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Is #chmod o-w /usr safe?
Posted: Tue Oct 23, 2012 12:00 am
by Wiz Kid
I was trying to set up a VM in virtualbox and a forum said to run this command
But is it safe or should I undo it, because in the end it was not what solved the problem. I don't want to run an insecure box. All I know is that I gave write permissions to that folder, but I don't know if that is very unsafe to do?
And can someone please post the undo command as well, Thanks.
Re: Is #chmod o-w /usr safe?
Posted: Tue Oct 23, 2012 12:53 am
by bkidwell
So my /usr folder is owned by root:root with 755 permissions you likely have the same with that command. If you drop to / and run
look for /usr and it should say something like
drwxr-xr-x 11 root root 4096 Sep 26 09:38 usr
If not you can set it to that with this.
The "o" symobilizes the last three letters of the 10, meaning other people besides the OWNER,(in this case root) and GROUP (also root).
The "-w" means remove write privilages, but as far as I can tell, that is the default anyway. So it's likely that command did not change any thing.
However if it was a "+w" then it made the folder open to be added too and deleted from by any user.
Re: Is #chmod o-w /usr safe?
Posted: Tue Oct 23, 2012 1:52 am
by Wiz Kid
I found i used "-w" after I looked at the log so everything seems to check out. Here's the result. Thanks for your time, much appreciated.
Code: Select all
abc@pc ~ $ cd /
abc@pc / $ ls -l
total 104
drwxr-xr-x 2 root root 12288 Oct 20 19:49 bin
drwxr-xr-x 3 root root 4096 Oct 20 19:59 boot
drwxr-xr-x 15 root root 4280 Oct 22 23:53 dev
drwxr-xr-x 138 root root 12288 Oct 23 01:23 etc
drwxr-xr-x 3 root root 4096 Sep 12 21:22 home
lrwxrwxrwx 1 root root 32 Sep 12 21:24 initrd.img -> boot/initrd.img-3.2.0-23-generic
lrwxrwxrwx 1 root root 33 Sep 12 21:14 initrd.img.old -> /boot/initrd.img-3.2.0-23-generic
drwxr-xr-x 24 root root 4096 Oct 20 19:49 lib
drwxr-xr-x 2 root root 4096 Oct 20 19:49 lib64
drwx------ 2 root root 16384 Sep 12 21:13 lost+found
drwxr-xr-x 3 root root 4096 Oct 23 01:23 media
drwxr-xr-x 2 root root 4096 Apr 19 2012 mnt
drwxr-xr-x 7 root root 4096 Sep 13 02:06 opt
dr-xr-xr-x 158 root root 0 Oct 22 23:52 proc
drwx------ 13 root root 4096 Sep 13 02:01 root
drwxr-xr-x 24 root root 820 Oct 22 23:54 run
drwxr-xr-x 2 root root 4096 Oct 20 19:56 sbin
drwxr-xr-x 2 root root 4096 Mar 5 2012 selinux
drwxr-xr-x 2 root root 4096 Apr 23 2012 srv
drwxr-xr-x 13 root root 0 Oct 22 23:52 sys
drwxrwxrwt 15 root root 12288 Oct 23 01:17 tmp
drwxr-xr-x 10 root root 4096 Apr 23 2012 usr
drwxr-xr-x 12 root root 4096 Oct 22 23:49 var
lrwxrwxrwx 1 root root 29 Sep 12 21:24 vmlinuz -> boot/vmlinuz-3.2.0-23-generic