System Security Certified Practitioner (SSCP)

The Rijndael algorithm, chosen as the Advanced Encryption Standard (AES) to replace DES, can be categorized as an iterated block cipher with a variable block length and key length that can be independently chosen as 128, 192 or 256 bits.

Below you have a summary of the differences between AES and Rijndael.

AES is the advanced encryption standard defined by FIPS 197. It is implemented differently than Rijndael:

FIPS-197 specifies that the block size must always be 128 bits in AES, and that the key size may be either 128, 192, or 256 bits. Therefore AES-128, AES-192, and AES-256 are actually:

Key Size (bits) Number of rounds

Block Size (bits)

AES-128
128 10 Rounds
AES-192

192 12 Rounds
AES-256

256 14 Rounds
Some book will say "up to 9 rounds will be done with a 128 bits keys". Really it is 10 rounds because you must include round zero which is the first round. By contrast, the Rijndael specification per se is specified with block and key sizes that may be any multiple of 32 bits, both with a minimum of 128 and a maximum of 256 bits.

Reference(s) used for this question:

KRUTZ, Ronald L. & VINES, Russel D., The CISSP Prep Guide: Mastering the Ten Domains of Computer Security, John Wiley & Sons, 2001, Chapter 4: Cryptography (page 153).

and

FIPS 197

and

https://en.wikipedia.org/wiki/Advanced_Encryption_Standard

Once the merchant server has been authenticated by the browser client, the browser generates a master secret that is to be shared only between the server and client. This secret serves as a seed to generate the session (private) keys. The master secret is then encrypted with the merchant's public key and sent to the server. The fact that the master secret is generated by the client's browser provides the client assurance that the server is not reusing keys that would have been used in a previous session with another client.

Source: ANDRESS, Mandy, Exam Cram CISSP, Coriolis, 2001, Chapter 6: Cryptography (page 112).

Also: HARRIS, Shon, All-In-One CISSP Certification Exam Guide, McGraw-Hill/Osborne, 2001, page 569.

TACACS+ is a proprietary Cisco enhancement to TACACS and is more robust than RADIUS. PAP is not a remote access authentication system but a remote node security protocol.

Source: KRUTZ, Ronald L. & VINES, Russel D., The CISSP Prep Guide: Mastering the Ten Domains of Computer Security, John Wiley & Sons, 2001, Chapter 3: Telecommunications and Network Security (page
122).

Evaluation as a general term is described as the process of independently assessing a system against a standard of comparison, such as evaluation criteria. Evaluation criterias are defined as a benchmark, standard, or yardstick against which accomplishment, conformance, performance, and suitability of an individual, hardware, software, product, or plan, as well as of risk-reward ratio is measured.

What is computer security evaluation?

Computer security evaluation is the detailed examination and testing of the security features of an IT system or product to ensure that they work correctly and effectively and do not show any logical vulnerabilities. The Security Target determines the scope of the evaluation. It includes a claimed level of Assurance that determines how rigorous the evaluation is.

Criteria

Criteria are the "standards" against which security evaluation is carried out. They define several degrees of rigour for the testing and the levels of assurance that each confers. They also define the formal requirements needed for a product (or system) to meet each Assurance level.

TCSEC

The US Department of Defense published the first criteria in 1983 as the Trusted Computer Security Evaluation Criteria (TCSEC), more popularly known as the "Orange Book". The current issue is dated 1985. The US Federal Criteria were drafted in the early 1990s as a possible replacement but were never formally adopted.

ITSEC

During the 1980s, the United Kingdom, Germany, France and the Netherlands produced versions of their own national criteria. These were harmonised and published as the Information Technology Security Evaluation Criteria (ITSEC). The current issue, Version 1.2, was published by the European Commission in June 1991. In September 1993, it was followed by the IT Security Evaluation Manual (ITSEM) which specifies the methodology to be followed when carrying out ITSEC evaluations.

Common Criteria
The Common Criteria represents the outcome of international efforts to align and develop the existing European and North American criteria. The Common Criteria project harmonises ITSEC, CTCPEC (Canadian Criteria) and US Federal Criteria (FC) into the Common Criteria for Information Technology Security Evaluation (CC) for use in evaluating products and systems and for stating security requirements in a standardised way. Increasingly it is replacing national and regional criteria with a worldwide set accepted by the International Standards Organisation (ISO15408).

The following answer were not applicable:

Certification is the process of performing a comprehensive analysis of the security features and safeguards of a system to establish the extent to which the security requirements are satisfied. Shon Harris states in her book that Certification is the comprehensive technical evaluation of the security components and their compliance for the purpose of accreditation.

Wikipedia describes it as: Certification is a comprehensive evaluation of the technical and non-technical security controls (safeguards) of an information system to support the accreditation process that establishes the extent to which a particular design and implementation meets a set of specified security requirements

Accreditation is the official management decision to operate a system. Accreditation is the formal declaration by a senior agency official (Designated Accrediting Authority (DAA) or Principal Accrediting Authority (PAA)) that an information system is approved to operate at an acceptable level of risk, based on the implementation of an approved set of technical, managerial, and procedural security controls (safeguards).

Acceptance testing refers to user testing of a system before accepting delivery.

Reference(s) used for this question:

HARE, Chris, Security Architecture and Models, Area 6 CISSP Open Study Guide, January 2002.

and
https://en.wikipedia.org/wiki/Certification_and_Accreditation

and

http://www.businessdictionary.com/definition/evaluation-criteria.html
and

http://www.cesg.gov.uk/products_services/iacs/cc_and_itsec/secevalcriteria.shtml

A security kernel is responsible for enforcing a security policy. It is a strict implementation of a reference monitor mechanism. The architecture of a kernel operating system is typically layered, and the kernel should be at the lowest and most primitive level. It is a small portion of the operating system through which all references to information and all changes to authorizations must pass. In theory, the kernel implements access control and information flow control between implemented objects according to the security policy.

To be secure, the kernel must meet three basic conditions:

completeness (all accesses to information must go through the kernel), isolation (the kernel itself must be protected from any type of unauthorized access),

and verifiability (the kernel must be proven to meet design specifications).

The reference monitor, as noted previously, is an abstraction, but there may be a reference validator, which usually runs inside the security kernel and is responsible for performing security access checks on objects, manipulating privileges, and generating any resulting security audit messages.

A term associated with security kernels and the reference monitor is the trusted computing base (TCB).
The TCB is the portion of a computer system that contains all elements of the system responsible for supporting the security policy and the isolation of objects. The security capabilities of products for use in the TCB can be verified through various evaluation criteria, such as the earlier Trusted Computer System Evaluation Criteria (TCSEC) and the current Common Criteria standard.

Many of these security terms--reference monitor, security kernel, TCB--are defined loosely by vendors for purposes of marketing literature. Thus, it is necessary for security professionals to read the small print and between the lines to fully understand what the vendor is offering in regard to security features.

TIP FOR THE EXAM:

The terms Security Kernel and Reference monitor are synonymous but at different levels.

As it was explained by Diego: While the Reference monitor is the concept, the Security kernel is the implementation of such concept (via hardware, software and firmware means).

The two terms are the same thing, but on different levels: one is conceptual, one is "technical"

The following are incorrect answers:

Confidentiality, Integrity, and Availability

Policy, mechanism, and assurance

Isolation, layering, and abstraction

Reference(s) used for this question:

Hernandez CISSP, Steven (2012-12-21). Official (ISC)2 Guide to the CISSP CBK, Third Edition ((ISC)2 Press) (Kindle Locations 13858-13875). Auerbach Publications. Kindle Edition.

Some physical controls include fences, lights, locks, and facility construction materials. Some administrative controls include facility selection and construction, facility management, personnel controls, training, and emergency response and procedures.

From: HARRIS, Shon, All-In-One CISSP Certification Exam Guide, McGraw-Hill/Osborne, 3rd.
Ed., Chapter 6, page 403.

Commercial firewalls are a dime-a-dozen in todays world. Black firewall and whitewall are just distracters.

It is the art and science of encoding hidden messages in such a way that no one, apart from the sender and intended recipient, suspects the existence of the message or could claim there is a message.

It is a form of security through obscurity.

The word steganography is of Greek origin and means "concealed writing." It combines the Greek words steganos (), meaning "covered or protected," and graphei () meaning "writing."

The first recorded use of the term was in 1499 by Johannes Trithemius in his Steganographia, a treatise on cryptography and steganography, disguised as a book on magic. Generally, the hidden messages will appear to be (or be part of) something else: images, articles, shopping lists, or some other cover text. For example, the hidden message may be in invisible ink between the visible lines of a private letter.

The advantage of steganography over cryptography alone is that the intended secret message does not attract attention to itself as an object of scrutiny. Plainly visible encrypted messages, no matter how unbreakable, will arouse interest, and may in themselves be incriminating in countries where encryption is illegal. Thus, whereas cryptography is the practice of protecting the contents of a message alone, steganography is concerned with concealing the fact that a secret message is being sent, as well as concealing the contents of the message.

It is sometimes referred to as Hiding in Plain Sight. This image of trees blow contains in it another image of a cat using Steganography.

ADS Tree with Cat inside

This image below is hidden in the picture of the trees above:

Hidden Kitty

As explained here the image is hidden by removing all but the two least significant bits of each color component and subsequent normalization.

ABOUT MSF and LSF

One of the common method to perform steganography is by hiding bits within the Least Significant Bits of a media (LSB) or what is sometimes referred to as Slack Space. By modifying only the least significant bit, it is not possible to tell if there is an hidden message or not looking at the picture or the media. If you would change the Most Significant Bits (MSB) then it would be possible to view or detect the changes just by looking at the picture. A person can perceive only up to 6 bits of depth, bit that are changed past the first sixth bit of the color code would be undetectable to a human eye.

If we make use of a high quality digital picture, we could hide six bits of data within each of the pixel of the image. You have a color code for each pixel composed of a Red, Green, and Blue value. The color code is 3 sets of 8 bits each for each of the color. You could change the last two bit to hide your data. See below a color code for one pixel in binary format. The bits below are not real they are just example for illustration purpose:

RED GREEN BLUE

0101 0101 1100 1011 1110 0011

MSB LSB MSB LSB MSB LSB

Let's say that I would like to hide the letter A uppercase within the pixels of the picture. If we convert the letter "A" uppercase to a decimal value it would be number 65 within the ASCII table , in binary format the value 65 would translet to 01000001

You can break the 8 bits of character A uppercase in group of two bits as follow: 01 00 00 01

Using the pixel above we will hide those bits within the last two bits of each of the color as follow:

RED GREEN BLUE

0101 0101 1100 1000 1110 0000

MSB LSB MSB LSB MSB LSB

As you can see above, the last two bits of RED was already set to the proper value of 01, then we move to the GREEN value and we changed the last two bit from 11 to 00, and finally we changed the last two bits of blue to 00. One pixel allowed us to hide 6 bits of data. We would have to use another pixel to hide the remaining two bits.

The following answers are incorrect:

- ADS - Alternate Data Streams: This is almost correct but ADS is different from steganography in that ADS hides data in streams of communications or files while Steganography hides data in a single file.

- Encryption: This is almost correct but Steganography isn't exactly encryption as much as using space in a file to store another file.

- NTFS ADS: This is also almost correct in that you're hiding data where you have space to do so. NTFS, or New Technology File System common on Windows computers has a feature where you can hide files where they're not viewable under normal conditions. Tools are required to uncover the ADS-hidden files.

The following reference(s) was used to create this question:

The CCCure Security+ Holistic Tutorial at http://www.cccure.tv and

Steganography tool

and

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

In cryptography, a public key certificate (or identity certificate) is an electronic document which incorporates a digital signature to bind together a public key with an identity -- information such as the name of a person or an organization, their address, and so forth. The certificate can be used to verify that a public key belongs to an individual.

In a typical public key infrastructure (PKI) scheme, the signature will be of a certificate authority (CA). In a web of trust scheme, the signature is of either the user (a self-signed certificate) or other users ("endorsements"). In either case, the signatures on a certificate are attestations by the certificate signer that the identity information and the public key belong together.

In computer security, an authorization certificate (also known as an attribute certificate) is a digital document that describes a written permission from the issuer to use a service or a resource that the issuer controls or has access to use. The permission can be delegated.

Some people constantly confuse PKCs and ACs. An analogy may make the distinction clear. A PKC can be considered to be like a passport: it identifies the holder, tends to last for a long time, and should not be trivial to obtain. An AC is more like an entry visa: it is typically issued by a different authority and does not last for as long a time. As acquiring an entry visa typically requires presenting a passport, getting a visa can be a simpler process. A real life example of this can be found in the mobile software deployments by large service providers and are typically applied to platforms such as Microsoft Smartphone (and related), Symbian OS, J2ME, and others.

In each of these systems a mobile communications service provider may customize the mobile terminal client distribution (ie. the mobile phone operating system or application environment) to include one or more root certificates each associated with a set of capabilities or permissions such as "update firmware", "access address book", "use radio interface", and the most basic one, "install and execute". When a developer wishes to enable distribution and execution in one of these controlled environments they must acquire a certificate from an appropriate CA, typically a large commercial CA, and in the process they usually have their identity verified using out-of-band mechanisms such as a combination of phone call, validation of their legal entity through government and commercial databases, etc., similar to the high assurance SSL certificate vetting process, though often there are additional specific requirements imposed on would-be developers/publishers.

Once the identity has been validated they are issued an identity certificate they can use to sign their software; generally the software signed by the developer or publisher's identity certificate is not distributed
but rather it is submitted to processor to possibly test or profile the content before generating an authorization certificate which is unique to the particular software release. That certificate is then used with an ephemeral asymmetric key-pair to sign the software as the last step of preparation for distribution.
There are many advantages to separating the identity and authorization certificates especially relating to risk mitigation of new content being accepted into the system and key management as well as recovery from errant software which can be used as attack vectors.

References:
HARRIS, Shon, All-In-One CISSP Certification Exam Guide, 2001, McGraw-Hill/Osborne, page 540. (http://en.wikipedia.org/wiki/Attribute_certificate)
http://en.wikipedia.org/wiki/Public_key_certificate

Controlling access to information systems and associated networks is necessary for the preservation of their confidentiality, integrity and availability.

Source: KRUTZ, Ronald L. & VINES, Russel D., The CISSP Prep Guide: Mastering the Ten Domains of Computer Security, 2001, John Wiley & Sons, Page 31.