I am scanning my web application which i have build in Asp.net. Scanner is injecting junk data into the system trying to do blind Sql injection on the system but i am using Sql store procedures with parametrized quires which is escaping the blind sql injection but these junk entries are stored into the system as normal text i am sanitizing the inputs not to take ' and other sql related parameters.Now my question are
1) Are these junk entries any threat to the system?
2) Do i really need to sanitize the input if i am already using paramitrised quires with store procedures?
3) Scanner is not able to enter information into the system if u don't create login sequence is that a good thing?
Any other precautions i should take please let me know
Thanks
As you correctly mentioned, the 'junk' entries in your database are form submissions that Acunetix is submitting when testing for SQL injection, XSS and other vulnerabilities.
To answer your questions specifically:
1) No, this junk data is just an artifact of the scanner submitting forms. You might want to consider applying stricter validation on these forms though -- remember, if a scanner can input a bunch of bogus data, an automated script (or a real user for that matter) can also insert a bunch of bogus data.
Some ideas for better validation could include restricting the kind of input based on what data should be allowed in a particular field. For example, if a user is expected to input a telephone number, then there is no point allowing the user to enter alpha-characters (numbers, spaces, dashes, parenthesis and a plus sign should be enough for a phone number).
Alternatively, you may also consider using a CAPTCHA for some forms. Too many CAPTCHAs may adversely affect the user experience, so be cautious where, when and how often you make use of them.
2) If you are talking about SQL injection, no, you shouldn't need to do anything else. Parameterized queries are the proper way to avoid SQLi. However, be careful of Cross-site Scripting (XSS). Filtering characters like
<>'"is not the way to go when dealing with XSS.In order to deal with XSS, the best approach (most of the time) is to exercise Context-dependent Outbound Encoding, which basically boils-down to -- use the proper encoding based on which XSS context you're in, and encode when data is printed onto the page (i.e. do not encode when saving data to the database, encode when you are writing that data to the page). To read more about this, this is the easiest, and most complete source I've come across -- http://excess-xss.com/#xss-prevention
3) A login sequence is Acunetix's way of authenticating into your application. Without it, the scanner can not scan the internals of your app. So unless you have forms (perhaps on the customer-facing portion of your site) the scanner is not going to be able to insert any data -- Yes, this is generally a good thing :)