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Thread: sudo timeout: security risk?

  1. #1
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    Exclamation sudo timeout: security risk?

    I'm talking about the 15 minute 'remembrance' - or whatever you call it - of course. Don't you think that the fact that after you run, say, sudo vim /etc/fstab to add your NFS share on your NAS to the fstab, you (or anyone else) could then just run any old command and brick your whole system or anything root has read/write access to (including remote filesystems), within a 15 minute window?

    Also, I might have forgotten this, but can anyone enlighten me on how to turn this 'feature' off? Sorry to sound like a n00b, I ain't.
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  2. #2
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    Re: sudo: security risk?

    is it 15 minutes now? the default is 5.

    anyways, i change mine to 1 minute.
    Last edited by kerry_s; October 1st, 2009 at 11:00 AM.

  3. #3
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    Re: sudo: security risk?

    Anyway, to completely disable it, set the timestamp_timeout in /etc/sudoers to 0 (see 'man sudoers' for more details).

  4. #4
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    Re: sudo: security risk?

    Quote Originally Posted by fela View Post
    I'm talking about the 15 minute 'remembrance' - or whatever you call it - of course. Don't you think that the fact that after you run, say, sudo vim /etc/fstab to add your NFS share on your NAS to the fstab, you (or anyone else) could then just run any old command and brick your whole system or anything root has read/write access to (including remote filesystems), within a 15 minute window?

    Also, I might have forgotten this, but can anyone enlighten me on how to turn this 'feature' off? Sorry to sound like a n00b, I ain't.
    I think they'd have to have access to your pc...how would they open a session? Nevertheless I usually set my
    Defaults:username timestamp_timeout=2
    It says 2 minutes but I usually do 2 or less. This means Sudo requires my password again after 2 minutes. As someone else said you can set it to 0 to make it require the password every time. The sudoers file is in /etc/sudoers.

  5. #5
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    Re: sudo timeout: security risk?

    Well, as another thread so proudly states, "Physical Access is Root Access" so...
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  6. #6
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    Re: sudo timeout: security risk?

    I leave mine at the default 5 minutes; generally what ever I'm doing that requires escalated priv's will take 6 minutes to accomplish anyway

  7. #7
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    Re: sudo timeout: security risk?

    As another poster said, physical access is root access, and there's a thread about that already.

    If the goal is just to brick the computer, you don't even need root access. The first two possibilities that come to mind are

    1. the old bash one-line fork bomb : you only need a terminal and all of ten seconds to remember the command and type it
    2. a hammer
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  8. #8
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    Re: sudo timeout: security risk?

    unless there is physical access to the computer or the account you used to sudo has been compromised already then there is nothing to worry about.

    this is basically asking 'if my security has already been compromised, is that a security risk?'

    well the answer to this is surprisingly no. its not a risk anymore, it is a certainty as it has already happened.

  9. #9
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    Re: sudo timeout: security risk?

    Ok, thanks for the replies guys. I've changed my limit to 1 minute now (apt-get installs usually take more than 1 minute, most other administritive things are the same).

    And the reason I thought it was a security risk, is that I thought the point of sudo was to elevate permissions temporarily, so that you know when you can brick your computer but most of the time you can't.

    But with the 'remembrance' bug (I call it a bug not a feature ), surely all that goes out of the window? Depending on the limit you've set (or haven't remembered to reset), you can brick your computer for a whole 5 (or 15, I thought) minutes after you've allowed yourself to brick your computer so-called temporarily! Surely that goes against the point of sudo, and you might aswell just su root instead?
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  10. #10
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    Re: sudo timeout: security risk?

    Quote Originally Posted by fela View Post
    But with the 'remembrance' bug (I call it a bug not a feature ), surely all that goes out of the window? Depending on the limit you've set (or haven't remembered to reset), you can brick your computer for a whole 5 (or 15, I thought) minutes after you've allowed yourself to brick your computer so-called temporarily! Surely that goes against the point of sudo, and you might aswell just su root instead?
    You still have to type sudo, which serves as a reminder that you're doing dangerous things. Again, it is possible to brick a computer with non-administrative commands.

    Enabling a root account is not recommended for security reasons (mostly to double the time necessary to brute-force one's way through your login/password).
    This is the first age that's paid much attention to the future, which is a little ironic since we may not have one.
    -- Arthur C. Clarke

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