Malicious Injection — It's Not Just For SQL Anymore

nywanna writes "When most people think of malicious injection, they think of SQL injection. The fact is, if you are using XML documents or an LDAP directory, you are just as vulnerable to a malicious injection as you would be using SQL. Bryan Sullivan looks at the different types of malicious code injections and examines the very basics of preventing these injections."

Comments

XML Logic Is Flawed

[CowboyBob500]

In his XML example with XPath injection he states that running a certain query can return the entire order history of all customers. That may be true, but if the application is returning an XML document containing the entire order history of all customers for each customer request before running an XPath query, then I think the application has more problems than being vulnerable to XPath injection.

Bob

Re:Validate this

[thsths]

>> To be completely thorough, a developer should set up both white- and blacklists in order to cover all bases.
> I can't help but feel that most developers have at least a little common sense and do something along those lines anyway.

I hope that most developers have the common sense to take the correct approach: avoid injection problems by proper quoting! There is no need to validate the data, you just have to make sure that it stays data when you parse it on. Just use the proper library functions, and you will be fine (especially if you use hex encoding :-)).

White lists are a good idea if you don't trust you quoting, or if you need to verify the input for another reason. Black lists are most certainly not a good idea. Just imagine that the web shop tries to sell a product called "Selecta[tm]", but you block all attempts to buy it because it matches your black word "SELECT" :-(

P.S.: Anybody with an apostrophe in their name naturally develops an unsatisfiable urge to kill web programmers.