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How to find column names in SQL injection?
1 AND 1=2 UNION SELECT table_name, column_name, 1 FROM information_schema.columns Query generated. SELECT name, description, price FROM products WHERE category= 1 AND 1=2 UNION SELECT table_name, column_name, 1 FROM information_schema.columns
How to extract information using a SQL injection on PHP?
Now that you know the correct number of columns, you can go a step forward and inject a command like this one: If you had three columns, you would do SELECT 1,2,3, for five columns SELECT 1,2,3,4,5, etc.
How to inject order by clause in SQL?
The first one is to inject an ORDER BY clause indicating a column number. Given the column number specified is greater than the number of columns in the SELECT statement, an error will be returned. Otherwise, the results will be sorted by the column mentioned. Let’s see both cases. User input.
Why do we use null in SQL injection?
The reason for using NULL as the values returned from the injected SELECT query is that the data types in each column must be compatible between the original and the injected queries. Since NULL is convertible to every commonly used data type, using NULL maximizes the chance that the payload will succeed when the column count is correct.
When does SQL injection cause a database error?
If the data type of a column is not compatible with string data, the injected query will cause a database error, such as: If an error does not occur, and the application’s response contains some additional content including the injected string value, then the relevant column is suitable for retrieving string data.
When to use Union select in SQL injection?
What is union select? When an application is vulnerable to SQL injection and the results of the query are returned within the application’s responses, the UNION keyword can be used to retrieve data from other tables within the database. This results in an SQL injection UNION attack.
When to use backticks around field names in SQL?
Lastly, it allows you to use whatever field name you wish when designing your table. Sometimes it makes a lot of sense to name a field “key”, “order”, or “values”… all of which require backticks when referring to them. Backticks aren’t part of standard ANSI SQL.
Do you use backticks to avoid SQL injection?
If you avoid bad practices you don’t care, but… in real word, sometimes they are a decent way to avoid SQL injections. They are not standard and usually not portable.
Is it bad to remove backticks from table names?
However, as long as you don’t use a backtick as part of an identifier (which is the worst practice I am able to imagine), you can port your query by automatically removing backticks. If some of your query come from Access, they may quote table names with ” (and maybe you can’t remove all the ” blindly).