Cyber Security Lab 1
Due
In two parts, Jan 26 and Feb 2 in class.
Goal
Use techniques for least privilege and multiple users to solve similar problems in
Windows XP and Linux.
Scenario
You have been contracted by YoYoDyne, Inc. to implement a data management package.
They are not certain about which platform they want to build on, so they want to better
understand the security mechanisms provided by Windows and Linux. They hired you to
prototype the solution on both Windows and Linux.
Their application needs to perform some privileged operations (to access very secret
files) regardless of who invokes it. After this initial privileged operation, the program
must read and write files that are only accessible to the invoking user.
Windows Requirements
On Windows, you could implement this as a server will be running as a service. It will
listen on a named pipe for client requests. The client will pass in the full path name of
the file it wants the server to access. The server will try to access the file as itself, and
then as the user. The server should log the results of these access attempts to a log file.
Assuming it is successful; the server will return the first 512 bytes of the file. Instead of
actually installing a service, you can use the “runas” utility to invoke the server and client
as different users for testing.
Run your Server as a member of the administrative group. The program should examine
and disable all unnecessary privileges at the start of the program. It should log the
privileges and their original states to a log file.
Linux Requirements
On Linux, you can use setuid implement a program that is initiated as root user. Then
use the libcap/setcap calls to drop unnecessary privileges. Finally use the setresuid call to
change the user ID to the invoking user. This program should perform the same
operations as the windows programs to fetch files for the invoking user. The program
should implement similar logging as identified in the Windows requirements. Since the
program is invoked directly, the requested file can be passed through the command line
or standard I/O rather than through a pipe.
Alternate Requirements
For this scenario, a modular solution as demonstrated in the qmail design could also be
applied. You may chose to use the modular solution for either Linux or Windows. But
Cyber Security ‘06 Page 1 Lab 1
