Page 9 - Security+ (635 notes by Nikkhah)

access to a system.
104- Trojan horses and rootkits are known to use the back door process to exploit a system.

105- A symmetric back door application allows anyone to use it.

106- An asymmetric back door application is used only by its creator.

Types of malicious code
107- Malicious code, or malware, is an application used to gain access to a system without the

user’s knowledge or permission.
108- Malware includes viruses, Trojan horses, worms, and applications such as adware,

spyware, botnets, or loggers.

Virus

109- A virus is a self-replicating application.
110- It inserts into an executable and spreads when the file is run.

111- A bootstrap virus infects the boot sector of the hard disk.
112- A parasitic virus resides in an executable file.

Worm

113- A worm resides in the active memory of the computer and is usually not noticeable.

114- It keeps scanning the network for vulnerabilities.
115- It spreads itself on to other computers in the network.

Trojan horse
116- A Trojan horse is malicious code embedded inside a legitimate application.

117- It appears as a very useful application to the user.
118- It is used to collect personal information about the user.

119- Most spyware, adware, and pop-up windows fall into this category.

Logic bombs and Time bombs

120- A logic bomb is malicious code that waits for some condition to be met before it executes.
121- It can also execute when some event happens.

122- A time bomb is another type of malicious code that waits for a particular time to execute.

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