How to Secure /tmp

This will cover securing /tmp /var/tmp and /dev/shm Secure /tmp: Step 1: Backup your /etc/fstab file Code: cp /etc/fstab /etc/fstab.bak Step 2: Make a 3GB file for /tmp parition and an ext3 filesystem for tmp: Code: dd if=/dev/zero of=/var/tempFS bs=1024 count=3072000 /sbin/mkfs.ext3 /var/tempFS *Change the count= to something higher if you need more space* Step 3: Create a backup copy of your current /tmp drive: Code: cp -Rpf /tmp /tmpbackup Step 4: Mount our new tmp parition and change permissions: Code: mount -o loop,noexec,nosuid,rw /var/tempFS /tmp chmod 1777 /tmp Step 5: Copy the old data: Code: cp -Rpf /tmpbackup/* /tmp/ * If your /tmp was empty earlier, you might get this error : cp: cannot stat `/tmp.bak/*’: No such file or directory Step 6: Edit /etc/fstab and add this: Code: nano -w /etc/fstab And ADD this line: Code: /var/tempFS /tmp ext3 loop,nosuid,noexec,rw 0 0 Step 7: Test your fstab entry: Code: mount -o remount /tmp Step 8: Verify that your /tmp mount is working: Code: df -h Should look something like this: Code: /var/tempFS 962M 18M 896M 2% /tmp Secure /var/tmp: Step 1: Use /tmp as /var/tmp. Code: mv /var/tmp /var/vartmp ln -s /tmp /var/tmp Step 2: Copy the old data back Code: cp /var/vartmp/* /tmp/ * If your /var/tmp was empty earlier, you might get this error : cp: cannot stat `/var/vartmp/*’: No such file or directory Secure /dev/shm: Step 1: Edit your /etc/fstab: Code: nano -w /etc/fstab Locate: Code: none /dev/shm tmpfs defaults,rw 0 0 Change it to: Code: none /dev/shm tmpfs defaults,nosuid,noexec,rw 0 0 Step 2: Remount /dev/shm: Code: mount -o remount /dev/shm You should restart services that uses /tmp partition