Re: use of base image / delta image for automated recovery from attacks

From: Brian Hatch (secprogat_private)
Date: Thu Sep 05 2002 - 11:33:21 PDT

  • Next message: Crispin Cowan: "Re: FW: use of base image / delta image for automated recovery from attacks"

    > Simple approxmation to this: make /usr a separate partion, and mount it 
    > read-only:
    > 
    >    * The good news: attackers that want to trojan your software have to
    >      reboot, at least.
    >    * The bad news: administrators that want to update your software
    >      have to reboot, at least.
    
    No reboot is required, you just need to remount it:
    
    	# mount -o remount,rw /usr
    
    This requires root access, but presumably /usr is safe from non-root
    users anyway.
    
    Only way to disable this is to have the kernel compiled with something
    that compartmentalizes capabilities (LIDS/etc on Linux for example) or to
    remove CAP_SYS_ADMIN with lcap, which would definately require a reboot,
    and possibly break some other functionatily to boot.  (Pun intended.  My
    apologies.)
    
    --
    Brian Hatch                  "Are you expected?"
       Systems and               "No.  Dreaded."
       Security Engineer
    www.hackinglinuxexposed.com
    
    Every message PGP signed
    
    
    



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