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If unencrypted, yes. Ideally your home dir is encrypted [so that only the user can unlock and use it]. (The truly paranoid will keep their private keys on an en

If unencrypted, yes. Ideally your home dir is encrypted [so that only the user can unlock and use it]. (The truly paranoid will keep their private keys on an encrypted thumbdrive and remove it from the machine after authenticating the key into their keychain) But most of the time when I see network home directories in a company, it's just flat files on an NFS or CIFS share, which is bonkers.

whyever 8y ago
> The truly paranoid will keep their private keys on an encrypted thumbdrive and remove it from the machine after authenticating the key into their keychain Does not necessarily help when the machine is compromised. Using one key per machine and storing it in the corresponding home directory seems safer to me.
- peterwwillis 8y ago
  If you compromise the machine, you can attack anything on that machine. If the keys are in the home dir on the network, you can attack the network. If the keys are in the home dir on unencrypted local disk, you can attack the disk. If the keys are in a user namespace, you can attack the user namespace (which includes processes and mounts). If the keys are in a thumbdrive and in a keyring, you can only attack two things: 1) the user namespace, 2) the thumbdrive's mounted contents while it is inserted _and unlocked_. This limits the scope of attacks. When the keys in the keyring expire ("-t life" option to ssh-agent), you can't even attack that.
oarsinsync 8y ago
> The truly paranoid will keep their private keys on an encrypted thumbdrive and remove it from the machine after authenticating the key into their keychain While the more secure organisations disable USB in the OS / BIOS and glue the ports shut to prevent anyone using them, to prevent against data loss by employee. Source: worked in two different organisations that literally glued the USB ports shut.
xxpor 8y ago
The truly paranoid will implement an SSH CA that will sign the key's cert for a limited length of time, using u2f or similar to authenticate the user at the time of signing.
- deleted 8y ago
  [deleted]

whyever 8y ago

> The truly paranoid will keep their private keys on an encrypted thumbdrive and remove it from the machine after authenticating the key into their keychain Does not necessarily help when the machine is compromised. Using one key per machine and storing it in the corresponding home directory seems safer to me.

peterwwillis 8y ago
If you compromise the machine, you can attack anything on that machine. If the keys are in the home dir on the network, you can attack the network. If the keys are in the home dir on unencrypted local disk, you can attack the disk. If the keys are in a user namespace, you can attack the user namespace (which includes processes and mounts). If the keys are in a thumbdrive and in a keyring, you can only attack two things: 1) the user namespace, 2) the thumbdrive's mounted contents while it is inserted _and unlocked_. This limits the scope of attacks. When the keys in the keyring expire ("-t life" option to ssh-agent), you can't even attack that.

oarsinsync 8y ago

> The truly paranoid will keep their private keys on an encrypted thumbdrive and remove it from the machine after authenticating the key into their keychain While the more secure organisations disable USB in the OS / BIOS and glue the ports shut to prevent anyone using them, to prevent against data loss by employee. Source: worked in two different organisations that literally glued the USB ports shut.

xxpor 8y ago

The truly paranoid will implement an SSH CA that will sign the key's cert for a limited length of time, using u2f or similar to authenticate the user at the time of signing.

deleted 8y ago
[deleted]