B.

Brute force

Brute force attacks are performed with tools that cycle through many possible character,
number, and symbol combinations to guess a password. Since the token allows offline
checking of PIN, the cracker can keep trying PINS until it is cracked.

C.

Air Snort implements the FMS attack and only encrypted packets are counted

Since the summer of 2001, WEP cracking has been a trivial but time consuming process. A few tools, AirSnort perhaps the most famous, that implement the Fluhrer-Mantin-Shamir (FMS) attack were released to the security community - who until then were aware of the problems with WEP but did not have practical penetration testing tools. Although simple to use, these tools require a very large number of packets to be gathered before being able to crack a WEP key. The AirSnort web site estimates the total
number of packets at five to ten million, but the number actually required may be higher than you think.

C.

nobody, dns

Passwd is the command used to modify a user password and it has been used together with the usernames nobody and dns.

A.

The switches will drop into hub mode if the ARP cache is successfully flooded.

D.

SYN, SYN-ACK, ACK

A TCP connection always starts with a request for synchronization, a SYN,
the reply to that would be another SYN together with a ACK to acknowledge that the last
package was delivered successfully and the last part of the three way handshake should
be only an ACK to acknowledge that the SYN reply was recived.

B.

Create rules in IDS to alert on strange Unicode requests.

This is a typical Unicode attack. By configuring your IDS to trigger on strange
Unicode requests you can protect your web-server from this type of attacks.

C.

You can conceal the Sales.xls database in another file like photo.jpg or other files and
send it out in an innocent looking email or file transfer using Steganography techniques

D.

Bad quality assurance on software produced.

Technically, a buffer overflow is a problem with the program's internal
implementation.