Fully answer all of the following questions using complete sentences and proper
ID: 3592832 • Letter: F
Question
Fully answer all of the following questions using complete sentences and proper English grammar, punctuation, and spelling.
1) Provide an example of a Cross Site Scripting (XSS) attack. Include an explanation of the differences between stored and reflective XSS attacks.
2) Provide an example of a SQL Injection attack. Why does the back end database make a difference in how it works? What type of information or access could be compromised with SQL injection attacks? Include at least one additional reference
3) Watch this video on “Ethical Hacking - How Buffer Overflow Attacks Work”: https://www.youtube.com/watch?v=iZTilLGAcFQ. In your own words, explain how Buffer Overflow attacks work. Include at least one image or drawing. Include at least one additional reference.
4) Both the SANS (http://www.sans.org/top25-software-errors/) and OWASP (https://www.owasp.org/index.php/Category:OWASP_Top_Ten_Project) sites provide techniques for preventing application attacks. Discuss three of these.
5) What part of the e-mail process does SSL/TLS usually secure? Is this end-to-end security? Explain. What standards and technologies provide end-to-end security?
Explanation / Answer
SQL injection is a code injection technique, used to attack data-driven applications, in which nefarious SQL statements are inserted into an entry field for execution (e.g. to dump the database contents to the attacker).[1] 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 attacks allow attackers to spoof identity, tamper with existing data, cause repudiation issues such as voiding transactions or changing balances, allow the complete disclosure of all data on the system, destroy the data or make it otherwise unavailable, and become administrators of the database server.
This form of SQL injection occurs when user input is not filtered for escape characters and is then passed into an SQL statement. This results in the potential manipulation of the statements performed on the database by the end-user of the application.
The following line of code illustrates this vulnerability:
This SQL code is designed to pull up the records of the specified username from its table of users. However, if the "userName" variable is crafted in a specific way by a malicious user, the SQL statement may do more than the code author intended. For example, setting the "userName" variable as:
or using comments to even block the rest of the query (there are three types of SQL comments[13]). All three lines have a space at the end:
renders one of the following SQL statements by the parent language:
If this code were to be used in an authentication procedure then this example could be used to force the selection of every data field (*) from all users rather than from one specific user name as the coder intended, because the evaluation of '1'='1' is always true (short-circuit evaluation).
The following value of "userName" in the statement below would cause the deletion of the "users" table as well as the selection of all data from the "userinfo" table (in essence revealing the information of every user), using an API that allows multiple statements:
This input renders the final SQL statement as follows and specified:
While most SQL server implementations allow multiple statements to be executed with one call in this way, some SQL APIs such as PHP's mysql_query() function do not allow this for security reasons. This prevents attackers from injecting entirely separate queries, but doesn't stop them from modifying queries.
Incorrect type handling
This form of SQL injection occurs when a user-supplied field is not strongly typed or is not checked for type constraints. This could take place when a numeric field is to be used in a SQL statement, but the programmer makes no checks to validate that the user supplied input is numeric. For example:
It is clear from this statement that the author intended a_variable to be a number correlating to the "id" field. However, if it is in fact a string then the end-user may manipulate the statement as they choose, thereby bypassing the need for escape characters. For example, setting a_variable to
will drop (delete) the "users" table from the database, since the SQL becomes:
Blind SQL injection
Blind SQL Injection is used when a web application is vulnerable to an SQL injection but the results of the injection are not visible to the attacker. The page with the vulnerability may not be one that displays data but will display differently depending on the results of a logical statement injected into the legitimate SQL statement called for that page. This type of attack has traditionally been considered time-intensive because a new statement needed to be crafted for each bit recovered, and depending on its structure, the attack may consist of many unsuccessful requests. Recent advancements have allowed each request to recover multiple bits, with no unsuccessful requests, allowing for more consistent and efficient extraction. [14] There are several tools that can automate these attacks once the location of the vulnerability and the target information has been established.[15]
Conditional responses
One type of blind SQL injection forces the database to evaluate a logical statement on an ordinary application screen. As an example, a book review website uses a query string to determine which book review to display. So the URL http://books.example.com/showReview.php?ID=5 would cause the server to run the query
from which it would populate the review page with data from the review with ID 5, stored in the table bookreviews. The query happens completely on the server; the user does not know the names of the database, table, or fields, nor does the user know the query string. The user only sees that the above URL returns a book review. A hacker can load the URLs http://books.example.com/showReview.php?ID=5 OR 1=1 and http://books.example.com/showReview.php?ID=5 AND 1=2, which may result in queries
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