![]() Inject a series of ORDER BY clauses and increment the column index until an error or change in behavior occurs ![]() That’s why it’s important to determine the number of columns that are being returned from the original query, and they list two methods here: When performing a UNION attack, you have to match the number and data type of columns from the tables you are combining. I do recommend that you take some time reading through this reference, but I will point a few things out. One other very helpful cheat sheet by PortSwigger is specific to UNION attacks. We’ve seen most of the tips on this page, but I found the format to be quite nice so I included it here. We see tips on how to extract a database’s version, which again is helpful in figuring out vulnerabilities specific to that version. Next, we have a general list of information by PortSwigger including tricks on how to perform string concatenation, which combines strings together. There is a lot more to this article, so feel free to take a look around! In this case, each DBMS has slightly different syntax. However, if it doesn’t sleep for 5 seconds, then the database is not vulnerable to that specific attack. Then, if the database sleeps for 5 seconds, we know that it has a vulnerabilitiy. Such as using a boolean of 1=1, and causing the database to sleep for 5 seconds if it interprets that 1=1 statement. Which would log you in as the administrator user.Īnother example is using commenting syntax specific to MySQL which can be used to determine the version of MySQL being run.įurther down the page, they mention If Statements, which are a key part of performing Blind SQL injections, since we can run IF statements to trigger certain actions. SELECT * FROM members WHERE username='admin' Since - comments out everything that comes after it, SQL will interpret it as: SELECT * FROM members WHERE username='admin'-' AND password ='password' ![]() If the app were vulnerable to this injection, you could type: Let’s say you try to log in as an admin user. So as you can see, this cheat sheet is not completely comprehensive and you have to verify some of the information, but it gives us a great head start and it’s helpful reference material.Īn example of when you could use commenting for an SQL injection is listed below: On the other hand, # sign also works with MySQL. With -, they put an (SM) next to it, meaning that it works for SQL Server & MySQL, and by the way it also works for SQLite, PostgreSQL, and Oracle. But, different dabases use different commenting syntax. I won’t go through all of it for the sake of time, but they include a Table of Contents, and they also label which statements work for which database management system, like MySQL, SQL Server, PostgreSQL, and Oracle, or other databases.įor example, and one very helpful trick that we will use constantly when performing SQL injections is commenting out the rest of a query. So this is a helpful cheat sheet as a starting point.Īnother, more comprehensive list, that we will call our “Master List” is by Netsparker. ![]() The number of columns in the current tableĭisplaying database, column, and table names through the metadata table like we talked about These are some of the payloads the tool uses to test for vulnerabilities, so they are also inputs we can try to use manually.įurther down, there are other types of payloads we can try, and then there are tips on how to determine: If none of those work, we can try others.įor example, below, this author included payloads from a tool called SQLMap which we will take a look at in another lesson. If one or more of these inputs work, then we can use that to our advantage. Stacking both a union and time-delay injection The first cheat sheet we will look at includes some helpful inputs for that very purpose.Īlso uses # which is for comments, essentially causing SQL to ignore anything that would come after our injection Think of this as prodding defenses to see if there are any weaknesses. Getting started finding a vulnerable parameterĪs I mentioned in a prior lesson, one of the first steps we will need to take to test an application and database for SQL injection vulnerability is to try to get any kind of non-expected response. Getting started finding a vulnerable parameter: Luckily, many cheat sheets and reference materials exist out there to give us help, so let’s take a look at a few of them that we can continuously reference.īy the way, these are lists that I’ve found just by searching, so no paywalls or anything, just simple free resources to get us started. But, most of us are not experts in every DBMS out there, and it takes time to build up that kind of knowledge. Because there are differences in syntax, structure, and available functions depending on the DBMS that an application is using, we have to learn their various quirks in order to effectively perform SQL injections. ![]()
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