• What Is Computer Virus
• How does it spread
• Types Of Viruses
• Other Programs similar to Viruses
• Application Security
• Why Application Security Is Important
• Why Often Application Security Is Ignored
• Basic Security Concepts
• Securing the Application
What is a computer virus?
• Computer viruses are a type of software program that is like a
biological virus, replicate and spread without the users
• Some virus may display only a message on the screen, others
may slow down the Pc
• They can also erase files or even format your floppy or hard
disk and crash the system
• Letters looks like they are falling to the bottom of the screen.
• The computer system becomes slow.
• The size of available free memory reduces.
• The hard disk runs out of space.
• The computer does not boot.
How does it spread
• Computer viruses spread by attaching themselves to other
computer program files
• When you exchange a file from pen drive with virus into our Pc,
the virus spreads from one file to the another
• Viruses also spreads when a Computer Engineer comes to repair
your system and puts his/her diagnostics disks in your PC
A virus that takes up permanent residence in the RAM
memory. It can take over or interupt any operation executed
by the computer system. It can corrupt files and programs;
such as copy, open, close, rename and more.
Examples: Randex, CMJ, Meve, and MrKlunky.
Direct Action Virus
A batch file that resides in the root directory of the hard disk.
When executed it will infect files in the directory and also
directed to the batch file AUTOEXEC.BAT file PATH.
A virus that deletes of overwrites part or all of the information
in a file, making them partially or totally worthless. To get
rid of the virus, the file has to be deleted.
Examples of this virus include: Way, Trj.Reboot, Trivial.88.D.
• A virus that affects the boot sector of the hard drive or a
floppy drive. The boot sector gives the computer information
on how to boot, if it is not functioning the computer won't
boot. To avoid a boot virus, don't boot your computer with an
unknown floppy disk in your floppy drive and make sure it is
Examples of boot viruses include: Polyboot.B, AntiEXE.
A virus written in a macro language that infects the files that
were created with it. When the file is opened the macro virus
runs automatically. This may arrive on your computer by
Examples of macro viruses: Relax, Melissa.A, Bablas,
Directory viruses will replace an existing executable and
move the real file somewhere else, so when you run it you are
unknowingly running the virus program instead of the
original. It then becomes impossible to find the original file.
Viruses that encode or encrypt themselves so that each new
version is different. This enables them to replicate and very
hard for virus scanners to track down.
The majority of viruses are file infectors. This virus is
activated by running an executable file like .exe or .com
extension files. Once run, the virus does its damage
according to the program in the executable file.
Once the system is infected they accompany the files that
already exist. They can lay in wait or take action
Some examples include: Stator, Asimov.1539, and
This virus will only infect a computer running a file
allocation table (FAT) file system. This virus will prevent
access to parts of the hard drive preventing files to be
accessed Newer windows computers use NTFS and don't
need to worry about this virus.
Computers Must Exist within a
Use concept of least-privilege
Using Anti Virus Programs
An application is a program or group of programs designed for
Security is the degree of resistance to, or protection from, harm.
It applies to any vulnerable and valuable asset, such as a person,
dwelling, community, nation, or organization.
Application security is the use of software, hardware, and
procedural methods to protect applications from external and
Why Is Application Security
• New threats emerge every day
• Some hackers are not satisfied with penetrating your
network, they seek information that resides in your
• Applications are often with poor designs, software bugs,
and poor programming practices
• Applications may be a fast and have an easy entry point into
a secure network
• Applications contain and process your most critical
(important and sensitive) information
• Programming logic may be exposed to the possibility of being
attacked just as troublesome as difficulties inherent with
Why Is Application Security
Usually there are time and budget constraints in application
development that cause proper testing and secure programming
training to fall to the way aside
Security is typically not prioritized by programming teams, they
are paid to deliver functionality first and foremost
E-commerce initiatives are often rushed into production
Organizations often expect the software manufacturer “build in”
security is 80% process driven, 20% software driven
Four Basic Security Concepts
Poor application security measures can lead to breaches in data:
• Data Integrity means having a secure and reliable data in the
• Protection of information from tampering, forgery, or accidental
• January 2004, there were 13,654 known attacks on Linux
Ensures that applications and data is accessible to only the users
intended and authorized to have access.
Examples : While Login in Providing Id’s and Passwords
Ensures that authorized users have access to the application and
the data when required.
Example: Microsoft Developer Store
Checking PNR Status Indian Railway Systems
Accountability Within the
Ensure accuracy of data and guide against unauthorized
Who did what with your data?
Examples : Having Notification To Our Mobiles From Social
Securing the Application
Authentication & Identification
Authorization & Access Control
Logging & Auditing Procedures
Managing User Sessions
Examples: Ceaser Cipher Text Modification, RSAAlgorithms etc
Every Application must be developed in Ethical hacking
Prevent the loss, modification, or misuse of application systems
“data” or application architecture. Here we are focusing on
Making an e-commerce application secure is much harder than
just adding a password protected login screen!