Exactprep SSCP Questions

The reference monitor concept is an abstract machine that ensures that all subjects have the necessary access rights before accessing objects. Therefore, the kernel will mediates all accesses to objects by subjects and will do so by validating through the reference monitor concept.

The kernel does not decide whether or not the access will be granted, it will be the Reference Monitor which is a subset of the kernel that will say YES or NO.

All access requests will be intercepted by the Kernel, validated through the reference monitor, and then access will either be denied or granted according to the request and the subject privileges within the system.

1. The reference monitor must be small enough to be full tested and valided

2. The Kernel must MEDIATE all access request from subjects to objects

3. The processes implementing the reference monitor must be protected

4. The reference monitor must be tamperproof

The following answers are incorrect:

The security kernel is the mechanism that actually enforces the rules of the reference monitor concept.

The other answers are distractors.

Shon Harris, All In One, 5th Edition, Security Architecture and Design, Page 330

also see

http://en.wikipedia.org/wiki/Reference_monitor

This is the most serious risk of inadequate systems development life cycle methodolgy.

The following answers are incorrect because :

The project will be completed late is incorrect as it is not most devastating as the above answer.

The project will exceed the cost estimates is also incorrect when compared to the above correct answer.

The project will be incompatible with existing systems is also incorrect when compared to the above correct answer.

Debugging provides the basis for the programmer to correct the logic errors in a program under development before it goes into production.

Source: Information Systems Audit and Control Association, Certified Information Systems Auditor 2002 review manual, chapter 6: Business Application System Development, Acquisition, Implementation and Maintenance (page 298).

More and more organizations are setting up their own internal PKIs. When these independent PKIs need to interconnect to allow for secure communication to take place (either between departments or different companies), there must be a way for the two root CAs to trust each other.

These two CAs do not have a CA above them they can both trust, so they must carry out cross certification. A cross certification is the process undertaken by CAs to establish a trust relationship in which they rely upon each other's digital certificates and public keys as if they had issued them themselves.

When this is set up, a CA for one company can validate digital certificates from the other company and vice versa.

Reference(s) used for this question:

For more information and illustration on Cross certification: http://www.microsoft.com/technet/prodtechnol/windowsserver2003/technologies/security/ws03qswp.mspx http://www.entrust.com/resources/pdf/cross_certification.pdf

also see:

Shon Harris, CISSP All in one book, 4th Edition, Page 727

and

RFC 2459: Internet X.509 Public Key Infrastructure Certificate and CRL Profile; FORD, Warwick & BAUM, Michael S., Secure Electronic Commerce: Building the Infrastructure for Digital Signatures and Encryption (2nd Edition), 2000, Prentice Hall PTR, Page 254.