Differences

This shows you the differences between two versions of the page.

--- software:encryption [2011/12/24 13:05]
cyril [Boot security]
+++ software:encryption [2015/07/30 21:05]
cyril [Good passwords]
@@ Line 12: / Line 12: @@
 Ensure that your computer remains locked when unattended. Ask password for login, systematically manually lock it when you leave it, set up your screen saver to automatically lock it after a few minute of user inactivity in case you forget, and configure it to be locked when it resumes from sleeping.
+==== Good passwords ====
+Not only your encryption password must be robust, but also your user and root session passwords (I mean passphrases!), especially if you need to run an ssh daemon. You must store them in a secure manner (I mean only in your head), and be cautious when you enter them.
+Also if you are more worried about the security of your data than of your system, you may want to avoid asking your password for sudo. If someone get access to your machine unlocked, then your data are compromised, and he will be able to watch them or copy them even without root access (except if you have taken a lot of care that he could not mount any external storage or access to network without root access, but it would be a pain to use this machine then). On the other hand, the more you have to enter your password, the more you take risks of someone eyedropping it, so it is better to only ask for passwords when they are really necessary. All about compromise!
+And avoid connecting to your machine from not very secure machines (eg prefer scp-ing from your machine to the remote machine than the contrary).
 ==== When to mount ====
@@ Line 63: / Line 70: @@
   * set a BIOS password that will be needed to boot the machine. Same effect as before, although you have to enter a password at boot every time. You may however be able to bypass the password on reboot, and set a common password with the hdd that will be prompted only once.
   * set a hard drive password that will be needed to use the hard drive at boot. It can be defeated by a qualified attacker (such as a data recovery company, or maybe some software but probably not without erasing the data if max security mode was selected), you have to enter the password at each boot, and if you forget it the data are lost (or the drive if you don't have the right recovery software), but it is a good way to prevent your system from being compromised.
-  * always leave it unattended in sleep mode rather than shut down, so that you can detect that is has been rebooted and may be compromised (but it is more problematic for the keys in RAM).
+  * if you leave it unattended in sleep mode rather than shut down, you can detect that is has been rebooted and may be compromised (but it is more problematic for cold boot attacks keys in RAM).
+  * black list the firewire modules to prevent cold boot DMA attacks
 ==== The system and the environment ====