Apache safe config with mod_proxy

apache2.conf

# simple http authentification with htpasswd
<Directory /var/www>
   Options Indexes FollowSymLinks MultiViews
   AllowOverride All
   Order allow,deny
   allow from all
   AuthName "Restricted"
   AuthGroupFile /dev/null
   AuthType Basic
   AuthBasicProvider file
   AuthUserFile /etc/users/.htpasswd
   Require user $USER_NAME
</Directory>

# deny usage of proxy, should be already by default in most apache2 installations
<Proxy *>
  Order deny,allow
  Deny from all
</Proxy>

ProxyPass         /jenkins  http://localhost:8081/jenkins
ProxyPassReverse  /jenkins  http://localhost:8081/jenkins

# IMPORTANT: proxy cannot be used as open proxy
ProxyRequests     Off

# controlling access to specific proxy redirection
<Proxy http://localhost:8081/*>
    Order deny,allow
    Allow from all
    AuthType Basic
    AuthName "Password Required"
    AuthUserFile /etc/users/.htpasswd
    Require user $USER_NAME
</Proxy>