Following are the common security problems involved in communications and email:
Eavesdropping: It is the act of secretly listening to private information through telephone lines, e-
mail, instant messaging, and any other method of communication considered private.
Identity theft: It is the act of obtaining someone's username and password to access his/her email
servers for reading email and sending false email messages. These credentials can be obtained
by eavesdropping on SMTP, POP, IMAP, or Webmail connections.
Message modification: The person who has system administrator permission on any of the SMTP
servers can visit anyone's message and can delete or change the message before it continues on
to its destination. The recipient has no way of telling that the email message has been altered.
False message: It the act of constructing messages that appear to be sent by someone else.
Message replay: In a message replay, messages are modified, saved, and re-sent later.
Message repudiation: In message repudiation, normal email messages can be forged. There is no
way for the receiver to prove that someone had sent him/her a particular message. This means
that even if someone has sent a message, he/she can successfully deny it.
Answer option B is incorrect. A message digest is a number that is created algorithmically from a
file and represents that file uniquely.

AirSnort is a Linux-based WLAN WEP cracking tool that recovers encryption keys. AirSnort operates by passively monitoring transmissions. It uses Ciphertext Only Attack and captures approximately 5 to 10 million packets to decrypt the WEP keys. Answer option B is incorrect. Kismet is a Linux-based 802.11 wireless network sniffer and intrusion detection system. It can work with any wireless card that supports raw monitoring (rfmon) mode. Kismet can sniff 802.11b, 802.11a, 802.11g, and 802.11n traffic. Kismet can be used for the following tasks: To identify networks by passively collecting packets To detect standard named networks To detect masked networks To collect the presence of non-beaconing networks via data traffic Answer option D is incorrect. Cain is a multipurpose tool that can be used to perform many tasks such as Windows password cracking, Windows enumeration, and VoIP session sniffing. This password cracking program can perform the following types of password cracking attacks: Dictionary attack Brute force attack Rainbow attack Hybrid attack Answer option A is incorrect. PsPasswd is a tool that helps Network Administrators change an account password on the local or remote system. The command syntax of PsPasswd is as follows: pspasswd [\\computer[,computer[,..] | @file [-u user [-p psswd]] Username [NewPassword]