Dev and Blind - Attacking the weakest Link in IT Security
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The talk by Johannes Hofmann and Mario Heiderich addresses the vulnerabilities and security challenges faced by developers in IT security, highlighting the misguided perceptions that lead to insecure coding practices. They outline offensive techniques that attackers could use against developers and emphasize the necessity of stronger security measures and awareness among developers. The presentation concludes with actionable advice for enhancing security, such as adopting a least privilege policy and employing best practices in software management.
![Yes we can!
Let's see how!
Attacker sends the victim a presentation -
Preferrably in OpenOffice format
The first page is overlayed with a huge link
The link points to a local DOMXSS - for example this one
file:///usr/share/couchdb/www/couch_tests.html#?data:,alert(location)//
var testsPath = document.location.toString().split('?')[1];
Why OpenOffice? Because it jumps to file:/// URIs without asking
Now what?](https://image.slidesharecdn.com/devandblind-101129093223-phpapp02/85/Dev-and-Blind-Attacking-the-weakest-Link-in-IT-Security-25-320.jpg)
Dev and Blind - Attacking the weakest Link in IT Security
- 1. Dev and BlindDev and Blind Attacking the weakest link in IT security A Talk by Johannes Hofmann and Mario Heiderich Confidence 201002, Prague
- 2. Introduction Johannes Hofmann Ten years of web development experience Security advocate Senior Developer at a major european social network @c_ion Mario Heiderich PHPIDS HTML5 Security Cheat Sheet Researcher for RUB and Microsoft Web Developer Background @0x6d6172696f
- 3. What's to come Why to attack developers A lot of love What's the „web dev dilemma“ Attacks against developers Be prepared to see scary things New offensive techniques – so fresh they don't even have an acronym yet Protection mechanisms that really work Discussion and Q&A
- 4. Developers vs. Security folks It's not really love connecting us... Developers create crappy code Especially web developers do! It happens all the time, every day Devs don't have any clue about anything „Just get it to work and you'll be fine!“ Security folks hate devs - despite bugs being their bread and butter Mocking developers couldn't be more fun! Remember that Debian thing in 2008?
- 5. Love is in the Air Devs create tools for people to use, attackers just abuse the work of others Good developers get fired when you sec guys release 0days Many Sec Consultants show up for a few days, slap exploit lists in your face and disappear only to repeat the process next year Security people meet in shady places and don't share their ivory tower knowledge
- 6. The Developer's LamentThe Developer's Lament
- 7. The Developer's Lament 1/2 Security hurts performance Security hurts user acceptance Security hurts development time Even relative security is expensive Faulty security only becomes notable once it's too late
- 8. The Developer's Lament 2/2 Execs believe that security can be bought (stern look at audience) Maybe a fancy IBM scanner license for 33K USD? Dependencies on third-party code and services make it hard to audit a system in it's entirety Can you audit a large 200+ table monster at all? Unreviewed legacy code is everywhere - but refactoring is not a priority The deadline reigns supreme And worst of all we're juicy attack targets ourselves...
- 9. Why is that? Developer machines are located in the "secure" Intranet Devs are usually allowed to have highest privileges on their workstations Developers are using web based tools and store tons of credentials in their browsers Developers are power users and use a wide variety of software Developers are well connected and easy to reach Twitter, Facebook, Skype, GTalk, ICQ... They usually have unrestricted access to the extranet during work hours
- 10. What to attack? Development Tools Communication Tools Code Repositories Knowledge Bases and Documentation Software Browser Extensions for Developers Administrative Backends Project Management Software Server Management Interfaces Cloud Service Management Consoles
- 11. Attacking Firebug 1/2 Firebug is a Firefox extension assisting developers with their frontend work Debugging, DOM Inspection, JavaScript Console, Network Monitor and more Downloaded about 30 Million times Developers tend to have it activated at all time - for own and foreign websites Security people love the tool too - eases client side pentesting
- 12. Attacking Firebug 2/2 Unfortunately we can execute code on the machines of developers using Firebug Not too difficult to exploit actually
- 13. Attacking IDE Code execution in a Firefox extension is bad - and has major impact But what's even worse is messing with the developer's most important tool The Integreated Development Environment Such as Eclipse or the Zend Studio
- 14. From China with Love What about code execution in Zend Studio Discovered by the infamous 80vul team from China JavaScript in a Docblock - leading to full stack code execution via ActiveX
- 15. Admin Backends There's a cloud of tools available out there to help devs with their daily tasks phpMyAdmin Plesk Confixx OTRS The usually run in intranet context - not accessible from the outside An outbound attacker cannot navigate them - so why bother about security too much The intranet is for internal people only anyway - so why give a damn?
- 16. So things like these... Plesk XSS Or some OTRS XSS … shouldn't be that much of a problem
- 17. Or is it?Or is it?Ur mother hax box at Dell!Ur mother hax box at Dell!
- 18. Intranet XSS? Meh. Big problem it is. The attacker can Enumerate resources Manipulate data Sniff internal passwords and other things All pretty scary but none of this is new... What would be the holy grail for a bad guy attacking developers and their companies? IXSSSVN attacks – Go Team Acronym!
- 19. Time for the juicy stuff! Remember us mentioning Eclipse some slides ago? There's a nice bug related to nullbytes - anything behind one disappears but still exists in the edited file Awesome for code smuggling – in case you have commit privileges Usually the attacker doesn't...
- 20. Scenario! Well imagine you can execute JavaScript with an Intranet XSS For example on a Trac or similar It's not hard to find out about the SVN URL now Even easier if the repositiory is public - like svn.twitter.com :D Now imagine the setup: XSS on https://intranet.compwny.com/trac/ SVN is on https://intranet.compwny.com/svn/ Not so untypical. Realize something? SOP says yay!
- 21. XSS the SVN - so what! SVN is usually interfaced with mod_dav_svn WebDAV - no more than HTTP with extra bacon JavaScript can generate HTTP requests Oh... Wait .. But do we have to re-implement the whole DAV protocol dance in JavaScript? No - there's a lib for and it's free! DavClient
- 22. Intranet XSS gone wild So with an Intranet XSS we can do SVN commits And we can smuggle code into the Compwny's repository But everyone will notice! No! We use the nullbyte trick to hide the code They will notice at some point but it's really gonna take time if the attacker is lucky And do you remember the attack against Zend Studio? Scared already?
- 23. More ways to bust you Imagine an attacker aching for your local files Imagine you are head of development and keep the company password list on your machine Yes - stuff like that exists But how to get hands on that precious file?
- 24. DOMXSS will do the trick What the.. what? DOMXSS? That lousy useless technique no one cares about? Yep - that one Think local this time There a huge bunch of webapps on your harddrive - even with a freshly installed OS Documentations, help systems, CouchDB etc. etc. Buggy as hell! Even Ubuntu 10 ships tons of Local DOMXSS right after installing! So we can theoretically use JavaScript to access YOUR harddrive?
- 25. Yes we can! Let's see how! Attacker sends the victim a presentation - Preferrably in OpenOffice format The first page is overlayed with a huge link The link points to a local DOMXSS - for example this one file:///usr/share/couchdb/www/couch_tests.html#?data:,alert(location)// var testsPath = document.location.toString().split('?')[1]; Why OpenOffice? Because it jumps to file:/// URIs without asking Now what?
- 26. Now for stealing some files We cannot do a lot here using only the browser XHR to local files is limited to the directory the XSS happens in - no way to traverse down to / or C:/// Kind of a SOP extension to secure users But luckily we have a helper *burp* … Java!
- 27. Step by Step Just create a malicious applet Load it with the DOMXSS from any resource and crawl The chain of OpenOffice, local DOMXSS and a Java Applet leads to stealing local files And local DOMXSS is legion - check the Eclipse help files
- 28. So we're doomed, aren't we?So we're doomed, aren't we?
- 29. The big questions Do what now? What can be done to protect your asse(t)s? Is there a way out of the developer dilemma?
- 30. Protect yourself Don't **** where you eat Never reuse private passwords Chain your Mail Accounts – mitigate pwnage Do not publish Internals via Skype, Mail or even the Calendar
- 31. NoScript et. al. Use Firefox and NoScript There's effectively no alternative on any other browser setup NoScript blocks JavaScript on file:/// URIs by default Java is being kenneled too Best disable the Java plugin itself! Least privilege policy for any website
- 32. Virtualization to the rescue! Create VMs for external or internal uses Isolate tools that work on external data Email Messaging Browsers Block external VMs from accessing the intranet Even better: separate machines
- 33. Protect your Code Vulns occur when dealing with unconsidered user input You can't remember everything, unit tests can Build a vector database and use it to fuzz your application yourself A well abstracted Framework helps a lot here Beware this ain't a catch-all
- 34. Know your stuff Handle 3rd Party software with extreme care Bad legacy code: refactor where you can Don't blindly trust the cloud - it's not your buddy Keep up Update your software Follow the security buzz Visit events like this!
- 35. Be proactive about app security! CSOs can fight the good fight at management level Security is a team efford! Attack your own app! Make internal company hack challenges Make security fun and sexy – as it is! Make creative use of rewards and punishments
- 36. How about a stupid hat for a day?
- 37. That was it Thanks for your precious time!
- 38. Appendix Debian and OpenSSL http://www.links.org/?p=327 Eclipse http://eclipse.org/ Zend Studio http://www.zend.com/de/products/studio/ The Zend Studio RCE http://80vul.com/Zend%20studio/Zend%20studio%20location%20Cross.htm Firebug https://addons.mozilla.org/de/firefox/addon/1843/ Selenium https://addons.mozilla.org/en-US/firefox/addon/2079/ DavClient http://debris.demon.nl/projects/davclient.js/doc/README.html CouchDB http://couchdb.apache.org/ Github http://github.com/ Amit Klein on DOMXSS http://www.webappsec.org/projects/articles/071105.shtml Chromium Blog on Local Web Pages http://blog.chromium.org/2008/12/security-in-depth-local-web-pages.html VirtualBox http://www.virtualbox.org/ NoScript https://addons.mozilla.org/de/firefox/addon/1843/ The guy who hosts that images we used http://www.plognark.com/ Image credits Blind guy: SkyShaper@flickr Code Monkey: plognark.com Crying guy: [email protected] A silent cry: near proximity@flickr Spy vs. Spy.; DC Comics Exorcist still: Warner Bros.
- 39. Goodies anyone? "After all that... luckily our company uses GitHub! No one can commit into our repository from the outside" Wrong again .-)