Highly sensitive data is stored in a database and is accessed by an application on a DMZ server. The disk drives on all servers are fully encrypted. Communication
between the application server and end-users is also encrypted. Network ACLs prevent any connections to the database server except from the application server.
Which of the following can still result in exposure of the sensitive data in the database server?

A.
SQL Injection

B.
Theft of the physical database server

C.
Cookies

D.
Cross-site scripting

Explanation:
The question discusses a very secure environment with disk and transport level encryption and access control lists restricting access. SQL data in a database is
accessed by SQL queries from an application on the application server. The data can still be compromised by a SQL injection attack.
SQL injection is a code injection technique, used to attack data-driven applications, in which malicious SQL statements are inserted into an entry field for execution
(e.g. to dump the database contents to the attacker). SQL injection must exploit a security vulnerability in an application’s software, for example, when user input is
either incorrectly filtered for string literal escape characters embedded in SQL statements or user input is not strongly typed and unexpectedly executed. SQL
injection is mostly known as an attack vector for websites but can be used to attack any type of SQL database.
Incorrect Answers:
B: Theft of the physical database server would not expose the sensitive data in the database server because the disks are encrypted. You would need the
certificate used to encrypt the data in order to decrypt the data on the disks. Therefore, this answer is incorrect.
C: Cookies are text files stored on a user’s computer to store website information. This is to provide the user with a consistent website browsing experience.
Cookies do not pose a risk to the sensitive data on the database server. Therefore, this answer is incorrect.
D: Cross-site scripting (XSS) is a type of computer security vulnerability typically found in Web applications. XSS enables attackers to inject client-side script into
Web pages viewed by other users.
Cross-site scripting uses known vulnerabilities in web-based applications, their servers, or plug- in systems on which they rely. Exploiting one of these, attackers
fold malicious content into the content being delivered from the compromised site. When the resulting combined content arrives at the client-side web browser, it
has all been delivered from the trusted source, and thus operates under the permissions granted to that system. By finding ways of injecting malicious scripts into
web pages, an attacker can gain elevated access-privileges to sensitive page content, session cookies, and a variety of other information maintained by the
browser on behalf of the user. The sensitive data is stored in databases on the database server. It is therefore not vulnerable to an XSS attack. Therefore, this
answer is incorrect.

http://en.wikipedia.org/wiki/SQL_injection

http://en.wikipedia.org/wiki/Cross-site_scripting