords stored in the password manager, so the attacker is not totally evicted. Also, the possibility of an attacker stealing your master password is already serious enough: if the attacker got to that point, you are already in deep trouble. Password renewal is like protesting against the ambient wetness while on board the Titanic.

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One could have multiple password databases, a high security one and medium and a low with there own master passwords? It's still better than password reuse, and there is no longer a single point of failure. –  ewanm89 Jan 28 '13 at 19:44
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Yes, you can trade-off that way: more databases means more passwords to remember, but you get more damage containment. –  Thomas Pornin Jan 28 '13 at 19:47
    
@ewanm89 I have a high level of paranoia and memorize all passwords to important services (eg: bank accounts, my main email) and store the rest in password manager. So even if my password file is stolen with the key, I wouldn't have too many problems. –  Null Jan 28 '13 at 20:26
    
+1 for the password renewal part. –  northox Mar 28 '14 at 13:54
    
@Null If your password database is stolen and broken into, then your bank/email passwords might not be compromised. But, if either of those service providers' databases are stolen then your human-memorable password is much more vulnerable to being cracked than a randomly-generated password from a password manager would have been. –  Iszi May 14 at 14:07

There are two primary problems with sharing passwords for multiple accounts. Yes, one problem is that if one password gets figured out, then it gives much more access as a single point of failure, but the bigger problem is that the same password is stored in many different places. Thus, the surface area to attack is MUCH larger. If I use my same password on every site I visit, if ANY of those sites is compromised, now all sites are compromised.

If I have a different password everywhere and/or use a single set of credentials through the use of something like OAuth, then the surface area of attack is limited to the single OAuth provider or keystore. Using a keystore means that normally only single passwords would have to be changed for a compromised site and if your keystore is compromised, you have documentation of all the accounts that you have that need changing. If you are using OAuth, then only one place has to be changed to actually change all the login credentials.

Sure, both options are weaker than pure random passwords for every site with no record linking them anywhere, but they are also far more useable and balancing usability and risk mitigation is a big part of security. The "most secure" (ie most risk mitigation) is not always the best security decision.

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In case it has not already been mentioned, you can also set up 2-factor authentication (2FA) for your LastPass password manager (I have it set up). This would be a one-time password in addition to your master password. And if you chose the OATH standard (there are multiple options), then you can use the same software token app on your device that you probably use already for other 2FA enabled sites (such as Google Authenticator for your gmail, etc).

Since using 2FA is obviously an extra pain, you could selectively disable it depending on situations. For example, if you are pretty confident that you protect your mobile phone, you can turn off 2FA on your phone, but leave it on for any attempt to log into your LassPass vault from any other device.

For more detail:

https://lastpass.com/support.php?cmd=showfaq&id=1696

Regards.

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They are not necessarily less secure in the theoretical sense, but they are less secure in the purely pragmatic sense.

In theory, one good password is as humanly difficult to crack as 100. If you choose a good password and the password is handled cryptographically properly, it should offer a barrier against attack that is far beyond anything humans could achieve in the foreseeable future. One password or many separate passwords, it's just a question of whether the attacker is estimated to need a few millenia or many more millenia to get all your passwords. It's a moot distinction.

It's worth noting that using one encryption key to wrap multiple other encryption keys, which is analogous to passwords wrapping passwords, can be acceptable practice. There's nothing inherently bad about it.

Pragmatically speaking, though, it's obviously impossible for one password to be anything but less secure than many distinct ones. The most secure password manager we currently have is (all else equal) your brain; a software adjunct can only detract from it. It creates a choke point where one problem could compromise a lot of passwords. A mistake in password manager could leave all passwords in the clear, an evil agency need only install one backdoor, etc.

How do you make your password-manager as safe as possible? Broadly speaking:

  • Ensure the password-protection-password is high quality.

  • Ensure the password management software performs correctly. (For most of us, this simply comes down to trusting the author, the design they used, and independent audits.)

  • Ensure your usage of both the password and password manager is proper.

The practical answer to the question is: A password manager is not inherently less secure if you can meet all three of these broad requirements, but the last two are far easier said than done. You are probably going to need to do research on the exact password-manager you want to use.

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The pragmatic user would utilize Multifactor to protect their LastPass account - helpdesk.lastpass.com/security-options/… –  Joe Siegrist Jan 29 '13 at 17:28

depends how they are managing their private keys. Even if the encryption is happening client side, the db is still prone to rainbow table attack.

I work for SmartSignin, so I am going to be little biased here: What SmartSignin offers over other password managers is 100% air-tight security by making sure all the encryption happens client side, and that your private key never leaves the system. In addition to that, the SmartKey patent offers a unique key against each stored password, meaning even one record gets compromised, the other stay vaulted. The public key exchange takes place over an encrypted SSL tunnel ensures that the public key stay safe during the mandatory key exchange.

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Instead of just touting the benefits of your product, perhaps focus on possible risks of similar systems? Note that this is not a product comparison, and the original question wasn't even just about lastpass, it was asking "Are services like “LastPass” "... –  AviD Aug 17 '13 at 20:49

As far as things like rainbow table cracks or brute force or things like that, I don't think this is an issue. You can expect that LastPass will be using proper security practices (at least as much as you can expect it from other companies who store highly-sensitive info (PayPal, Google, etc)) and therefore can probably safely assume that there are no technical security holes.

If you feel safe making that assumption, then the only real possible point of failure is the master password. Anyone who knows that will know everything, anyone who doesn't will know nothing. At this point, since you only have to remember a single password, you should make that password as secure as possible (really long, weird characters, etc (BUT DON'T FORGET IT)). As long as it is not easily guessable, everything will remain secure.

In a world where everyone uses a unique string of 20+ characters for every password, yes, keeping them all in one pass is far less secure. However, in a world where the vast majority of people have the same password for every service, LastPass can greatly increase security. But even if you already use uniques for everything, LastPass can still add security. There's a good chance your passwords are not as secure as they could be (longer, add letters, uppercase, symbols, etc), and LastPass will happily remember a string of garbage for each password.

Finally, having a single password that can access all the other passwords, is bad, but it is still far better than having the actual same password everywhere. I trust major web companies with securing my password, but you can bet that most of those little hole-in-the-wall forums that require accounts are not putting much thought into storing your password. In this case, having uniques everywhere means that, even when some little insecure service you used two years ago gets hacked, your entire online world remains secure (because you can bet that the hackers will take those email/pw combinations that they got from the hole-in-the-wall forum and plug them in to the bigger

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If the LastPass service has all my passwords and someone gets access to my LastPass password, this person will have access to all my passwords. Isn't that bad for security?

This is why you should protect your LastPass account with a second factor of authentication. LastPass have several options available such as Google Authenticator, or Yubikey. Good security has multiple factors of authentication, such as something you know (your password) and something you have (your phone or Yubikey).

Are services like “LastPass” less secure, as they have all my passwords protected by a single password?

The other option is that you remember, or write down, all your passwords for all systems you use. The latter approach has the same problem as LastPass in that if someone gets at your list you are fully compromised. The former will be very difficult to do, unless you have the skills, time and patience of Derren Brown - remember you need unique passwords for every service, with a high degree of entropy in each password to make them secure.

This also has the additional risk that not all services are protected by multi factor authentication. Using LastPass to fill the password for these services effectively gives you two factor authentication for them as you need to be able to log into LastPass first. It also protects against phishing (if you use the browser extension) because it will only fill the password fields for sites with a hostname match (it will fill google.com but not goooogle.com).

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