Opportunity:  In the context of computing a concept called chroot in the unix context,

              usually modelled or labled ...called safe zone ...where programs executing
              in the context can exploit flaws like buffer overflow's etc ...which (chroot)
              limit access to programs ...its definition being "A chroot on Unix operating systems
              is an operation that changes the apparent disk root directory for the current running
              process and its children"

              understanding from the above ...chroot as a concept can be exploited on the client side ...for
              restricting malice's percievable from 'Internet cache' ....in the context of a  web-browser,
              directories or folders hosting ....email's (on client's as well as email-servers)
              ...other download attachments ...comming from or recieved from anything over the network ideally.

              similarly the below concept can

              The sticky bit is an access-right flag that can be assigned to files and directories on Unix systems
              be enforced or exploited upon such folders or containers.

              viz. above solve's or reduces the  percievable risks from virus ...and should
                   be envincible.
             

Note: The above problem statement having been encountered in various scenarios
      and detailed in various 'Proof of concepts' as mentioned in 
      
       http://uk.geocities.com/ravivenkatus/projects.pdf
       http://ravishankarkv.tripod.com/projects.pdf
        ....apply appropriate
      'use-case' modeling, rationalize and arrive at a workable and feasible 
       solution both commercially and techinically viable.

             

           


 
             