Mastering Linux Security and Hardening - Second Edition

Hands-on lab – setting security-related extended file attributes

For this lab, you'll need to create a perm_demo.txt file with some text of your choice. You'll set the i and a attributes and view the results. Let's get started:

1. Using your preferred text editor, create the perm_demo.txt file with a line of text.
2. View the extended attributes of the file:

lsattr perm_demo.txt

3. Add the a attribute:

sudo chattr +a perm_demo.txtlsattr perm_demo.txt

4. Try to overwrite and delete the file:

echo "I want to overwrite this file." > perm_demo.txtsudo echo "I want to overwrite this file." > perm_demo.txtrm perm_demo.txtsudo rm perm_demo.txt

5. Now, append something to the file:

echo "I want to append this line to the end of the file." >> perm_demo.txt ...