398 Appendix ■ Answers
4 7. B. Chris is in an Agile sprint phase and is likely developing code based on user stories.
Planning includes stakeholder stories, as well as design and test case preparation.
Deployment includes the actual deployment of the application, as well as additional
verification and testing.- D. This question is asking you to identify the blocking rule that should NOT be set on the
firewall. Packets with public IP addresses will routinely be allowed to enter the network,
so you should not create a rule to block them, making this the correct answer. Packets
with internal source addresses should never originate from outside the network, so they
should be blocked from entering the network. Packets with external source addresses
should never be found on the internal network, so they should be blocked from leaving
the network. Finally, private IP addresses should never be used on the Internet, so packets
containing private IP addresses should be blocked from leaving the network. - B. This is an example of a specific type of buffer overflow known as an off-by-one error.
The first line of the code defines an array of 10 elements, which would be numbered 0
through 9. The second line of code tries to place a value in the 11th element of the array
(remember, array counting begins at 0!), which would cause an overflow. - C. Lost updates occur when one transaction writes a value to the database that overwrites
a value needed by transactions that have earlier precedence, causing those transactions
to read an incorrect value. Dirty reads occur when one transaction reads a value from
a database that was written by another transaction that did not commit. Incorrect
summaries occur when one transaction is using an aggregate function to summarize data
stored in a database while a second transaction is making modifications to the database,
causing the summary to include incorrect information. SQL injection is a web application
security flaw, not a database concurrency problem. - A. Transport Layer Security (TLS) provides the most effective defense against session
hijacking because it encrypts all traffic between the client and server, preventing the
attacker from stealing session credentials. Secure Sockets Layer (SSL) also encrypts traffic,
but it is vulnerable to attacks against its encryption technology. Complex and expiring
cookies are a good idea, but they are not sufficient protection against session hijacking. - C. When a system uses shadowed passwords, the hashed password value is stored in
/etc/shadow instead of /etc/passwd. The /etc/passwd file would not contain the password
in plaintext or hashed form. Instead, it would contain an x to indicate that the password
hash is in the shadow file. The * character is normally used to disable interactive logins to
an account. - B. Time of check to time of use (TOCTOU) attacks target situations where there is a
race condition, meaning that a dependence on the timing of actions allows impermissible
actions to take place. - C. The single quotation mark in the input field is a telltale sign that this is a SQL injection
attack. The quotation mark is used to escape outside the SQL code’s input field, and
the text following is used to directly manipulate the SQL command sent from the web
application to the database.