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What's wrong with passwords ? The info is in your head and in a physical booklet secured at home for backup. Its only weakness is is keylogger. A secret key pro

by chmike 13y ago

What's wrong with passwords ? The info is in your head and in a physical booklet secured at home for backup. Its only weakness is is keylogger. A secret key protected by password doesn't provide you more security. You can only connect from the computers having a copy of the key. If that computer is inaccessible or dead, or the private key is erased you can't log in. It also is exposed to keylogger. So I stay with password for now. It should be a secure password of course. Maybe use private keys and a password for backup recovery only.

oelmekki 13y ago
Password authentication is prone to bruteforce. With public key auth, even if someone has your passphrase, he also needs the private key to break into your server. Indeed, there's always the risk to lose your private key. That's why it's useful to have several : I have one on my desktop, one on my laptop and one on my mobile. If any get compromised, I only have to delete one public key in authorized keys and generate a new one. That's still open to some attacks, but way less dangerous than simply allowing anyone from anywhere to log in. That's also better than allowing only a few IPs on port 22, because you'll never now where you will be and what IP your laptop will have when an emergency occurs.
- chmike 13y ago
  Fail2ban prevents brute force connection attempts. One can also chose a password resistent to brute force by using a long string. A psalm verse, or a sentence from some peoetry which is easy to remember. Or pick a password made of the first letter of each word of this long sentence.
  - regularfry 13y ago
    > A psalm verse, or a sentence from some peoetry which is easy to remember. I think you'd be astonished at how weak these are. That's part of the problem: it's hard, and not getting easier, to pick strong passwords.
- gambler 13y ago
  I have one on my desktop, one on my laptop and one on my mobile. If any get compromised, I only have to delete one public key in authorized keys and generate a new one. Personally, I still don't like SSH keys. Yes, they are "more secure" in the sense of preventing others from breaking into your servers. But they are less reliable in a sense that they increase your probability of being completely locked out when shit hits the fan. Laptop, desktop and mobile phone? If you can't imagine a situation where you will loose access to all three at once, you either live a very different lifestyle than I do or have a poor imagination. For me, the expected loss (i.e. probability * damage) of loosing access to an important server because of some fire of flood is far greater than the expected loss of someone guessing SSH port, my login, my password and then the root password.
  - oelmekki 13y ago
    Well, maybe you live in some place especially prone to natural catastrophes :) I live in France, and I certainly have lesser chances to loose all devices at once than to have a single one compromised.
spindritf 13y ago
> A secret key protected by password doesn't provide you more security. It does. You can encrypt the key and then you have two-factor authentication. You need to have the key and know the password to use it.
- chmike 13y ago
  I don't want to be picky but this isn't two factor authentication in its usual sense. Two factor authentication uses two independent means/media to authenticate. Protecting the private key with a password is required to protect it of beeing exposed when stolen. But if it's stolen then brute force password guessing is for free. Brute force attack against a login password can be detected and impaired, not with stolen private key.
  - marcosdumay 13y ago
    You must have the key, and know the password. Two factors.
    - e12e 13y ago
      It might have been true if it wasn't possible to get a copy of the plaintext key (eg: from ssh-agent). Actual two-factor authentication would be requiring proof of access to the secret key and a diffrent login password.

by chmike 13y ago

oelmekki 13y ago

Password authentication is prone to bruteforce. With public key auth, even if someone has your passphrase, he also needs the private key to break into your server. Indeed, there's always the risk to lose your private key. That's why it's useful to have several : I have one on my desktop, one on my laptop and one on my mobile. If any get compromised, I only have to delete one public key in authorized keys and generate a new one. That's still open to some attacks, but way less dangerous than simply allowing anyone from anywhere to log in. That's also better than allowing only a few IPs on port 22, because you'll never now where you will be and what IP your laptop will have when an emergency occurs.

chmike 13y ago
Fail2ban prevents brute force connection attempts. One can also chose a password resistent to brute force by using a long string. A psalm verse, or a sentence from some peoetry which is easy to remember. Or pick a password made of the first letter of each word of this long sentence.
- regularfry 13y ago
  > A psalm verse, or a sentence from some peoetry which is easy to remember. I think you'd be astonished at how weak these are. That's part of the problem: it's hard, and not getting easier, to pick strong passwords.
gambler 13y ago
I have one on my desktop, one on my laptop and one on my mobile. If any get compromised, I only have to delete one public key in authorized keys and generate a new one. Personally, I still don't like SSH keys. Yes, they are "more secure" in the sense of preventing others from breaking into your servers. But they are less reliable in a sense that they increase your probability of being completely locked out when shit hits the fan. Laptop, desktop and mobile phone? If you can't imagine a situation where you will loose access to all three at once, you either live a very different lifestyle than I do or have a poor imagination. For me, the expected loss (i.e. probability * damage) of loosing access to an important server because of some fire of flood is far greater than the expected loss of someone guessing SSH port, my login, my password and then the root password.
- oelmekki 13y ago
  Well, maybe you live in some place especially prone to natural catastrophes :) I live in France, and I certainly have lesser chances to loose all devices at once than to have a single one compromised.

spindritf 13y ago

> A secret key protected by password doesn't provide you more security. It does. You can encrypt the key and then you have two-factor authentication. You need to have the key and know the password to use it.

chmike 13y ago
I don't want to be picky but this isn't two factor authentication in its usual sense. Two factor authentication uses two independent means/media to authenticate. Protecting the private key with a password is required to protect it of beeing exposed when stolen. But if it's stolen then brute force password guessing is for free. Brute force attack against a login password can be detected and impaired, not with stolen private key.
- marcosdumay 13y ago
  You must have the key, and know the password. Two factors.
  - e12e 13y ago
    It might have been true if it wasn't possible to get a copy of the plaintext key (eg: from ssh-agent). Actual two-factor authentication would be requiring proof of access to the secret key and a diffrent login password.