Network Security Puzzles on “Secure Shell(SSH)”.
1. In the Key generation procedure, the Integrity Key from the client to server is represented as:
a) HASH(K||H||”E”||session_id)
b) HASH(K||H||”C”||session_id)
c) HASH(K||H||”B”||session_id)
d) HASH(K||H||”D”||session_id)
Answer: a
Clarification: The Initialization Vector from the client to server is given by HASH(K||H||”E”||session_id).
2.In the Key generation procedure, the Integrity Key from the server to client is represented as:
a) HASH(K||H||”A”||session_id)
b) HASH(K||H||”B”||session_id)
c) HASH(K||H||”E”||session_id)
d) HASH(K||H||”F”||session_id)
Answer: d
Clarification: The Initialization Vector from the server to client is given by HASH(K||H||”F”||session_id).
3.In the Key generation procedure, the Encryption key from the server to client is represented as:
a) HASH(K||H||”C”||session_id)
b) HASH(K||H||”B”||session_id)
c) HASH(K||H||”F”||session_id)
d) HASH(K||H||”D”||session_id)
Answer: d
Clarification: The Initialization Vector from the server to client is given by HASH(K||H||”D”||session_id).
4. In the User Authentication Protocol, when the client requests for authentication, then the first byte ( in this format) has decimal value –
a) 80
b) 60
c) 50
d) 61
Answer: c
Clarification: The first byte is assigned a value 50. This is the SSH user authentication message/byte.
5. SSH_MSG_USERAUTH_FALIURE is represented by byte-
a) 50
b) 51
c) 52
d) None of the mentioned
Answer: b
Clarification: SSH_MSG_USERAUTH_FALIURE is represented by 51. This happens in cases when the server (1) either rejects the authentication request or (2) accepts the request but requires one or more additional authentication methods.
6.SSH_MSG_USERAUTH_SUCCESS is represented by the byte –
a) 50
b) 51
c) 60
d) None of the mentioned
Answer: d
Clarification: SSH_MSG_USERAUTH_SUCCESS is represented by 52.
7. Which of the following are valid authentication methods?
a) Public Key Based
b) Password Based
c) Host Based
d) All of the mentioned
Answer: d
Clarification: The server may require one or more of the three authentication methods mentioned above.
8.The SSH Connection Protocol runs on top of the SSH Transport Layer Protocol and assumes that a secure authentication connection is in use.
a) True
b) False
Answer: a
Clarification: The statement is true.The SSH Connection Protocol does run on top of the SSH Transport Layer Protocol.
9. The secure authentication connection is referred to as-
a) chisel
b) tunnel
c) zeroing
d) handshaking
Answer: b
Clarification: The secure connection is referred to as tunnel.
10. The Secure Shell Connection Protocol Message exchange has the fist phase as “Opening a Channel” and it sends a message with parameters-
SSH_MSG_CHANNEL_OPEN
channel type
sender channel
innitial window size
maximum packet size
What is the data type sender channel/innitial window size/ channel type?
a) uint16
b) uint32
c) int16
d) int32
Answer: b
Clarification: The data type is unsigned integer of size 32 bits.
11. In the “Opening a channel” phase what is the function of the “innitial window size” parameter?
a) It specifies the number of bytes in the IV
b) It specifies the maximum size of an individual packet
c) It specifies how many bytes of channel data can be sent
d) None of the mentioned
Answer: c
Clarification: The ‘innitial window size’ specifies how many bytes of channel data can be sent.
12. In the “Opening a channel” phase what is the function of the “maximum packet size” parameter?
a) It specifies the number of bytes in the IV
b) It specifies the maximum size of an individual packet
c) It specifies how many bytes of channel data can be sent
d) None of the mentioned
Answer: b
Clarification: The “maximum packet size” specifies the maximum size of an individual packet.
13. Which is not a channel recognized by the SSH connection protocol?
a) session
b) backward-tcpip
c) direct-tcpip
d) x11
Answer: b
Clarification: Backward-tcpip is not a channel.
14. Which channel ensures local port forwarding?
a) session
b) x11
c) forward-tcpip
d) direct-tcpip
Answer: d
Clarification: Direct-tcpip has the function of local port forwarding.
15.On which port will the server generally listen to for SMTP?
a) port 35
b) port 63
c) port 25
d) port 65
Answer: c
Clarification: The server would have to listen on port 25 for the simple mail transfer protocol.