Why are some folders world-writeable?

Solution Verified - Updated -


  • Red Hat Enterprise Linux 3,4,5,6,7


These folders have world writeable permissions. Why?
- /proc
- /dev
- /tmp (and it's contents)
- /var/tmp



These first two folders are part of a pseudo file system that is used to communicate with the kernel. In order for user space to use the interfaces in /proc and /dev, they need to be writable by others. Changing these permissions is not recommend and if the permissions of these files are modified, they will not persist across reboots as these folders are not backed on disk.



The purpose of these three folders is that of a temporary work space, with the understanding that things written here my be erased at any time. As such, anyone can read/write to these folders, and any process that does is responsible for the permissions used.

Root Cause

  • Normal operation of operating system

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