The document outlines essential security practices for application development, emphasizing the need for protection of sensitive information from attacks such as data sniffing and unauthorized access. It provides examples, including the internet payment company 'paybuddy,' which failed to secure credit card information leading to potential fraud. Additionally, it stresses proper data handling protocols, such as only storing necessary information and utilizing encryption, to mitigate privacy issues and protect user data.

1. Data Protection & Privacy
Application Security Fundamentals
by Secure Code Warrior Limited is licensed under CC BY-ND 4.0

2. The application should implement
security controls to ensure the
protection and integrity of its
sensitive information.
What could happen?
An attacker could retrieve sensitive
and private information through
stolen log files, caching, man-in-the-
middle attacks or other means.
How to implement it?
Only store private information
that is absolutely required. Make
sure any stored or transmitted
information is properly secured
using encryption.
What’s the concept
about?

3. An internet payment company
called “Paybuddy” is taking
precautions to protect its
customers from credit card theft.
Communications to and from
the site are protected using
TLS, preventing attackers from
sniffing the traffic.
Credit card numbers are
stored encrypted in the
database using a strong
algorithm.
Credit card numbers are never
displayed in full, so attackers
cannot view the numbers
through shoulder surfing.
Caching is turned off as well.
Data Protection & Privacy
Understanding the concept
Properly protected
data
Web application
User: John
Doe
User Credit Card
John 69d4a73c196f60c3e453a9832fb4
admin 086569d4a73c196f60c3e453a983
Bart a73c196f60c3e453a9832fb4fz90o
bcrypt(creditcard)
CC:
XXXXXXX420

4. This time, “Paybuddy”
forgot to take
precautions to properly
protect their customers
and their data.
An attacker sniffs traffic between the
client and the server. He is able to steal
sensitive information, such as the
user’s credit card number.
An attacker that is able to
retrieve weakly hashed
credit card numbers won’t
have difficulties to decrypt
them using rainbow tables.
An attacker that is shoulder
surfing can see a full credit card
number in the application, which
can be abused to commit fraud.
Data Protection & Privacy
What could happen with the concept?
Unprotected data
Web application
User: John
Doe
User Credit Card
John a73c196f60c3e453a9832fb4
admin 69d4a73c196f60c3e453a983
Bart a7360c3e453a9832fb4fz90o
md5(creditcard)
User: John Doe
CC:
475629420
CC:
475629420

5. A software company is very
careful in protecting the
source code of their new
mobile application.
The source code repository is stored
on encrypted hardware in a secured
server room.
To protect the source
code in production,
heavy obfuscation
techniques are applied
to the application.
The source code repository can only
be accessed from their internal
network. Access to the repository is
limited to developers with the right
clearance.
Data Protection & Privacy
Understanding the concept Source code
protection
0101011
1010010
1001010
1011011
1001010
Developer X
Developer Y
Developer Z

6. The company’s intellectual
property is in danger due to
a lack of source code
protection.
The repository is stored on a
physically accessible server. Local
attackers can copy the code,
which is stored in clear text.
Without obfuscation, users can
decompile the application and
retrieve the source. It can be
modified and repackaged to be
sold by a third party.
The repository is publicly
accessible and therefore easier
to target by attackers.
Data Protection & Privacy
What could happen with the concept? Source code
unprotected
0101011
1010010
1001010
1011011
1001010
Developer X
Developer Y

7. Data Protection & Privacy
Understanding the concept User’s privacy
respected
User: John Doe
DoB: 29/02/1973
Sex: M
Location: Sydney
Religion: Pastafari
John’s
info DB Admin
A certain web application
allows users to create a
profile. The application
stores date of birth, sex,
location, and religion.
The user’s private information
is stored in a database with
restricted access.
Only the database administrator has
access to the database and the
information. Additionally, he had to
sign a non-disclosure agreement.

8. A certain web application
allows users to create a
profile. The application
stores date of birth, sex,
location, and religion.
The user’s private information
is stored in a database with
restricted access.
All developers working on the
application can view the user’s
private information in the
development database. This
clearly causes privacy issues.
Before a new release, the
database contents is copied to
a development environment for
testing purposes.
Data Protection & Privacy
What could happen with the concept?
Privacy issues
User: John Doe
DoB: 29/02/1973
Sex: M
Location: Sydney
Religion: Pastafari
John’s
info
John’s
info
Developer 1
Developer 2
Development

9. Data Protection & Privacy
Typical controls
Only store private information if absolutely needed.
Don’t hard-code secret information in source code.
Don’t store DB credentials or encryptions keys in plain text.
Securely store all sensitive user information.
Send traffic over a secure communication channel.
Inform users using a privacy policy.