Execute root binaries as user

From wiki.network-crawler.de

build@linux-builder:~$ sudo chmod 4755 /sbin/ifconfig 
build@linux-builder:~$ ls -la /sbin/ifconfig 
-rwsr-xr-x 1 root root 61736 Mar 16  2009 /sbin/ifconfig

now it is possible for normal usere to execute ifconfig with root
permissions:

build@linux-builder:~$ /sbin/ifconfig eth1 up