(2) What types of attacks are addressed by message authentication
Answers
Masquerade Attack
Masquerade attacks may happen in a number of ways. In case of an insider attack, a masquerade attacker gains access to the account of a legitimate user either by stealing the victim's account ID and password, or by using a keylogger. Another common method is by exploiting a legitimate user's laziness and trust. For example, if a legitimate user leaves the terminal or session open and logged in, a co-worker may act as a masquerade attacker.
Vulnerable authentication is one of the other factors that can trigger a masquerade attack, as it helps the attacker to gain access much more easily. Once the attackers gain access, they can get into all of the organization's critical data and can delete or modify it, steal sensitive data, or alter routing information and network configuration.
For example, although a unique IP address is assigned to each individual computer, a hacker can convince another system that it is the authorized user through spoofing, essentially convincing the target computer that the hacker's computer has the same IP.