 .    ,    -
 ,       -
.         ,  
.        , -
     ,       -
 su   root,  ,     
,        . -
     ,       , -
       .

       :

1.       (.  "-
 "    )   .

2.         (. -
 "  "    ), 
     root:      
.

3.         su ("substitute
user"   ),       
 .    
  "su:    ".

4.     sudo     -
        -
  .  sudo   /etc/sudoers, -
    .  
.  man-  sudo.

 setuid,  root,  .  
setuid,  root,  ,     root, 
  ,      -
.          . 
setuid      ,   -
   nosuid (.  " "  12).

5.      setuid ( 
, .  "  setuid  setgid"  6). 
setuid         , 
 .        
 ,    root,  setuid.  
  ,  root    setuid,
     root. To     ,
   root,        -
.    .   
      ,  
    .  setuid,  root, -
           -
     .   setuid,  root:

passwd, at  crontab.      ,  -
      setuid:

 11.  :                     395