Mastering Linux Security and Hardening - Second Edition

Setting the i attribute

When a file has the i attribute set, the only thing you can do with it is view its contents. You can't change it, move it, delete it, rename it, or create hard links to it. Let's test this with the perm_demo.txt file:

[donnie@localhost ~]$ sudo chattr +i perm_demo.txt[donnie@localhost ~]$ lsattr perm_demo.txt----i----------- perm_demo.txt[donnie@localhost ~]$

Now for the fun part:

[donnie@localhost ~]$ sudo echo "I want to overwrite this file." > perm_demo.txt-bash: perm_demo.txt: Permission denied[donnie@localhost ~]$ echo "I want to append this to the end of the file." >> perm_demo.txt-bash: perm_demo.txt: Permission denied[donnie@localhost ~]$ sudo echo "I want to append this to the end of the file." >> perm_demo.txt ...