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  • >> MING CHOW: Good afternoon, everyone. My name is Ming Chow and I will be speaking today

  • about NoSQL databases. How people here are using a NoSQL database such as Mongo, Redis,

  • Cassandra, many, many, to name. How is your experience so far with them?

  • >> AUDIENCE MEMBER: Good. >> MING CHOW: Yeah, so far, so good. They

  • are fast. They are transactional. They are very easy to use. You don't need SQL to use

  • them. You know, and if you want to insert data, search for stuff, it's all based on

  • the computer science principle of key value pairs. Okay? So if you have never seen a Mongo

  • database or a NoSQL database, typically how you want to find data is I'm connected to

  • a financial news database on Mongo right now, but if you want to find something, it's going

  • to be something like the database, the name of the collection, then the find routine,

  • and typically, it would take in JSON. So the key is going to be screen name, let's say

  • for the screen name is going to be CBS News. Okay? So what I'm going to do here, just a

  • very simple example is to show how you find all financial news that's from CBS News on

  • Twitter. And so what happens is those are all of your results. Okay?

  • So really nice and easy, but that's only just one way, one of many ways to search for stuff

  • in a NoSQL database such as Mongo. What about security of NoSQL databases? That's another

  • story. That's all over the place. Right now we have a mixture of heterogeneous

  • and homogenous security issues and that's what I'm here to talk about. Okay?

  • I'm actually very surprised that the topic of just NoSQL databases has never, ever been

  • covered here at DEF CON. Two years ago, I talked about building, you know, the issues

  • of using HTML 5, which is the application side. There's a lot to just the database side

  • of things and a lot has changed in two years. One thing that hasn't changed is we're all

  • still new to NoSQL databases. You know, we're all new to this, and the only thing largely

  • a lot of us care about is just making it work. Just making it work. And, of course, that

  • certainly ‑‑ that has some, you know ‑‑ you know how usually that goes, especially

  • if you leave security into the hands of developers. So a homogenous problem, a very simple one

  • right off the bat, if you know database vendor, you know the IP address, you know the port

  • number. You have almost won the game. Okay? Why? Why is it just knowing just the IP address,

  • the database vendor and the port number is good enough? That's because of this next thing,

  • which is authentication and encryption. It's almost nonexistent or extremely weak.

  • If you use many ‑‑ if not all NoSQL databases out there, if you take them out of the box,

  • you take them out of the box, and administrative user, authentication turned off. Turned off.

  • Okay? Even if they do support features such as encryption

  • and auditing, not only do you have to turn them on yourselves, but also, the scheme is

  • really weak. Because for example, among still uses MD5 in CouchDB. If you ever read the

  • documentation of Mongo or Couch or Redis or Cassandra. We urge you to use this database

  • system on a trusted environment. (Chuckles).

  • That's from the documentation. Just read the documentation. It's quite mind boggling. Security

  • is a complete after thought. How big is ‑‑ how big is NoSQL databases out there. If you

  • do a search on Shodan, it's 40,000 instances of Mongo that are out there, it has and there

  • are also 20,000 instances of Redis running. So it's a big deal!

  • It's already there. So this is a ‑‑ these are homogenous issues that we have seen that

  • affects all NoSQL databases. Okay. So there's a lot of chatter on this thing known as ‑‑

  • okay. NoSQL ‑‑ not only do I not need to know SQL anymore, but this whole problem

  • that I think you guys might have heard of called SQL injection goes away.

  • Actually, in my humble opinion, the injection problem has gotten worse. Okay? Now, okay,

  • sure SQL injection is gone, but now we have three ‑‑ I say three different classes

  • of injection attacks. Okay. One is called schema. Now, NoSQL databases, how they work,

  • they are based off of dynamic data model. Okay?

  • If you insert a record or if you create a ‑‑ if you create a database that doesn't exist,

  • automatically create it for you, right on the fly. Okay?

  • Yeah, it goes back to the original point that the NoSQL databases are really, really easy

  • to use. It's very, very flexible. That's a good thing. Of course, a bad thing is, you

  • know, you have flexible dynamic record and data entry. Also, if you can easily overwrite

  • existing values for keys, very, very simply, last key wins. Okay?

  • So I'm going to show you a few demos. Schema I will do last. You can do query, with many

  • unsaved queries very simply by string concatenation and now this gem. I love this one. How many

  • people are good at JavaScript here? Okay. Learn it! Okay. Learn it! It ‑‑

  • now a lot of these NoSQL databases, they have taken JavaScript functions as parameters to

  • search and insert okay? And I will give you an example of using the where clause.

  • Now, here, I am now going to give a quick demo on ‑‑ hopefully this works.

  • Okay. Search by handle. So what I have done in this example is I have created a new search

  • system, okay? There's a whole bunch of Twitter handles that I use by the Bloomberg terminal

  • and I have actually stored 4,000 tweets in all. But let's say that I know that one of

  • the Twitters on the Bloomberg handle is venture beat. I type in venture beat and hit search.

  • This is a collection of all the news that's returned by venture beat, that has been tweeted

  • out by venture beat for, I don't know, a few days. Okay?

  • All right. Works well. CBS News. And so we have found 208 items. Okay?

  • Now, how can we beat this system? One thing is, what we can do, if you want to see more

  • records than you want, okay, and PHP is a very interesting beast working with Mongo

  • databases. Let's put in for this query parameters known as search box, we add square brackets,

  • dollar sign and E. And dollar sign and E in Mongo, means not equal to. You can use dollar

  • sign and E to search for things that are not equal for something. What PHP does, any inputs

  • that are within square brackets, they are automatically converted to an associate format.

  • How will you read this is, okay ‑‑ so what this now ‑‑ this query will do,

  • the original stuff I showed you was, okay, give me everything that is CBS News or venture

  • beat. Now, what we just did is we just modified the query and we just changed it on the fly

  • and we said, okay, give me everything that is not equal to CBS News. Hit enter.

  • Now, we have all of these records, all of these news items that are from sources on

  • Twitter that are not CBS News. Okay? We have returned back everything. So what's the culprit

  • here? What's the culprit? So if I can show you the source, search by handle.php, and

  • I'm going to show you the line, that one right there, "collection find array, search for

  • screen name equals something." Now remember what I said, if you use square brackets for

  • your query parameters those things will be in ‑‑ that will be translated into an

  • associative array. What this will do will be the associated array

  • will be screen name, arrow and the value will be in an array, an associative ray format.

  • Not equal to as the operator and what did I use? I think I used CBS News. Okay?

  • Now I'm going to show you an example of JavaScript injection. Okay? Search "hack me.php."

  • Very, really plain looking box here. What you can't do ‑‑ I didn't give any directions

  • on how to use this, but what we can do is this. We can actually use JavaScript functions.

  • We will type in a few JavaScript functions. Function. Okay. Now let's say I want to return

  • all the news items from, let's say NBC News. So we return this.screen name equals, equals

  • and the string is going to be NBC News. Okay? Semicolon, close the statement, close the

  • function and here we go. Return. Okay. This is what it's going to do.

  • It will return all the news items that are from CBS News. But this is using JavaScript.

  • Let's do one more. Let's do one more, which is pretty nice which is going to be function.

  • Okay. Let's see if we get everything. Can we also do other mangling using JavaScript

  • as well too? Sure! Why not? How about this one, this. Okay. Return this.text.we

  • can do a regular expression matching. Okay? What we are going to search for is Apple.

  • What this is going to do ‑‑ it's going to search for all the news items. All 4,000

  • plus records. Anything that has the word "apple" in them. Okay?

  • Let's do some even more crazier things. We can also do this, function while one print

  • more. Actually, I will put this in ‑‑ what this is going to do ‑‑ oops. Did

  • I close? Nope. I'm missing one more. All right. Going. It's going. I'm going to stop this.

  • You don't need this anymore. But what I can show you is this. If I SSH into the box, okay,

  • probably going to get a password error. Oh, I didn't. Okay. CD/var/log. CDmongo db. See

  • what did in Mongo in logs and more Mongo db.log. Oh, I don't like that.

  • How about this one, how about tail. That was from ‑‑ you know, this is one

  • result of using ‑‑ well, what you can do with, well ‑‑ if your query is based

  • on ‑‑ in your injection is a JavaScript function.

  • Now, I only have 20 minutes for this whole talk. What if you do this instead of PHP,

  • if you use something like node, JS and express. Okay?

  • Now, let's go back to the schema attacks. How about this one. I like this. I've got

  • to show you this. So right now the server is at 19%. But what

  • if ‑‑ what if ‑‑ if I run the script that I created using Ruby, okay, one of the

  • nice byproducts, okay ‑‑ one of the nice byproducts of all of this, of schema attack,

  • you know, of this whole dynamic model, okay, what it's going to do, I'm going to open up

  • a word list of ‑‑ a Word list file, okay? And it's going to create a brand new database

  • for each and every word in this file. One nice byproduct is you can exhaust the system

  • resources on the server take up 100% of the space. Okay? So if you take a look, now ‑‑

  • oops. Not yet. Okay. We'll let this thing run. Let this thing

  • run. Okay? All right. Heterogenous problems. Now, how many NoSQL databases there are? Too

  • many to name. Different database systems, different NoSQL database systems and you are

  • also dealing with different sets of term non, for example, Mongo, the whole idea of a table

  • is a collection and the whole idea of a record is a document. It's completely different than

  • Cassandra and Redis is just key value pairs and how about the results? I know different

  • systems like, for example, CouchDB, they support different sets of outputs as well. Outputs

  • that you can use JSON and binary JSON. What does it have to do with anything security?

  • This infers this problem known as complexity. Now, in order to really understand the problem

  • of NoSQL, you need to each and every documentation. Different systems, different features, different

  • inputs and different outputs. Even MongoDB, some vendor specific items, MongoDB, Mongo

  • DB, is tied to all the different interfaces. You can take a look at some really cool startup

  • lab data and this local collection, okay? CouchDB, HTTP is actually opened by default.

  • All right. So how do you actually protect yourself from ‑‑ so what does this all

  • mean? How do you secure the NoSQL databases. It relies on the full perimeter security.

  • It's really, really important. Okay? Configuration, if you want to make NoSQL databases

  • work right, configuration is very important. You can't just take it out of box and sit

  • back and use it right away. The whole issue of validation becomes very important. Not

  • only are you validating inputs now. You have more things to validate in terms of inputs,

  • including JavaScript functions. Hey, for output, you also have to validate the binary JSON

  • and JSON as well. So validation becomes even more critical.

  • What does it all mean? Look, back in the good old days, the only game in town were Oracle,

  • my SQL and you can build any applications using that thing now. But now they are not

  • the only games in town and you have systems such as Mongo, Redis, Couch. You've got to

  • use the right database for the right job, for the right application. Okay?

  • Yeah, so not only did you ‑‑ okay is so you can't just assume that SQL injection

  • has gone away. In fact, there are many, many more opportunities depending on what database

  • system that you choose. But the thing that really, really bugged the living hell out

  • of me, of these things, right now NoSQL databases are completely brand new but we have a problem

  • right now with, A, we have technologies completely deployed naively. They are just out there.

  • Especially if you believe the hands of developers, okay, we will not get hit. We will just put

  • it out there. No, that's not the way, how it works.

  • So now you have the technologies being deployed naively, and one last thing, a lot of people

  • use NoSQL databases so we can get away from the whole idea of a database administration.

  • Well, the DBA, death of a DBA had been greatly, greatly exaggerated because now, you have ‑‑

  • they have even more ‑‑ there's even more opportunities out there. You just have to

  • read the documentation and, you know, for what this database system would support. Okay?

  • So those are my points. And that's all that I have. Let's see if this thing actually just

  • run. Nope. Still running. Still running. Still running. I don't know what happened to it.

  • But what it will do, this thing will just exhaust 100% of the disk space on the server

  • that I have. So that's all I've got. Okay? Thank you guys, so much. Thanks a lot.

  • (Applause)

>> MING CHOW: Good afternoon, everyone. My name is Ming Chow and I will be speaking today

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B1 中級 美國腔

DEF CON 21 - Ming Chow - 濫用NoSQL數據庫。 (DEF CON 21 - Ming Chow - Abusing NoSQL Databases)

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    陳暐翰 發佈於 2021 年 01 月 14 日
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