Archived thread 1020770 from Recurring Discussions. Markdown source: Recurring_Discussions/thread_1020770_sudo_timeout.md
I've done this by mistake, i'm showing this so that the developers can fix the bug.
Type in terminal:
gksudo something (i typed nautlius instead of nautilus)
after that type
gksudo nautilus
or gksudo synaptic
it will open it without asking root password. Bad guys can just erase my hard disk this way...
P.S. I've done it by mistake, i have not tried to hack Ubuntu. Please don't give me any penalty points. :)
Kinetic_lord said: I've done this by mistake, i'm showing this so that the developers can fix the bug.
Type in terminal:
gksudo something (i typed nautlius instead of nautilus)
after that type
gksudo nautilus
or gksudo synaptic
it will open it without asking root password. Bad guys can just erase my hard disk this way...
P.S. I've done it by mistake, i have not tried to hack Ubuntu. Please don't give me any penalty points. :)
That's called "sudo timeout".
It's set to 15 minutes by default on Ubuntu, what is very, very unsafe.
If you want to disable that:
http://linuxowns.wordpress.com/2008/10/21/change-gksudo-timeout/
After you type a command that requires authentication, the authorization remains for a short time (15 minutes I think). It's no bug.
Not a bug. Not a hack.
sudo and graphical sudo are designed to work this way, see above for how to change the configuration.
You're alright!
It's not a bug it's by design!
You are doing it all from the same terminal, thereofre once you've entered the password for that terminal it remembers it for next time. This allows you to run a series of commands without having to enter the password again.
If you close the terminal and then open a fresh one you'll need to enter the password again.
I can't remember but there might even be a time limit on the password as well!
Ubuntu doesn't have bugs! Those are just undocumented features :P
artir said: Ubuntu doesn't have bugs! Those are just undocumented features :P
+1, made me lol
Well... not bug, i couldn't find the right word :D. Well, the point is that you can access applications wtih no root pass :D. (and that's not good) :D
artir said: Ubuntu doesn't have bugs! Those are just undocumented features :P
Right :D!
I agree it's unsafe. However, even with the timeout, you still have people griping that they have to type in their password all the time.
lykwydchykyn said: I agree it's unsafe. However, even with the timeout, you still have people griping that they have to type in their password all the time.
The system is perfectly flawed...
I think sudo in itself is a security risk, people don't even have to know the root password, they just need to know your regular username's password, and they can do anything.
sudo is an extremely powerful tool, esp. in situations where multiple users have access to a machine/server/system. You can control in a lot of detail what users can and cannot do with the sudo command. In Ubuntu it defaults to the original user of the system having full admin privileges - this is part of Ubuntu's security model so that users don't have to setup a root password. Having a root password (and also having to remember that password) is more of a security risk to a system than a user having sudo. Not having to enter a password *every single time* you run sudo, after running it once, is for convenience. It is expected that to use sudo and punch in your password, you take that extra second to realize that what you are doing is an administrative task. sudo can be configured so that you have to enter a password every time, but it would be a major pain to have to deal with for a lot of people. It's a tradeoff of convenience and security. It's still your job to protect your computer and your password - if you're in an environment where others have access to your machine, then lock the screen when you step afk.
Kinetic_lord said: Well... not bug, i couldn't find the right word :D. Well, the point is that you can access applications wtih no root pass :D. (and that's not good) :D
No, you can't access those applications without a root password. You have already entered your password once, and this authenticates you for the next 15 minutes. This behavior is easy to change, if you so wish, and is default for considered and valid reasons. It's not a flaw in the system.
This is nothing more than a misunderstanding of how sudo works.
lykwydchykyn said: I agree it's unsafe. However, even with the timeout, you still have people griping that they have to type in their password all the time.
Aye. Anyone giving instructions to people using sudo should be telling them to run ``` sudo -k
TWO said: Aye. Anyone giving instructions to people using sudo should be telling them to run ```
sudo -k
Too bad sudo -k doesn't work the way its documentation describes. Try opening 2 termnals, run a command with sudo in each, then issue sudo -k or sudo -K in one of them. The other will still allow sudo commands without password.
Even worse, run a gui program that requies a password, like synaptic. Regardless of if you use "sudo -k", for the next 15 minutes synaptic will start without a password.
In fact, you can even log out completely and log back in again and still not need a password for sudo within the timeout period.You can forcibly end the sudo timeout by typing "sudo -k"
lswb said: Too bad sudo -k doesn't work the way its documentation describes. Try opening 2 termnals, run a command with sudo in each, then issue sudo -k or sudo -K in one of them. The other will still allow sudo commands without password.
Even worse, run a gui program that requies a password, like synaptic. Regardless of if you use "sudo -k", for the next 15 minutes synaptic will start without a password.
In fact, you can even log out completely and log back in again and still not need a password for sudo within the timeout period.
macogw said: You can forcibly end the sudo timeout by typing "sudo -k"
What lswb says is true, though. sudo -k will not close the timeout period for another shell session. At least in 8.10.
lswb said: Too bad sudo -k doesn't work the way its documentation describes. Try opening 2 termnals, run a command with sudo in each, then issue sudo -k or sudo -K in one of them. The other will still allow sudo commands without password.
I don't see how that contradicts the documentation, you are running two different shells/prompts, sudo in the first one, won't set the timestamp for the second terminal, you will still be asked for the password. sudo -k in one of the terminals will in the same way not affect the other terminal. This is even true for two bash prompts running through screen.
red_Marvin said: I don't see how that contradicts the documentation, you are running two different shells/prompts, sudo in the first one, won't set the timestamp for the second terminal, you will still be asked for the password.
sudo -k in one of the terminals will in the same way not affect the other terminal. This is even true for two bash prompts running through screen.
Well, here is what the man page for sudo says about -K and -k. I've emphasized 2 things that I feel don't agree with the actual behavior of sudo.
-K The -K (sure kill) option is like -k except that it removes the user’s timestamp entirely. Like -k, this option does not require a password.
-k The -k (kill) option to sudo invalidates the user’s timestamp by setting the time on it to the Epoch. [B]The next time sudo is run a password will be required. [/B] This option does not require a password and was added to [B]allow a user to revoke sudo permissions from a .logout file.[/B]
I don't see anything in there about "unless you happen to have another shell open somewhere" and the logout part is just flat out wrong, IMHO the correct behavior for sudo -k or -K would be to require a password the next time it is invoked, regardless of from which shell session or tty. If -k or -K doesn't do this by design, then it should be explained, and an option that DOES have this behaviour really needs to be added.
Hmm, yes I guess that is a matter of interpretation, I compare it with say, the bash history, that also isn't shared between terminals. But since this confusion *can* arise it seems that there should be a clarification made.