Re: Linux auto idle logout & vlock possible security problem

[jimd () STARSHINE ORG (Jim Dennis)]

> There's a possible security problem using auto idle logout programs and vt
> lockers.
> Try the following:
> get the pid of your shell,
> (sleep 10s ; kill -HUP <pid-of-your-shell) &
> vlock -a
>
> after vlock -a, you can't change the virtual console on a Linux terminal.
> But if you log in, start vlock -a, enter your password you can change
> vt...
>
> The same happens when an auto idle logout program logs you off. The vlock
> (maybe lockvt also)  program doesn't terminate itself after a SIGHUP,
> which is ok, but after this, anyone can log in, start vlock -a, enters
> his/her password, and get full access to the console.
>
> Possible solutions:
> - don't use vlock/lockvt
> - don't use auto idle logout program
> - as root, never leave your terminal. log off.
> if you want to leave, use screen, detach it and log out.

        Are there any known security issues with 'screen'?
        I personally suggest patching the sources to force
        it to put its socket (unix domain) in ~/tmp/.screen
        --- so users can make sure that the directory has
        appropriate permissions.


        Has anyone vette'd the code?

--
Jim Dennis  (800) 938-4078              consulting () starshine org
Proprietor, Starshine Technical Services:  http://www.starshine.org