Found 'OR 1=1/* sql injection in my newsletter database

Question

I found the following in the "e-mail" field of my newsletter subscriber database: ' OR 1=1/*

I know it's a SQL injection, but that's it. I've googled it a little bit, but I'm still on clear on what exactly it's trying to achieve. This occurred early Nov, and to my knowledge we had no outages around that time. Can any of you kind souls tell me what this guy was probably trying and do? Is there any way to know whether he achieved what he was trying to do?

I know virtually nothing about this and I'm worried. :(

Answer 1

'OR 1=1 is an attempt to make a query succeed no matter what
The /* is an attempt to start a multiline comment so the rest of the query is ignored.

An example would be

SELECT userid  FROM users  WHERE username = ''OR 1=1/*'      AND password = ''     AND domain = '' 

As you can see if you were to populate the username field without escaping the ' no matter what credentials the user passes in the query would return all userids in the system likely granting access to the attacker (possibly admin access if admin is your first user). You will also notice the remainder of the query would be commented out because of the /* including the real '.

The fact that you can see the value in your database means that it was escaped and that particular attack did not succeed. However, you should investigate if any other attempts were made.

Answer 2

It probably aimed to select all the informations in your table. If you use this kind of query (for example in PHP) :

mysql_query("SELECT * FROM newsletter WHERE email = '$email'"); 

The email ' OR 1=1/* will give this kind of query :

mysql_query("SELECT * FROM newsletter WHERE email = '' OR 1=1/*"); 

So it selects all the rows (because 1=1 is always true and the rest of the query is 'commented'). But it was not successful

• if strings used in your queries are escaped
• if you don't display all the queries results on a page...