Download - Computer security basics
Introduction to
Computer security
By, P.srinu 24
COMPUTER SECURITY
Why?:to protect the computing system and protect the data that they store and access Security attacks :- actions that
comprises the computer security Security mechanisms:-tools such
as algorithms, protocols designed to detect ,prevent or recover from a security attack
Security services :-specific kind of protection to the system resources
SECURITY THREAT
• Threat potential violation of security and also causes harm.• Vulnerability a weakness
that is left unprotected.
SECURITY ATTACKPassive attack:getting information from the
system ,but it does not affect the system. analyzing the traffic to find the nature of
communication difficult to detect as they do not involve
alteration of the data Hence better to Prevent rather than
Detection
Active Attack: tries to alter the system resources or affect its operations.
Masquerade replay(capture events and replay) Modifications of messages Denial of services
“Difficult to prevent but can be detected and recovered “
TARGET
users• identity• privacy of user
» eg.pin(personal identification number) of atm,credit card, login id’s, pass codes
How ?? tracking of users habits and actionsWhat??Cookies(cannot install malware) and spam mails are
used for attacking
Attacks on computer hardware• Natural calamities such as Floods,
Earthquakes, power fluctuations.• Destructive actions of burglars or people
Attacks on softwareAim? to harm the data stored and programs in
computer how??Executables files:- programs written to do harm
rather than goodWhat??malicious software :-a software code included
into the system which is harmful in natureHacking:-intruding into another computer or
network to perform an illegal act
MALICIOUS SOFTWARE
A software program which is Destructive in nature. Characteristics can attach itself to other healthy programs. replicates itself and thus can spread across a
network Infects an executable file or program Cannot infect write protect disks , hardware,
compressed files How dies it harm?
• Corrupt or delete data, change functionality of software , erase everything on the hard disk, degrade the system performance.
What?? E mail attachment, downloads on internet.
Eg. I love you, melissa,Brain, anna kournikova……….
VIRUS
Java scripts ,java applets and Activex controls
• Java applets :- it can be part of a web page and executed by the Java Virtual Machine executed by browsers for many platforms, including Microsoft Windows ,Unix, Linux etc.
• ActiveX controls:- similar to java applets but do not have security checks
• Java scripts:-a scripting language commonly implemented as part of a web browser in order to create enhanced user interfaces and dynamic websites
WORMS
• Self replicating software that uses network and security holes
• it scans the network of a system and copies itself and then starts replicating from there.
• Worm and virus are different
• Consumes the resources like bandwidth of computer and makes it slow.
E.g. nimda(multiple infectious virus), code red (Chinese),
TROJAN HORSE• It is a destructive program that
masquerade as useful program.
• The reason behind the name is the Greek soldiers who reached the city of troy by hiding in the wooden horse. Similarly games, software etc. can corrupt Data, Programs or damage files
???queries???