- (Topic 5)
Which of the following would best describe certificate path validation?
Correct Answer:
A
With the advent of public key cryptography (PKI), it is now possible to communicate securely with untrusted parties over the Internet without prior arrangement. One of the necessities arising from such communication is the ability to accurately verify someone's identity (i.e. whether the person you are communicating with is indeed the person who he/she claims to be). In order to be able to perform identity check for a given entity, there should be a fool-proof method of “binding” the entity's public key to its unique domain name (DN).
A X.509 digital certificate issued by a well known certificate authority (CA), like Verisign, Entrust, Thawte, etc., provides a way of positively identifying the entity by placing trust on the CA to have performed the necessary verifications. A X.509 certificate is a cryptographically sealed data object that contains the entity's unique DN, public key, serial number, validity period, and possibly other extensions.
The Windows Operating System offers a Certificate Viewer utility which allows you to double-click on any certificate and review its attributes in a human-readable format. For instance, the "General" tab in the Certificate Viewer Window (see below) shows who the certificate was issued to as well as the certificate's issuer, validation period and usage functions.
Certification Path graphic
Certification Path graphic
The “Certification Path” tab contains the hierarchy for the chain of certificates. It allows you to select the certificate issuer or a subordinate certificate and then click on “View Certificate” to open the certificate in the Certificate Viewer.
Each end-user certificate is signed by its issuer, a trusted CA, by taking a hash value (MD5 or SHA-1) of ASN.1 DER (Distinguished Encoding Rule) encoded object and then encrypting the resulting hash with the issuer’s private key (CA's Private Key) which is a digital signature. The encrypted data is stored in the “signatureValue” attribute of the entity’s (CA) public certificate.
Once the certificate is signed by the issuer, a party who wishes to communicate with this entity can then take the entity’s public certificate and find out who the issuer of the certificate is. Once the issuer’s of the certificate (CA) is identified, it would be possible to decrypt the value of the “signatureValue” attribute in the entity's certificate using the issuer’s public key to retrieve the hash value. This hash value will be compared with the independently calculated hash on the entity's certificate. If the two hash values match, then the information contained within the certificate must not have been altered and, therefore, one must trust that the CA has done enough background check to ensure that all details in the entity’s certificate are accurate.
The process of cryptographically checking the signatures of all certificates in the certificate chain is called “key chaining”. An additional check that is essential to key chaining is verifying that the value of the "subjectKeyIdentifier” extension in one certificate matches the same in the subsequent certificate.
Similarly, the process of comparing the subject field of the issuer certificate to the issuer field of the subordinate certificate is called “name chaining”. In this process, these values must match for each pair of adjacent certificates in the certification path in order to guarantee that the path represents unbroken chain of entities relating directly to one another and that it has no missing links.
The two steps above are the steps to validate the Certification Path by ensuring the validity of all certificates of the certificate chain to the root certificate as described in the two paragraphs above.
Reference(s) used for this question:
FORD, Warwick & BAUM, Michael S., Secure Electronic Commerce: Building the Infrastructure for Digital Signatures and Encryption (2nd Edition), 2000, Prentice Hall PTR, Page 262.
and
https://www.tibcommunity.com/docs/DOC-2197
- (Topic 2)
Which of the following choices describe a condition when RAM and Secondary storage are
used together?
Correct Answer:
C
Virtual storage a service provided by the operating system where it uses a combination of RAM and disk storage to simulate a much larger address space than is actually present. Infrequently used portions of memory are paged out by being written to secondary storage and paged back in when required by a running program.
Most OS’s have the ability to simulate having more main memory than is physically available in the system. This is done by storing part of the data on secondary storage, such as a disk. This can be considered a virtual page. If the data requested by the system is not currently in main memory, a page fault is taken. This condition triggers the OS handler. If the virtual address is a valid one, the OS will locate the physical page, put the right information in that page, update the translation table, and then try the request again. Some other page might be swapped out to make room. Each process may have its own separate virtual address space along with its own mappings and protections.
The following are incorrect answers:
Primary storage is incorrect. Primary storage refers to the combination of RAM, cache and the processor registers. Primary Storage The data waits for processing by the processors, it sits in a staging area called primary storage. Whether implemented as memory, cache, or registers (part of the CPU), and regardless of its location, primary storage stores data that has a high probability of being requested by the CPU, so it is usually faster than long-term, secondary storage. The location where data is stored is denoted by its physical memory address. This memory register identifier remains constant and is independent of the value stored there. Some examples of primary storage devices include random-access memory (RAM), synchronous dynamic random-access memory (SDRAM), and read-only memory (ROM). RAM is volatile, that is, when the system shuts down, it flushes the data in RAM although recent research has shown that data may still be retrievable. Contrast this
Secondary storage is incorrect. Secondary storage holds data not currently being used by the CPU and is used when data must be stored for an extended period of time using high- capacity, nonvolatile storage. Secondary storage includes disk, floppies, CD's, tape, etc. While secondary storage includes basically anything different from primary storage, virtual memory's use of secondary storage is usually confined to high-speed disk storage.
Real storage is incorrect. Real storage is another word for primary storage and distinguishes physical memory from virtual memory.
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 17164-17171). Auerbach Publications. Kindle Edition.
Hernandez CISSP, Steven (2012-12-21). Official (ISC)2 Guide to the CISSP CBK, Third Edition ((ISC)2 Press) (Kindle Locations 17196-17201). Auerbach Publications. Kindle Edition.
Hernandez CISSP, Steven (2012-12-21). Official (ISC)2 Guide to the CISSP CBK, Third Edition ((ISC)2 Press) (Kindle Locations 17186-17187). Auerbach Publications. Kindle Edition.
- (Topic 1)
Which of the following is the LEAST user accepted biometric device?
Correct Answer:
C
The biometric device that is least user accepted is the retina scan, where a system scans the blood-vessel pattern on the backside of the eyeball. When using this device, an individual has to place their eye up to a device, and may require a puff of air to be blown into the eye. The iris scan only needs for an individual to glance at a camera that could be placed above a door.
Source: HARRIS, Shon, All-In-One CISSP Certification Exam Guide, McGraw- Hill/Osborne, 2002, Chapter 4: Access Control (page 131).
- (Topic 5)
In which phase of Internet Key Exchange (IKE) protocol is peer authentication performed?
Correct Answer:
B
The Internet Key Exchange (IKE) protocol is a key management protocol standard that is used in conjunction with the IPSec standard. IKE enhances IPSec by providing additional features, flexibility, and ease of configuration for the IPSec standard. IPSec can however, be configured without IKE by manually configuring the gateways communicating with each other for example.
A security association (SA) is a relationship between two or more entities that describes how the entities will use security services to communicate securely.
In phase 1 of this process, IKE creates an authenticated, secure channel between the two IKE peers, called the IKE security association. The Diffie-Hellman key agreement is always performed in this phase.
In phase 2 IKE negotiates the IPSec security associations and generates the required key material for IPSec. The sender offers one or more transform sets that are used to specify an allowed combination of transforms with their respective settings.
Benefits provided by IKE include:
Eliminates the need to manually specify all the IPSec security parameters in the crypto maps at both peers.
Allows you to specify a lifetime for the IPSec security association. Allows encryption keys to change during IPSec sessions.
Allows IPSec to provide anti-replay services.
Permits Certification Authority (CA) support for a manageable, scalable IPSec implementation.
Allows dynamic authentication of peers. References:
RFC 2409: The Internet Key Exchange (IKE);
DORASWAMY, Naganand & HARKINS, Dan, Ipsec: The New Security Standard for the Internet, Intranets, and Virtual Private Networks, 1999, Prentice Hall PTR;
SMITH, Richard E., Internet Cryptography, 1997, Addison-Wesley Pub Co. Reference: http://www.ciscopress.com/articles/article.asp?p=25474
- (Topic 6)
Which of the following NAT firewall translation modes offers no protection from hacking attacks to an internal host using this functionality?
Correct Answer:
D
Static translation (also called port forwarding), assigns a fixed address to a specific internal network resource (usually a server).
Static NAT is required to make internal hosts available for connection from external hosts. It merely replaces port information on a one-to-one basis. This affords no protection to
statistically translated hosts: hacking attacks will be just as efficiently translated as any
other valid connection attempt.
NOTE FROM CLEMENT:
Hiding Nat or Overloaded Nat is when you have a group of users behind a unique public IP address. This will provide you with some security through obscurity where an attacker scanning your network would see the unique IP address on the outside of the gateway but could not tell if there is one user, ten users, or hundreds of users behind that IP.
NAT was NEVER built as a security mechanism.
In the case of Static NAT used for some of your servers for example, your web server private IP is map to a valid external public IP on a one on one basis, your SMTP server private IP is mapped to a static public IP, and so on.
If an attacker scan the IP address range on the external side of the gateway he would discover every single one of your servers or any other hosts using static natting. Ports that are open, services that are listening, and all of this info could be gathered just as if the server was in fact using a public IP. It does not provide this security through obscurity mentioned above.
All of the other answer are incorrect. Reference used for this question:
STREBE, Matthew and PERKINS, Charles, Firewalls 24seven, Sybex 2000, Chapter 7:
Network Address Translation.
