Systems Security Certified Practitioner – SSCP – Question0882

Secure Shell (SSH-2) provides all the following services except:

A.
secure remote login
B. command execution
C. port forwarding
D. user authentication

Correct Answer: D

Explanation:

This is one of the tricky negative question. You have to pay close attention to the word EXCEPT within the question.
The SSH transport layer is a secure, low level transport protocol. It provides strong encryption, cryptographic host authentication, and integrity protection.
Authentication in this protocol level is host-based; this protocol does not perform user authentication. A higher level protocol for user authentication can be designed on top of this protocol.
The protocol has been designed to be simple and flexible to allow parameter negotiation, and to minimize the number of round-trips. The key exchange method, public key algorithm, symmetric encryption algorithm, message authentication algorithm, and hash algorithm are all negotiated. It is expected that in most environments, only 2 round-trips will be needed for full key exchange, server authentication, service request, and acceptance notification of service request. The worst case is 3 round-trips.
The following are incorrect answers:
“Remote log-on” is incorrect. SSH does provide remote log-on. “Command execution” is incorrect. SSH does provide command execution.
“Port forwarding” is incorrect. SSH does provide port forwarding. SSH also has a wonderful feature called SSH Port Forwarding, sometimes called SSH Tunneling, which allows you to establish a secure SSH session and then tunnel arbitrary TCP connections through it. Tunnels can be created at any time, with almost no effort and no programming, which makes them very appealing. See the article below in the reference to take a look at SSH Port Forwarding in detail, as it is a very useful but often misunderstood technology. SSH Port Forwarding can be used for secure communications in a myriad of different ways.
You can see a nice tutorial on the PUTTY web site on how to use PUTTY to do port forwarding at: http://www.cs.uu.nl/technical/services/ssh/putty/puttyfw.html
Reference(s) used for this question: RFC 4253 at https://www.ietf.org/rfc/rfc4253.txt and SSH Port Forwarding by Symantec