Now you can trust the browser - Ben Gidley, Tim Charman - Codemotion Amsterdam 2017
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Developers are taught to 'never trust the browser' to execute their client-side JavaScript. The inability for a developer to trust a browser has far reaching implications from not trusting client-side validation, to never being really sure the TLS connection doesn't have a man-in-the-middle. Software security such as white-box cryptography & obfuscation have been used in native environments for many years, but these techniques are hard in JS. We'll explain how these techniques can now be applied to JS code running in a web browser to secure it from MITM attacks.
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Now you can trust the browser - Ben Gidley, Tim Charman - Codemotion Amsterdam 2017
- 1. ©2017 Irdeto, All Rights Reserved. – www.irdeto.com 1 Now you can trust the browser Ben Gidley, Tim Charman AMSTERDAM 16 - 17 MAY 2017
- 2. ©2017 Irdeto, All Rights Reserved. – www.irdeto.com 2 State of the Web TLS and Certificates Sandbox HTML JavaScript CSS Network Security IDS WAF RASP
- 3. ©2017 Irdeto, All Rights Reserved. – www.irdeto.com 3 1 - Browsers are controlled by users VS.
- 4. ©2017 Irdeto, All Rights Reserved. – www.irdeto.com 4 2 -TLS is all about protecting the consumer What does this mean exactly? • The connection is encrypted, and only people the consumers computer trusts can intercept it • A certificate authority has verified the owner of the domain has approved the certificate And that’s all it promises
- 5. ©2017 Irdeto, All Rights Reserved. – www.irdeto.com 5 2 - TLS is all about protecting the consumer What does this mean exactly? As the web site operator you have no idea if • The connection has been intercepted • The user is a person or a bot • Your client side code is running
- 6. ©2017 Irdeto, All Rights Reserved. – www.irdeto.com 6 User is innocent, yet ▪ Zero day in browser ▪ Zero day in TLS/SSL on server ▪ Incorrectly trusted certificate ▪ Vendor issued but leaked trust certificate ▪ Hijack update mechanism for any software on the device ▪ Trojan software that exploits device User unknowingly does something to make it easy ▪ Convince user to install MITM certificate ▪ Convince user to plug in USB drive ▪ Convince user to install software ▪ Malicious browser extensions 3 - TLS MITM is actually quite easy – 10 ways to do it… For more details see bit.ly/mitm-is-easy
- 7. ©2017 Irdeto, All Rights Reserved. – www.irdeto.com 7 ©2017 Irdeto, All Rights Reserved. – www.irdeto.com Demo
- 8. ©2017 Irdeto, All Rights Reserved. – www.irdeto.com 8 So what have we learnt ▪ You can’t really trust the browser ▪ Anything running in the browser may or may not run ▪ Any data sent may be modified by the user or third parties So should we all go back to pen & paper? ▪ No! What IF we could ▪ Load a trusted set of code into the browser ▪ Validate the code at load and runtime ▪ Encrypt / decrypt in the browser and not have the keys stolen
- 9. ©2017 Irdeto, All Rights Reserved. – www.irdeto.com 9 The Problem Browser Web App Web Site Web Site Unprotected HTML/JS/CSS Can we check what’s running on the client?
- 10. ©2017 Irdeto, All Rights Reserved. – www.irdeto.com 10 1st Attempt Browser Unprotected Web App Security Libraries Verification Verification Web Site Web Site Unprotected HTML/JS/CSS Web Site To be protected JavaScript
- 11. ©2017 Irdeto, All Rights Reserved. – www.irdeto.com 11 Browser 2nd Attempt Unprotected Web App Protected Web App Security Libraries Verification Verification Web Site Web Site Unprotected HTML/JS/CSS Web Site To be protected JavaScript Obfuscation
- 12. ©2017 Irdeto, All Rights Reserved. – www.irdeto.com 12 3rd Attempt Browser Unprotected Web App Protected Web App Security Libraries Verification Obfuscation Verification Web Site Web Site Unprotected HTML/JS/CSS Web Site To be protected JavaScript Whitebox Crypto But is that enough?
- 13. ©2017 Irdeto, All Rights Reserved. – www.irdeto.com 13 The solution! Verification Diversification Verification Logging Web Site Web Site Unprotected HTML/JS/CSS Web Site To be protected JavaScript Browser Unprotected Web App Protected Web App Security Libraries Whitebox Crypto
- 14. ©2017 Irdeto, All Rights Reserved. – www.irdeto.com 14 So what have we achieved? Verification Diversification Verification Logging Web Site Web Site Unprotected HTML/JS/CSS Web Site To be protected JavaScript Secured connection with private whitebox keys Tamper detection Browser Unprotected Web App Protected Web App Security Libraries Whitebox Crypto
- 15. ©2017 Irdeto, All Rights Reserved. – www.irdeto.com 15 So is this really possible? This may sound a bit like black magic, We’re claiming by mixing ▪ Obfuscation ▪ Diversity ▪ Whiteboxes I can change the security model of the browser to let us have some degree of trust, in the process stopping Man-In-The-Middle attacks and hindering a bunch of other common attacks
- 16. ©2017 Irdeto, All Rights Reserved. – www.irdeto.com 16 Whitebox AES was invented in 2004 by Cloakware (part of Irdeto) and is based on a mathematical approach We write a special AES implementation and then ‘bake’ a key into it to make it possible to use it without exposing the key. See bit.ly/whitebox-tutorial for the (basic version) of the maths Whitebox Cryptography Key Seed Transcoder Whitebox Code Whitebox Instance
- 17. ©2017 Irdeto, All Rights Reserved. – www.irdeto.com 17 Tethered Integrity Verification Easiest way to explain this is to show it…. Assuming I don’t trust Tim here…
- 18. ©2017 Irdeto, All Rights Reserved. – www.irdeto.com 18 Obfuscated JavaScript Security Library Seeds
- 19. ©2017 Irdeto, All Rights Reserved. – www.irdeto.com 19 Making security inseparable from your software Multi-Layered and Interlocked Protection Debug Detection & Anti-Debug Node-locking Secured Storage Code Encryption Obfuscated Code Diversity & Renewability Data Flow Transformation White Box Cryptography and Key Hiding Control Flow Transformation Integrity Verification ● Protect code against a collection of attacks ● Provides a multi-layered and interlocked defences ● Making the security layer inseparable from the code being protected
- 20. ©2017 Irdeto, All Rights Reserved. – www.irdeto.com 20 ©2017 Irdeto, All Rights Reserved. – www.irdeto.com So let’s see it all working
- 21. ©2017 Irdeto, All Rights Reserved. – www.irdeto.com 21 Option 1) ▪ You could implement this yourselves ▪ (But it’s quite tricky to do it right) Option 2) ▪ Use Irdeto’s SaaS How to use this type of solution in the real world
- 22. ©2017 Irdeto, All Rights Reserved. – www.irdeto.com 22 ©2017 Irdeto, All Rights Reserved. – www.irdeto.com If you have more questions please come see us in the sponsors area. Questions?
Editor's Notes
- While displayed do intro I’m Ben Gidley, Director of Technology for Irdeto a company based in Hoofddorp, just by the airport, who specialize in Digital Platform Security. I’m a developer by background and have worked in media and cyber security for a number of years. My name is Tim Charman, an Architect at Irdeto, my background is systems integration and managing data across government, media, manufacturing and payments. Ben: Today we’re going to talk about browser security and some of the new options emerging to secure code running in it. This is especially important given the recent trend for serverless apps and more and more ‘smarts’ being run in the browser.
- TIM The web is a great thing, and it’s quite successful. The basic architecture has a number of security elements built in Firewalls and network security for the servers Browser sandboxing, isolation for the browser TLS/SSL for the network Ben BUT even with all this we ‘don’t trust the browser’ to run our JavaScript code. There are a three core reasons
- Tim Browsers are controlled by users. Users pick them, install them and can make the do whatever you want. The developer writing a website can only be sure 2 things have happened Someone has downloaded your HTML/JS/CSS You got some data back What happens out on the browser will vary – it could be the user loads your page, runs your JavaScript, and does what you tested. It could also be they did something entirely different, or that they are not a human at all and instead are a bot feeding data to your server. Some users want to play by the rules, others don’t. Those that don’t can change your code and ‘mess’ with it.
- Ben TLS as deployed to consumers asserts 2 things The connection is encrypted, and only people the consumers computer trusts can intercept it A certificate authority has verified the owner of the domain has approved the certificate There is little certainty for the consumer about what code was downloaded Most consumers don’t understand this, they just know “things are secure now”.
- Ben It tells you, the server API, NOTHING about the consumer and the integrity of the connection. The only exception to this is 2 way TLS, but that’s too hard for most consumers. 2 Way TLS is where the consumer has a personal certificate, they securely store on their computer which identifies them. The problem is most people can’t keep their computers secure, and most likely don’t even know it exists.
- Tim Introduce 3 MITM For more details see http://bit.ly/mitm-is-easy Ben CITE Google/Firefox research that 10-18% of all connections are MITM’d in real world! Some of this is ‘harmless’ corporate proxies Some of this is incompetence from AV vendors/IT departments Some of this is hackers But don’t just believe us let’s see how easy it is…
- Pineapple Kali – hotspot Chromebook – join evil hotspot Install Certificate I’m using site that set up right and is up to date etc Give me key and install certificate Cite IBM USB drive screw up Evil Portal This looks like a great free wifi Ask audience for who will buy it Do it twice ??? View hack see my credit card
- Tim top bit should include ‘even though reputable e-commerce site’ Ben second bit
- Tim – state problem
- We could put a server in the middle to verify checksums from the code running on the browser. However this would still leave us open to attacks – an a bad guy can simply modify the security libraries and make them tell us everything is fine and when it isn’t. Remember we can’t trust anything that’s going on in the browser.
- So what if we also obfuscated the JavaScript. This would make it difficult for an attacker to modify the code. However with just obfuscation the attacker could still ‘spoof’ our messages, they’d just have to watch what was being sent to the server and send their own messages. Can we add cryptography to sign the message?
- Now if we add Whitebox Crypto into the security library we can start signing and encrypting things. BUT what’s to stop the attacker looking at this code and extracting the keys? Well that’s the ‘magic’ of whitebox. White-box is a version of a crypto algorithm designed with the assumption that The hacker can read the memory The hacker can read the code BUT they can’t extract the key. This is very proven tech – Irdeto’s version of this is deployed on over 5 billion devices worldwide and is well suited to running in JavaScript in a browser. We’ll come back to this in a bit to explain a bit more how it’s possible. But is that enough?
- Not really If we just use a single crypto key – it’s likely to get broken. Whitebox is good, but it’s not perfect. We can however diversify. This means we change the keys, the obfuscation over time to make it even harder to hack.
- I started off by focusing on MITM attacks but this also hinders a range of other attacks. Take for example any kind of XSS attack, any attempt to modify the page will fail IV, which in turn would stop the modified code talking to the underlying API. The XSS vulnerability would still be in the page, but it would be a lot harder to exploit.
- Ben
- If if these cards…. I’ve put them in an order I know Then I give them to Tim, and ask him to Take 2 cards and put them on the bottom Go 3 cards cards from top and put next 2 card on bottom (card 4 and 5) Tell me what card you have at card 4 from top This is a simple example, but we can more complex for example if I told tim to take every other card move it up 3 etc If we build this to the business logic of the page, then Tim is forced to follow the logic to keep being able the challenges Take one off the top and put it on the top This alone isn’t enough – but when we combine with with obfuscation and diversity we can make it really difficult for Tim to know the right answers to the questions (as we obfuscate the question) and mix up the data so it’s very hard to tell us the right answer. We also add in anti-replay features to stop him just ’parroting’ a working client. This means the same operations will always give different answers. The end result is we can ask questions only someone running our code can answer. This is then fed to the whitebox algo to securely communicate the result.
- Picture Notes: Need ‘sausage machine diagram’ – ideally like this but with Keys & seeds separate and Obfuscated JS coming out on right Tim tells He has a sick cat, 🐈, and the vet has prescribed some pills. The trouble is, the cat doesn’t have the same idea about the pills as my neighbours. So for the first two days, the cat would take the pill. But the next day, no luck. So my neighbour wrapped the pill in pate. The cat likes pate, but that only worked for two more days. So my neighbour ground up the pill and mixed it with a bit of cat food. Again, after two days it had learnt. The last thing he tried is lifting the cats top lip up, which makes it drop its bottom jaw, shoves in the pill, and makes it swallow. After two days, the cat learnt to regurgitate the pill. Now he’s stuck. With the right tooling you can generate as many techniques/JavaScript as you need. This makes it robust against attack as a hacker who figures out your technique has broken only instance, which most cases means they figured out how to hack they are currently using – e.g. they stolen their own credit card.
- 19
- Demo of it working and showing encrypted code. Show tamper detection failing
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