Anatomy of a SQL Injection Attack

Trailrunner7 writes "SQL injection has become perhaps the most widely used technique for compromising Web applications, thanks to both its relative simplicity and high success rate. It's not often that outsiders get a look at the way these attacks work, but a well-known researcher is providing just that. Rafal Los showed a skeptical group of executives just how quickly he could compromise one of their sites using SQL injection, and in the process found that the site had already been hacked and was serving the Zeus Trojan to visitors." Los's original blog post has more and better illustrations, too.

Comments

Re:Use a persistence library

[AuMatar]

Persistence is just a bad idea, it hides the real performance issues of how databases work, and limits how you can easily manipulate the data. A better idea is just to always use bind variables. Problem solved.

Aarghhhh

[boner]

I for one am sick and tired of these types of attack. Whoever, in their right mind thought it was a good idea to expose SQL query inputs on the Web?

Ever heard of input sanity checking? It was very popular in the say, 60's, 70's and 80's. It means you reject fields you don't expect to be there, instead of arbitrarily passing them onto the backend database. These types of attacks illustrate what is wrong with web security: developer convenience trumps common sense everytime...

Next time we see Ballmer hopping along shouting developers, maybe could he please add the words 'SECURITY BY DESIGN', please, pretty please?

SQL injection attacks are asinine because they are so prevalent, easy for the hackers AND easy to fix. We should name and shame every site, and every web-application stack that allows these attacks to take place.

nuf said.

Re:Aarghhhh

[xtracto]

Then what needs to be done is make the libraries have this security implemented *by design*.

That is, the only possible way to get or insert data from a database should be the correct one. Security should be an enforced feature of the library (PHP, Java, etc).

It is kind of like "accessibility", it is available there (at least say, in Java and Flash) but *because* it is not compulsory, very few programmers implement it.

Re:Aarghhhh

[ZeroExistenZ]

developer convenience trumps common sense everytime

You're clearly not writing software for a living...

There are a few things more important than security: time to delivery and budget.

Colour this with unrealistic expecations and you get situations like these:
"What's your estimate?" *honest assessment* "Ok, so if you work harder, you can do it in less time right? (all programmers are soo lazy.. I read that somewhere)"
"Well, it depends on what I encounter while bringing this analysis into reality..."
"Just make it work so we have something to show for by date xx-xx-xxxx"
^

Even in large coorperations with large budgets, the smaller one's usually are more idealistic but are on a tight budget.

Because alot of developers are struggling with getting the "damn thing to work", and there are so many shifts in deadlines, "security", as a seperate item, often is neglected because people are relieved they're having something "up and running".

I do agree though, that initial design and architecture should be welldefined and requires extra attention with security measures and considerations built-in, whereas many developers are running around with such a sense of urgency and pressure they just want to get to "coding thing" instead of thinking first what and how they'll code it, yet it doesn't change or improve the environment and pressure which results in these things.

Re:Aarghhhh

[l0b0]

Ever heard of input sanity checking?

Yep, it's that enormously annoying thing that almost no developers get right. They filter out emails that contain + or -, names with accents, and zip codes / phone numbers for other countries. You should never reject a value from a user: If it looks wrong to you, suggest that they change it, but for f's sake put it in your DB. And don't tell me about quotes or backspaces - RTFM or Google it.

Re:Aarghhhh

[ZeroExistenZ]

They don't understand any of the implications of what they are doing and only know how to take results from a database and display it in a nice looking web page.

Well, there are many like that, and in essence that's webdevelopment, right?

Consider an application where you can control the logical flow, you need to know your basic language and your GUI's behave the way you expect. Done.

Now, for being a webdeveloper you need to know HTML, XHTML, CSS, JavaScript, PHP, MySQL, MS SQL, .NET (preferably working knowledge of 3.5 and playing around with WCF/WPF), AJAX-concepts and implementation, various toolkits and libraries in place, XML, XSLT, JSON, WebServices, COM+ interaction, and need strong afinity around security concepts and be aware of injection methods, sniffing, current state of hashing algorithms, make sense of server technology and scaling (if your server is in fumes, you need to kickstart it) so that extends to IIS, Apache. If you're going more the el cheapo/opensource approach, it's mostly a box running Apache, MySQL and PHP (for which you need to subtle differences through different releases) often Mediawiki too, so you'll need to find your way around a Linux station and often are deploying and setting up such a box ad hoc as well... It adds up quite fast if you've consulted a bit and in each environment encounter different setups, architectures and approaches.

"Web development" has gotten pretty involving to get the pretty display, for which there isn't really a good methodology anymore as the web has evolved in such a way the "hypertext markup" combined with "style sheets" sortof feels dated. (that's why you have XAML, Flash, Flex, .. trying to solve the problem adding to complexity).

I do agree; webdev is pulling data and storing data while showing it in a pretty way, modify the page based on that and have a fluid user experience. However, those lasts are pretty difficult if there's a clear idea about the result and you need to depend on external parties (IE bugs, FF bugs, toolkits bugs, API frameworks with bugs, ...) to get your thing done.

I think webdevs are the gluers between all these frameworks and layers, there's maybe not much writing logic, but trying to make sense of the mess and compiling and stringing very specific technologies (legacy or hyped new) together in order to have a functional and pleasing result.

It's odd to me that there's a general looking down on webdevelopers, not just from non-techies, but also from techies whoe feel their work is "so much more significant" because "they have to think more and aren't a code monkey", yet wouldn't survive in an unstructured choatic environment where you have to think on your feet and act quick when things fall out and can't have flow in a straight line (say "I'll write function x and y today, and nobody will bother me all day while I do so") but are constantly interrupted or required to take some action, asap and efficient, while you're juggling a dosen projects, maintaining another handful and are trying to please clients. Plus ofcourse, get new projects worked out, writing analyses and following up/leading communication of 3rd parties in order "to hook up that webservice the client wanted to implement" and god knows what.

But yes, it's just displaying stuff on a page, right? I can show you complex systems (webbased stockmarket software fe.) which makes your head spin and cry in desperation (I've seen some break up and give up on the legacy mess), yet it's all "just showing data in pretty boxes" and "pulling it from a datasource" (stock market floor) and "saving it" (processing orders with business rules and automating processing of orders all within legal limitations) all to meticious specification of the clients, all with their own perculior wishes?

"But they are the lazy programmers and we don't know what the hell they are doing, but they have no concept of the implications of their work, sir.". Put

Re:Aarghhhh

[gmack]

The problem is not the web devs it's the managers who didn't realize they need both a programmer and a webdev.

They are very different functions. If you have only webdevs you tend towards the sort of security mess we are seeing here. If you have only programmers you end up with a site that is butt ugly and useless from a user interface perspective.

Your stock market display software is a good example of a case where the entire project will fall apart unless you have programmers who can move the data efficiently and securely and then some skilled webdevs to handle the user interface work.

Re:Use a persistence library

[mk_is_here]

A more simple way is to use a parametrized statement. No extra libraries if you are using Java, .NET, or PHP5.

Comment removed

[account_deleted]

Comment removed based on user account deletion

SQL Injections SHOULD NEVER WORK

[mcalwell]

If your code is running at the correct privilege level, SQL injections should be completely irrelevant.

If your user is connecting with the correct credentials, they should only be able to see public data and their own records, nothing else.

This is implemented by using views in the database, and only allowing users rights to views, not tables.

If your website user is connecting with credentials that allow a crafted SQL query to see priveleged data, you have set everything up wrong

If you have set everything up correctly, even a successful SQL injection will only return data the user can see

Re:limit the length and content of what you accept

[pedestrian crossing]

Unless you are trying to put Chris O'Connor into your database, and his name must be spelled correctly...

didn't you ever watch startrek?

[Colin Smith]

learn from Scotty. always double your estimates... Especially when they ask for an honest estimate.

I'm up to a multiple of 16 now.

 

Re:Use a persistence library

[ShannaraFan]

Putting the logic in stored procedures allows ME, the DBA, the guy with the SQL know-how, to tune the gawd-awful query that you, the pointy-clicky .NET monkey, is using to bring my server to its knees. NINE left joins again subqueries, each with a GROUP BY, then another GROUP BY applied over the query as a whole? WTF are you thinking? Fixing your code requires a new build & deployment cycle. Fixing a stored proc, I can do that with a simple DROP/CREATE script.

Yes, I'm bitter. I'm surrounded by pointy-clicky types who insist on procedural thinking when writing queries. Set theory? What's that?

This lovely programmer has sold his code around

[Trailer Trash]

Took me 2 minutes with Google to find other sites that are apparently using the same crappy code with the same vulnerabilities. "inurl:" does wonders.