SQL injection attacks nowadays are rising up by a huge mark in the cyber
world, making a huge number of web sites and web applications its poor victims.
Few years back the SQL injection attacks were not much in news but, now they
have come to top the web’s vulnerabilities chart.
SQL injection attacks have
emerged as a popular and notorious means for harming the security of the
websites and web applications.
Actually how exactly an SQL injection attack come
in to affect?
- In a typical SQL injection attack, some statements written in SQL
language serve as input to a web form.
- This is done in order to obtain a web
site or application that will carry out operations on the targeted data base.
- Such fake obtained web sites via the SQL injections are often badly designed.
- The attacker employs this badly designed web site to get the access to the private
data base contents.
- It is a kind of code injection technique and that is often set
for exploiting the security vulnerability in the software of the web site or
web application.
When does an injection attack occurs?
1. Incorrect
filtering of the input by the user for entering the escape characters in string
literals which are embedded in the vicious SQL statements. Here then emerges a
scope for the potential manipulation of SQL statements which is done by the end
user who is using the data base.
2. The unexpected
execution or running of the input entered by the user that has not been
strongly typed. This is commonly referred to as incorrect type handling. The
constraints are then left unchecked.
Approaches of Inference SQL Injection Attack
The SQL inference injection attacks are usually used for mining of data. There are 3 approaches that are used for data mining following inference SQL:
1. In band
approach: The in band approach involves the extraction of data via an already
existing path between the application and the attacker. For example, returning
the data in a well rendered error message or web page.
2. Out of band
approach: The out of band approach involves the creation a new path between the
application and the attacker. This is actually worked out by establishing a
connection between the data base server and the client by employing a network
function such as HTTP, data base connection, e mail and so on.
3. Inference: Inference
does not involve any direct transfer of any actual data rather the value of the
data is inferred directly by calculating the differences between the responses
from the attacker as well as the application. This is generally done by
revoking several questions. Deliberate differences between the two responses
are generated based up on the answers to the revoked questions.
About the Inference SQL Injection Attack
2.Making use of these properties, it enables the attacker for correctly
inferring the data values.
3.Inference SQL injection has proven to be a great
mile when it comes to the extraction of the data using SQL injections.
4.It came
to be extremely useful when the other two methods for data retrieval i.e., in
band and out of band didn’t prove to be successful.
5.The inference SQL attacks
only affect the SQL servers and they are quite slow due to time delay.
6.Since
2002 no remarkable improvements have been witnessed in the field of inference
SQL.
7.The inference SQL injection attacks have an added advantage which is that
they can be employed in any SQL injection situation.
8.When a specific query is
injected in to an ADQ (application defined query), the web server generates a
response code depending up on the data values.
9.It is quite common for an attacker
to initially look for exploiting the SQL injection vulnerability by using the
in band results.
10.But this not feasible every time since in some situations time
is the major factor, in such situations out of band or inference methods are
deployed.
11.Not only data, but logic can also be inserted in to the query of the
application.
12.In this the output of the application can be controlled and based
on this output the stored values can be inferred from the data base.
13.The
creation of an SQL inference attack is based on the sophistication of the
information that the attacker has regarding it beforehand.
14.The inference SQL
attack through the web server response codes present a major problem which is
that they can be quite easily be detected by the good web server
administrators.
15.But, the attackers are so clever that they have figured out
another such inference attack called content manipulation inference attack.
16.Using this, they are able to keep the response code constant while
simultaneously changing the web site content.
