Applying proper directory permissions for your live Joomla websites is one important step in securing it from malicious users online.
Use below commands to recursively set permissions to files and directories. Joomla recommends 707 special permissions for the /images and /images/stories directories.
find . -type f -exec chmod 644 {} \;
find . -type d -exec chmod 755 {} \;
chmod 707 images
chmod 707 images/stories
chown apache:apache cache