Anything that can be seen in the source is as vulnerable as what is openly displayed. To test the vulnerability, the hacker often starts with the most common vulnerability: the single quote or apostrophe character.
This character is the string literal delimiter in SQL. If user input is submitted directly to the back-end server without sufficient validation or scrubbing, it then becomes incredibly easy to gain control of the DBMS. If the hacker is working with a hidden field in the source, it's only a tiny bit more complicated in that the source needs to be downloaded from the site and saved.
Then the URL and the hidden field need to be modified, and the source executed. If this is a true vulnerability, the additional information after the apostrophe will be treated as a part of the query string submitted to the SQL server and will be executed by the back end. If a hacker knows what to look for, error pages are a great tool to diagnose and refine hacking attempts because of the information they can provide.
These errors are generated by the database system, and that means the single quote inserted in the prior step was successfully passed to the back-end database. If the hacker gets a different error, he will then look carefully through the source of the error page for any references to "SQL Server", "ODBC", or "syntax". Sometimes the details of the error are hidden in the headers or in comments that are only visible in the source. If an error page is returned that includes links, the hacker will search the links to see if there are more error details.
If a " Page Redirect" is called, the hacker will try to capture the page he is redirected from. This may have more error details in it that can't be easily read before the redirect occurs. If a " error page" is returned, the hacker knows that the injection may have been successful as this is the default error page for most Web servers.
Though the hacker may not be able to determine much from this page, it will encourage greater attempts to exploit this possible weakness. The hacker will continue to try other options for bypassing the site's validation and scrubbing routines, in each case carefully examining the server's response.
These attempts include:. You may need to allow the user to enter potentially injurious characters into a textbox. For example, users may need to enter a single quote or apostrophe as part of a person's name. In such cases, you can render the single quote harmless by using a regular expression or the String. Replace method to replace each instance of the single quote with two single quotes.
For example:. The code in Figure 5 employs parameterized SQL to stop injection attacks. This might be necessary if your IT department doesn't believe in stored procedures or uses a product such as MySQL which didn't support them until version 5. If at all possible, however, you should employ stored procedures for the added ability to remove all permissions to the base tables in the database and thus remove the ability to create queries like the one shown in Figure 3.
One of the bad practices demonstrated in BadLogin. Here's the connection string, which can be found in Web. This account runs under the System Administrators role which means it is allowed to do just about anything—creating logins and dropping databases are just a few. Suffice it to say, it is a very bad idea to be using the sa or any high-privileged account for application database access.
It is a much better idea to create a limited access account and use that instead. The account used in GoodLogin. The SQL injection attack shown in Figure 3 resulted in the display of user names and passwords from the Users table. This sort of table is commonly used when employing forms authentication, and in many applications the passwords are stored as clear text.
A better alternative is to store encrypted or hashed passwords in the database. An attacker who is able to force statement truncation by passing unexpectedly long strings to a stored procedure can manipulate the result. For example, the stored procedure that is created by the following script is vulnerable to injection enabled by truncation.
By passing characters into a character buffer, an attacker can set a new password for sa without knowing the old password. The stored procedure that is created in the following example shows what can happen. Therefore, the following statement will set the passwords of all users to the value that was passed in the previous code. Otherwise, you can calculate the required buffer size as follows. The following example shows this. When you are concatenating values of type sysname, you should use temporary variables large enough to hold the maximum characters per value.
Otherwise, you can calculate the required buffer size as explained in the previous section. Skip to main content. This browser is no longer supported. Download Microsoft Edge More info.
Contents Exit focus mode. Is this page helpful? Please rate your experience Yes No. Any additional feedback? Submit and view feedback for This product This page. View all page feedback. In this article. Single-line comment delimiter. If our input is being parsed as part of the query, we can control it using SQL commands.
If we can control the query, we can control the results. We want to get access to the administration area of the website. First, we need to find out how many columns the current table has. We will use column ordering to achieve that. You can order either by column name or by the number of the column.
In this case, we need to use the number of the column. If the number that we pass in the parameter is less than the total number of columns in the current table, the output of the application should not change because the SQL query is valid.
However, if the number is larger than the total number of columns, we will get an error because there is no such column. In our case, we have identified 10 columns:. Now that we know how many columns the current table has, we will use UNION to see which column is vulnerable. The vulnerable column is the one whose data is being displayed on the page. We can confirm this by replacing it with version which will show the MySQL version:. The database function returns the name of the current database.
To find the password for this hash, we will use a well-known password recovery software named hashcat. This software offers various methods of cracking a password.
We will try a dictionary attack with a relatively small list containing 96 million passwords. Once we do that, the options are limitless. There are third-party WordPress plugins that could allow us to execute shell commands or upload new files. They have thus been omitted from this example. For compatibility, they remain flipped x, the horizontal offset, is instead used for latitude, the vertical , and thus risk misleading you.
Prefer instead to use the lat and lng properties. Geometry types can also be constructed in several ways. Unlike Geographies, they are consistent in always placing x before y. Supported on SQL Server and later. You can pass a data table as a parameter to stored procedure. First, we have to create custom type in our database.
You can clear the table rows for easier batching by using table. An object returned from a sucessful basic query would look like the following. The rowsAffected variable is an array of numbers. Each number represents number of affected rows by a single statement. In addition to the rowsAffected attribute on the done event, each statement will emit the number of affected rows as it is completed. You can enable built-in JSON parser with config. Once you enable this, recordset will contain rows of parsed JS objects.
Given the same example, result will look like this:. More information about JSON support can be found in official documentation. If your queries contain output columns with identical names, the default behaviour of mssql will only return column metadata for the last column with that name.
You will also not always be able to re-assemble the order of output columns requested. You can use the arrayRowMode configuration parameter to return the row values as arrays and add a separate array of column values. When using arrayRowMode with stream enabled, the output from the recordset event as described in Streaming is returned as an array of column metadata, instead of as a keyed object.
The order of the column metadata provided by the recordset event will match the order of row values when arrayRowMode is enabled. Those errors are initialized in node-mssql module and its original stack may be cropped. You can always access original error with err. SQL Server may generate more than one error for one request so you can access preceding errors with err. Each known error has name , code and message properties.
SQL errors RequestError with err. Recordset metadata are accessible through the recordset. MAX length. Types sql. XML and sql. Variant are not supported as input parameters. This module has built-in SQL injection protection. Always use parameters or tagged template literals to pass sanitized values to your queries. Skip to content. Star 2k. MIT License. Branches Tags. Could not load branches. Could not load tags. Latest commit. Git stats commits. Failed to load latest commit information.
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