CompTIA CompTIA Security+ JK0-022 Questions & Answers

• Question 221:

  Which of the following application attacks is used against a corporate directory service where there are unknown servers on the network?

  A. Rogue access point

  B. Zero day attack

  C. Packet sniffing

  D. LDAP injection

  Correct Answer: D

  A directory service is accessed by using LDAP (Lightweight Directory Access Protocol). LDAP injection is an attack against a directory service. Just as SQL injection attacks take statements that are input by users and exploit weaknesses within, an LDAP injection attack exploits weaknesses in LDAP (Lightweight Directory Access Protocol) implementations. This can occur when the user's input is not properly filtered, and the result can be executed commands, modified content, or results returned to unauthorized queries. The best way to prevent LDAP injection attacks is to filter the user input and to use a validation scheme to make certain that queries do not contain exploits. One of the most common uses of LDAP is associated with user information. Numerous applications exist--such as employee directories--where users find other users by typing in a portion of their name. These queries are looking at the cn value or other fields (those defined for department, home directory, and so on). Someone attempting LDAP injection could feed unexpected values to the query to see what results are returned. All too often, finding employee information equates to finding usernames and values about those users that could be portions of their passwords.

  Incorrect Answers:

  A: A rogue access point is a wireless access point that has either been installed on a secure company network without explicit authorization from a local network administrator, or has been created to allow a hacker to conduct a man-in-themiddle attack. Rogue access points of the first kind can pose a security threat to large organizations with many employees, because anyone with access to the premises can install (maliciously or non-maliciously) an inexpensive wireless router that can potentially allow access to a secure network to unauthorized parties. Rogue access points of the second kind target networks that do not employ mutual authentication (client-server server-client) and may be used in conjunction with a rogue RADIUS server, depending on security configuration of the target network. Rogue access points are not used for application attacks used against a corporate directory service. Therefore this answer is incorrect.

  B: A zero day vulnerability refers to a hole in software that is unknown to the vendor. This security hole is then exploited by hackers before the vendor becomes aware and hurries to fix it --this exploit is called a zero day attack. Uses of zero day attacks can include infiltrating malware, spyware or allowing unwanted access to user information. The term "zero day" refers to the unknown nature of the hole to those outside of the hackers, specifically, the developers. Once the vulnerability becomes known, a race begins for the developer, who must protect users. A zero day attack is generally not used for application attacks against a corporate directory service. Therefore this answer is incorrect.

  C: Packet sniffing is the process of intercepting data as it is transmitted over a network. A sniffer (packet sniffer) is a tool that intercepts data flowing in a network. If computers are connected to a local area network that is not filtered or switched, the traffic can be broadcast to all computers contained in the same segment. This doesn't generally occur, since computers are generally told to ignore all the comings and goings of traffic from other computers. However, in the case of a sniffer, all traffic is shared when the sniffer software commands the Network Interface Card (NIC) to stop ignoring the traffic. Packet sniffing is not used for application attacks against a corporate directory service. Therefore this answer is incorrect.

  References: C Dulaney, Emmett and Chuck Eastton, CompTIA Security+ Study Guide, Sixth Edition, Sybex, Indianapolis, 2014, pp 336-337 http://en.wikipedia.org/wiki/Rogue_access_point http://www.pctools.com/security-news/zero-day-vulnerability/ http://www.techopedia.com/definition/4113/sniffer

• Question 222:

  An attacker attempted to compromise a web form by inserting the following input into the username field: admin)(|(password=*)) Which of the following types of attacks was attempted?

  A. SQL injection

  B. Cross-site scripting

  C. Command injection

  D. LDAP injection

  Correct Answer: D

  LDAP Injection is an attack used to exploit web based applications that construct LDAP statements based on user input. When an application fails to properly sanitize user input, it's possible to modify LDAP statements using a local proxy.

  This could result in the execution of arbitrary commands such as granting permissions to unauthorized queries, and content modification inside the LDAP tree. The same advanced exploitation techniques available in SQL Injection can be

  similarly applied in LDAP Injection.

  In a page with a user search form, the following code is responsible to catch input value and generate a LDAP query that will be used in LDAP database. Insert the username The LDAP

  query is narrowed down for performance and the underlying code for this function might be the following:

  String ldapSearchQuery = "(cn=" + $userName + ")";

  System.out.println(ldapSearchQuery);

  If the variable $userName is not validated, it could be possible accomplish LDAP injection, as follows:

  If a user puts "*" on box search, the system may return all the usernames on the LDAP base If a user puts "jonys) (| (password = * ) )", it will generate the code bellow revealing jonys' password ( cn = jonys ) ( | (password = * ) )

  Incorrect Answers:

  A: 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. The code in this question is not SQL code.

  Therefore this answer is incorrect.

  B: 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 code in this question is not an example of

  cross-site scripting code. Therefore, this answer is incorrect.

  C: Command injection is an attack method in which a hacker alters dynamically generated content on a Web page by entering HTML code into an input mechanism, such as a form field that lacks effective validation constraints. The code in

  this question is not HTML code.

  Therefore this answer is incorrect.

  References: https://www.owasp.org/index.php/LDAP_injection http://en.wikipedia.org/wiki/SQL_injection http://en.wikipedia.org/wiki/Cross-site_scripting http://searchsoftwarequality.techtarget.com/definition/command-injection

• Question 223:

  Which of the following BEST describes a SQL Injection attack?

  A. The attacker attempts to have the receiving server pass information to a back-end database from which it can compromise the stored information.

  B. The attacker attempts to have the receiving server run a payload using programming commonly found on web servers.

  C. The attacker overwhelms a system or application, causing it to crash and bring the server down to cause an outage.

  D. The attacker overwhelms a system or application, causing it to crash, and then redirects the memory address to read from a location holding the payload.

  Correct Answer: A

  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: "using programming commonly found on web servers" describes a cross-site scripting or XML injection attack. It does not describe a SQL injection attack. Therefore, this answer is incorrect.

  C: Examples of an attack that "overwhelms a system or application, causing it to crash and bring the server down" are DDoS attack, Syn floods and other flooding attacks. The description does not describe a SQL injection attack. Therefore, this answer is incorrect.

  D: The description "overwhelms a system or application, causing it to crash, and then redirects the memory address to read from a location holding the payload" is describing a buffer overflow attack, not an SQL injection attack. Therefore, this answer is incorrect.

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

• Question 224:

  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

  Correct Answer: A

  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.

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

• Question 225:

  When an order was submitted via the corporate website, an administrator noted special characters (e.g., ";--" and "or 1=1 --") were input instead of the expected letters and numbers.

  Which of the following is the MOST likely reason for the unusual results?

  A. The user is attempting to highjack the web server session using an open-source browser.

  B. The user has been compromised by a cross-site scripting attack (XSS) and is part of a botnet performing DDoS attacks.

  C. The user is attempting to fuzz the web server by entering foreign language characters which are incompatible with the website.

  D. The user is sending malicious SQL injection strings in order to extract sensitive company or customer data via the website.

  Correct Answer: D

  The code in the question is an example of a SQL Injection attack. The code `1=1' will always provide a value of true. This can be included in statement designed to return all rows in a SQL table.

  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:

  A: Session hijacking, also known as TCP session hijacking, is a method of taking over a Web user session by surreptitiously obtaining the session ID and masquerading as the authorized user. Once the user's session ID has been accessed (through session prediction), the attacker can masquerade as that user and do anything the user is authorized to do on the network. The code in the question is not an example of session hijacking. Therefore, this answer is incorrect.

  B: A distributed denial-of-service (DDoS) attack occurs when multiple systems flood the bandwidth or resources of a targeted system, usually one or more web servers. Such an attack is often the result of multiple compromised systems (for example a botnet) flooding the targeted system with traffic. When a server is overloaded with connections, new connections can no longer be accepted. The major advantages to an attacker of using a distributed denial-of-service attack are that multiple machines can generate more attack traffic than one machine, multiple attack machines are harder to turn off than one attack machine, and that the behavior of each attack machine can be stealthier, making it harder to track and shut down. These attacker advantages cause challenges for defense mechanisms. For example, merely purchasing more incoming bandwidth than the current volume of the attack might not help, because the attacker might be able to simply add more attack machines. This after all will end up completely crashing a website for periods of time. The code in the question is not an example of the data that would be sent in a DDoS attack. Therefore, this answer is incorrect.

  C: Fuzz testing or fuzzing is a software testing technique used to discover coding errors and security loopholes in software, operating systems or networks by inputting massive amounts of random data, called fuzz, to the system in an attempt

  to make it crash. The code in the question does not contain foreign language characters; it is code typically used in a SQL injection attack.

  Therefore, this answer is incorrect.

  References: http://en.wikipedia.org/wiki/SQL_injection http://searchsoftwarequality.techtarget.com/definition/session-hijacking http://en.wikipedia.org/wiki/Denial-of-service_attack

• Question 226:

  The string:

  ` or 1=1--

  Represents which of the following?

  A. Bluejacking

  B. Rogue access point

  C. SQL Injection

  D. Client-side attacks

  Correct Answer: C

  The code in the question is an example of a SQL Injection attack. The code `1=1' will always provide a value of true. This can be included in statement designed to return all rows in a SQL table.

  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:

  A: Bluejacking is the sending of unsolicited messages over Bluetooth to Bluetooth-enabled devices such as mobile phones, PDAs or laptop computers, sending a vCard which typically contains a message in the name field (i.e., for bluedating or bluechat) to another Bluetooth- enabled device via the OBEX protocol. The code in the question is not an example of bluejacking. Therefore, this answer is incorrect.

  B: A rogue access point is a wireless access point that has either been installed on a secure company network without explicit authorization from a local network administrator, or has been created to allow a hacker to conduct a man-in-themiddle attack. Rogue access points of the first kind can pose a security threat to large organizations with many employees, because anyone with access to the premises can install (maliciously or non-maliciously) an inexpensive wireless router that can potentially allow access to a secure network to unauthorized parties. Rogue access points of the second kind target networks that do not employ mutual authentication (client-server server-client) and may be used in conjunction with a rogue RADIUS server, depending on security configuration of the target network. A rogue access point would not create the code shown in the question. Therefore, this answer is incorrect.

  D: Client-side attacks target vulnerabilities in client applications interacting with a malicious data. The difference is the client is the one initiating the bad connection. The code in the question is much more likely to be part of a SQL statement in a SQL Injection attack. Therefore, this answer is incorrect. References: http://en.wikipedia.org/wiki/SQL_injection http://en.wikipedia.org/wiki/Bluejacking http://en.wikipedia.org/wiki/Rogue_access_point

• Question 227:

  Which of the following types of application attacks would be used to specifically gain unauthorized information from databases that did not have any input validation implemented?

  A. SQL injection

  B. Session hijacking and XML injection

  C. Cookies and attachments

  D. Buffer overflow and XSS

  Correct Answer: A

  To access information in databases, you use SQL. To gain unauthorized information from databases, a SQL Injection attack is used.

  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: When a web user takes advantage of a weakness with SQL by entering values that they should not, it is known as a SQL injection attack. Similarly, when the user enters values that query XML (known as XPath) with values that take

  advantage of exploits, it is known as an XML injection attack. XPath works in a similar manner to SQL, except that it does not have the same levels of access control, and taking advantage of weaknesses within can return entire documents.

  The best way to prevent XML injection attacks is to filter the user's input and sanitize it to make certain that it does not cause XPath to return more data than it should. XML Injection is not used to gain unauthorized information from

  databases. This answer is therefore incorrect.

  C: Cookies are used to store information about web browsing sessions. Cookies and attachments are not used to gain unauthorized information from databases.

  This answer is therefore 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.

  A buffer overflow occurs when a program or process tries to store more data in a buffer (temporary data storage area) than it was intended to hold. Since buffers are created to contain a finite amount of data, the extra information - which has

  to go somewhere - can overflow into adjacent buffers, corrupting or overwriting the valid data held in them. Although it may occur accidentally through programming error, buffer overflow is an increasingly common type of security attack on

  data integrity.

  Buffer overflow and XSS are not used to gain unauthorized information from databases. This answer is therefore incorrect.

  References: http://en.wikipedia.org/wiki/SQL_injection Dulaney, Emmett and Chuck Eastton, CompTIA Security+ Study Guide, Sixth Edition, Sybex, Indianapolis, 2014, 337

• Question 228:

  A security administrator looking through IDS logs notices the following entry: (where [email protected] and passwd= `or 1==1')

  Which of the following attacks had the administrator discovered?

  A. SQL injection

  B. XML injection

  C. Cross-site script

  D. Header manipulation

  Correct Answer: A

  The code in the question is an example of a SQL Injection attack. The code `1==1' will always provide a value of true. This can be included in statement designed to return all rows in a SQL table.

  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:

  A: 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 code in this question in not used for an XSS attack. Therefore, this answer is incorrect.

  B: When a web user takes advantage of a weakness with SQL by entering values that they should not, it is known as a SQL injection attack. Similarly, when the user enters values that query XML (known as XPath) with values that take advantage of exploits, it is known as an XML injection attack. XPath works in a similar manner to SQL, except that it does not have the same levels of access control, and taking advantage of weaknesses within can return entire documents. The best way to prevent XML injection attacks is to filter the user's input and sanitize it to make certain that it does not cause XPath to return more data than it should. The code in this question in not XML code. This is therefore not an XML Injection attack.

  D: Header manipulation is an attack on an application that access web pages or web services. It involves introducing unvalidated data in an HTTP response header which can enable cache- poisoning, cross-site scripting, cross-user defacement, page hijacking, cookie manipulation or open redirect. The code in the question is not the code you would expect to see in a header manipulation attack. This answer is therefore incorrect.

  References: http://en.wikipedia.org/wiki/SQL_injection http://en.wikipedia.org/wiki/Cross-site_scripting Dulaney, Emmett and Chuck Eastton, CompTIA Security+ Study Guide, Sixth Edition, Sybex, Indianapolis, 2014, p 337

• Question 229:

  Which of the following BEST describes a protective countermeasure for SQL injection?

  A. Eliminating cross-site scripting vulnerabilities

  B. Installing an IDS to monitor network traffic

  C. Validating user input in web applications

  D. Placing a firewall between the Internet and database servers

  Correct Answer: C

  By validating user input and preventing special characters, we can prevent the injection of client- side scripting code. 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:

  A: Eliminating cross-site scripting vulnerabilities is always a good idea. However, that will not prevent SQL Injection attacks. Therefore this answer is incorrect.

  B: An intrusion detection system (IDS) is a device or software application that monitors network or system activities for malicious activities or policy violations and produces reports to a management station. IDS come in a variety of "flavors"

  and approach the goal of detecting suspicious traffic in different ways. There are network based (NIDS) and host based (HIDS) intrusion detection systems. Some systems may attempt to stop an intrusion attempt but this is neither required

  nor expected of a monitoring system. Intrusion detection and prevention systems (IDPS) are primarily focused on identifying possible incidents, logging information about them, and reporting attempts. In addition, organizations use IDPSes for

  other purposes, such as identifying problems with security policies, documenting existing threats and deterring individuals from violating security policies.

  An IDS is not used to prevent SQL Injection attacks. Therefore this answer is incorrect.

  D: A firewall is used to restrict the flow of traffic between subnets based on rules that specify what source/destination IP addresses, ports and protocols are allowed. A firewall is not used to prevent SQL Injection attacks. Therefore this answer

  is incorrect.

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

• Question 230:

  Pete, the security administrator, has been notified by the IDS that the company website is under attack. Analysis of the web logs show the following string, indicating a user is trying to post a comment on the public bulletin board.

  INSERT INTO message `

  This is an example of which of the following?

  A. XSS attack

  B. XML injection attack

  C. Buffer overflow attack

  D. SQL injection attack

  Correct Answer: A

  The tags indicate that script is being inserted. 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.

  Incorrect Answers:

  B: When a web user takes advantage of a weakness with SQL by entering values that they should not, it is known as a SQL injection attack. Similarly, when the user enters values that query XML (known as XPath) with values that take advantage of exploits, it is known as an XML injection attack. XPath works in a similar manner to SQL, except that it does not have the same levels of access control, and taking advantage of weaknesses within can return entire documents. The best way to prevent XML injection attacks is to filter the user's input and sanitize it to make certain that it does not cause XPath to return more data than it should. The code in this question is not XML code. Therefore, this answer is incorrect.

  C: A buffer overflow occurs when a program or process tries to store more data in a buffer (temporary data storage area) than it was intended to hold. Since buffers are created to contain a finite amount of data, the extra information - which has to go somewhere - can overflow into adjacent buffers, corrupting or overwriting the valid data held in them. Although it may occur accidentally through programming error, buffer overflow is an increasingly common type of security attack on data integrity. In buffer overflow attacks, the extra data may contain codes designed to trigger specific actions, in effect sending new instructions to the attacked computer that could, for example, damage the user's files, change data, or disclose confidential information. Buffer overflow attacks are said to have arisen because the C programming language supplied the framework, and poor programming practices supplied the vulnerability. This is not what is described in the question. Therefore, this answer is incorrect.

  D: 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. SQL Injection is not used to attempt to post a comment on the public bulletin board. Therefore this answer is incorrect.

  References: http://en.wikipedia.org/wiki/Cross-site_scripting Dulaney, Emmett and Chuck Eastton, CompTIA Security+ Study Guide, Sixth Edition, Sybex, Indianapolis, 2014, p 337 http://searchsecurity.techtarget.com/definition/buffer-overflow http://en.wikipedia.org/wiki/SQL_injection