Explanation/Reference:
Explanation:
The Bell-LaPadula model deals only with confidentiality, while the Biba and Clark-Wilson models deal only with integrity.
The Clark-Wilson model addresses all three integrity goals: prevent unauthorized users from making modifications, prevent authorized users from making improper modifications, and maintain internal and external consistency.
Incorrect Answers:
A: The Clark-Wilson security model does not focus on confidentiality; it focuses on integrity.
C: The Clark-Wilson security model does not focus on accountability; it focuses on integrity.
D: The Clark-Wilson security model does not focus on availability; it focuses on integrity.
References:
Harris, Shon, All In One CISSP Exam Guide, 6th Edition, McGraw-Hill, New York, 2013, pp. 414, 416

Section: Security and Risk Management
Explanation/Reference: https://www.google.com/url?
sa=t&rct=j&q=&esrc=s&source=web&cd=1&cad=rja&uact=8&ved=0ahUKEwjbktbTp- LaAhVIr48KHZuhB0UQFggmMAA&url=http%3A%2F%2Fwww.oregon.gov%2Fdas%2FProcurement%
2FGuiddoc%2FBusImpAnalysQs.doc&usg=AOvVaw1wBxcnLP8ceI_yhv2rsI9h

The original TACACS, developed in the early ARPANet days, had very limited functionality and used the UDP transport. In the early 1990s, the protocol was extended to include additional functionality and the transport changed to TCP. TACACS is defined in RFC 1492, and uses (either TCP or UDP) port 49 by default. TACACS allows a client to accept a username and password and send a query to a TACACS authentication server, sometimes called a TACACS daemon or simply TACACSD. TACACSD uses TCP and usually runs on port 49 It would determine whether to accept or deny the authentication request and send a response back. TACACS+ TACACS+ and RADIUS have generally replaced TACACS and XTACACS in more recently built or updated networks. TACACS+ is an entirely new protocol and is not compatible with TACACS or XTACACS. TACACS+ uses the Transmission Control Protocol (TCP) and RADIUS uses the User Datagram Protocol (UDP). Since TCP is connection oriented protocol, TACACS+ does not have to implement transmission control. RADIUS, however, does have to detect and correct transmission errors like packet loss, timeout etc. since it rides on UDP which is connectionless. RADIUS encrypts only the users' password as it travels from the RADIUS client to RADIUS server. All other information such as the username, authorization, accounting are transmitted in clear text. Therefore it is vulnerable to different types of attacks. TACACS+ encrypts all the information mentioned above and therefore does not have the vulnerabilities present in the RADIUS protocol. RADIUS and TACACS + are client/ server protocols, which means the server portion cannot send unsolicited commands to the client portion. The server portion can only speak when spoken to. Diameter is a peer-based protocol that allows either end to initiate communication. This
functionality allows the Diameter server to send a message to the access server to request the
user to provide another authentication credential if she is attempting to access a secure resource.
Reference(s) used for this question:
http://en.wikipedia.org/wiki/TACACS
and
Harris, Shon (2012-10-18). CISSP All-in-One Exam Guide, 6th Edition (p. 239). McGraw-Hill.
Kindle Edition.

A TCP sequence number attack exploits the communication session which was established between the target and the trusted host that initiated the session. It involves hijacking the session between the host and the target by predicting the target's choice of an initial TCP sequence number. An IP spoofing attack is used to convince a system that it is communication with a known entity that gives an intruder access. It involves modifying the source address of a packet for a trusted source's address. A SYN attack is when an attacker floods a system with connection requests but does not respond when the target system replies to those requests. A smurf attack occurs when an attacker sends a spoofed (IP spoofing) PING (ICMP ECHO) packet to the broadcast address of a large network (the bounce site). The modified packet containing the address of the target system, all devices on its local network respond with a ICMP REPLY to the target system, which is then saturated with those replies.
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 77).

Reference: http://ssae16.businesscatalyst.com/SSAE16_reports.html